Patent Publication Number: US-2010115395-A1

Title: Data processing apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to document processing techniques, and particularly to techniques for processing structured document files described in a markup language. 
     BACKGROUND ART 
     The XML format attracts attention as a format that allows the user to share data with other users via a network. This promotes development of applications for creating, displaying, and editing XML documents (see Patent document 1, for example). The XML documents are created based upon a vocabulary (tag set) defined according to a document type definition. 
     [Patent Document 1] Japanese Patent Application Laid-open No. 2001-290804 
     DISCLOSURE OF INVENTION 
     Problems to be Solved by the Invention 
     The XML technique allows the user to define vocabularies as desired. In theory, this allows a limitless number of vocabularies to be created. It is not practical to provide dedicated display/editing environments in order to handle all such vocabularies. Conventionally, when the document described in the vocabulary, for which the special editing environment is not prepared, is to be edited, the source of the document composed of the text data was edited directly using, for example, a text editor. 
     In this background, a general purpose of the present invention is to provide a technique that improves the ease-of-use for the user in processing the data structured in a markup language. 
     Means for Solving the Problems 
     An aspect of the present invention relates to a data processing apparatus. This apparatus acquires the schema information that shows the element structure of the structured document file described in a predetermined tag set and creates the definition data in order to display the user interface screen for editing the structured document file based on the schema information. 
     Optional combinations of the aforementioned constituting elements, and implementations of the invention in the form of methods, apparatuses, and systems may also be practiced as additional modes of the present invention. 
     ADVANTAGES 
     The present invention improves the ease-of-use for the user in processing the data structured in a markup language can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which: 
         FIG. 1  is a diagram which shows a configuration of a document processing apparatus according to the Base Technology; 
         FIG. 2  is a diagram which shows an example of an XML document which is a processing target; 
         FIG. 3  is a diagram which shows an example in which the XML document shown in  FIG. 2  is mapped to a table described in HTML; 
         FIG. 4(   a ) is a diagram which shows an example of a definition file used for mapping the XML document shown in  FIG. 2  to the table shown in  FIG. 3 ; 
         FIG. 4(   b ) is a diagram which shows an example of a definition file used for mapping the XML document shown in  FIG. 2  to the table shown in  FIG. 3 ; 
         FIG. 5  is a diagram which shows an example of a screen on which the XML document, which has been described in a marks managing vocabulary and which is shown in  FIG. 2 , is displayed after having been mapped to HTML according to the correspondence shown in  FIG. 3 ; 
         FIG. 6  is a diagram which shows an example of a graphical user interface provided by a definition file creating unit, which allows the user to create a definition file; 
         FIG. 7  is a diagram which shows another example of a screen layout created by the definition file creating unit; 
         FIG. 8  is a diagram which shows an example of an editing screen for an XML document, as provided by the document processing apparatus; 
         FIG. 9  is a diagram which shows another example of an XML document which is to be edited by the document processing apparatus; 
         FIG. 10  is a diagram which shows an example of a screen on which the document shown in  FIG. 9  is displayed; 
         FIG. 11(   a ) is a diagram which shows a basic configuration of a document processing system; 
         FIG. 11(   b ) is a block diagram which shows an overall block configuration of a document processing system; 
         FIG. 11(   c ) is a block diagram which shows an overall block configuration of a document processing system; 
         FIG. 12  is a diagram which shows a document management unit in detail; 
         FIG. 13  is a diagram which shows a vocabulary connection sub-system in detail; 
         FIG. 14  is a diagram which shows a relation between a program invoker and other components in detail; 
         FIG. 15  is a diagram which shows a structure of an application service loaded to the program invoker in detail; 
         FIG. 16  is a diagram which shows a core component in detail; 
         FIG. 17  is a diagram which shows a document management unit in detail; 
         FIG. 18  is a diagram which shows an undo framework and an undo command in detail; 
         FIG. 19  is a diagram which shows the operation in which a document is loaded to the document processing system; 
         FIG. 20  is a diagram which shows an example of a document and a representation of the document; 
         FIG. 21  is a diagram which shows a relation between a model and a controller; 
         FIG. 22  is a diagram which shows a plug-in sub-system, a vocabulary connection, and a connector, in detail; 
         FIG. 23  is a diagram which shows an example of a VCD file; 
         FIG. 24  is a diagram which shows a procedure for loading a compound document to the document processing system; 
         FIG. 25  is a diagram which shows a procedure for loading a compound document to the document processing system; 
         FIG. 26  is a diagram which shows a procedure for loading a compound document to the document processing system; 
         FIG. 27  is a diagram which shows a procedure for loading a compound document to the document processing system; 
         FIG. 28  is a diagram which shows a procedure for loading a compound document to the document processing system; 
         FIG. 29  is a diagram which shows a command flow; 
         FIG. 30  is a schematic diagram which illustrates a process of creating a definition file according to the exemplary embodiment; 
         FIG. 31  is a diagram which shows a schema file according to the exemplary embodiment; 
         FIG. 32  is a diagram which shows a source file which corresponds to the schema file in  FIG. 31 ; 
         FIG. 33  is a diagram which shows a definition file created based on the schema file in  FIG. 31  and the source file in  FIG. 32 ; 
         FIG. 34  is a diagram which shows an editing screen for a binding file; 
         FIG. 35  is a diagram which shows an editing screen for a layout file based on the editing result of the binding file in  FIG. 34 ; 
         FIG. 36  is a screen view when a destination file based on the editing result in  FIG. 35  is displayed; 
         FIG. 37  is a diagram which shows another example of an editing screen for a binding file; 
         FIG. 38  is a diagram which shows an editing screen for a layout file based on the editing result of the binding file in  FIG. 37 ; 
         FIG. 39  is a screen view when a destination file based on the editing result in  FIG. 38  is displayed; 
         FIG. 40  is a diagram which further shows another example of an editing screen for a binding file; 
         FIG. 41  is a diagram which shows an editing screen for a layout file based on the editing result of the binding file in  FIG. 40 ; 
         FIG. 42  is a screen view when a destination file based on the editing result in  FIG. 41  is displayed; 
         FIG. 43  is a diagram which further shows another example of an editing screen for a binding file; 
         FIG. 44  is a diagram which shows an editing screen for a layout file based on the editing result of the binding file in  FIG. 43 ; 
         FIG. 45  is a screen view when a destination file based on the editing result in  FIG. 44  is displayed; and 
         FIG. 46  is a schematic diagram which further illustrates a process of creating a definition file. 
     
    
    
     REFERENCE NUMERALS 
       20  document processing apparatus,  22  main control unit,  24  editing unit,  30  DOM unit,  32  DOM provider,  34  DOM builder,  36  DOM writer,  40  CSS unit,  42  CSS parser,  44  CSS provider,  46  rendering unit,  50  HTML unit,  52 ,  62  control unit,  54 ,  64  editing unit,  56 ,  66  display unit,  60  SVG unit,  80  VC unit,  82  mapping unit,  84  definition file acquisition unit,  86  definition file creating unit 
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Base Technology 
       FIG. 1  illustrates a structure of a document processing apparatus  20  according to Base Technology. The document processing apparatus  20  processes a structured document where data in the document are classified into a plurality of components having a hierarchical structure. Represented in Base Technology is an example in which an XML document, as one type of a structured document, is processed. The document processing apparatus  20  is comprised of a main control unit  22 , an editing unit  24 , a DOM unit  30 , a CSS unit  40 , an HTML unit  50 , an SVG unit  60  and a VC unit  80  which serves as an example of a conversion unit. In terms of hardware components, these unit structures may be realized by any conventional processing system or equipment, including a CPU or memory of any computer, a memory-loaded program, or the like. Here, the drawing shows a functional block configuration which is realized by cooperation between the hardware components and software components. Thus, a person skilled in the art should appreciate that there are many ways of accomplishing these functional blocks in various forms in accordance with the components of hardware only, software only, or the combination of both. 
     The main control unit  22  provides for the loading of a plug-in or a framework for executing a command. The editing unit  24  provides a framework for editing XML documents. Display and editing functions for a document in the document processing apparatus  20  are realized by plug-ins, and the necessary plug-ins are loaded by the main control unit  22  or the editing unit  24  according to the type of document under consideration. The main control unit  22  or the editing unit  24  determines which vocabulary or vocabularies describes the content of an XML document to be processed, by referring to a name space of the document to be processed, and loads a plug-in for display or editing corresponding to the thus determined vocabulary so as to execute the display or the editing. For instance, an HTML unit  50 , which displays and edits HTML documents, and an SVG unit  60 , which displays and edits SVG documents, are implemented in the document processing apparatus  20 . That is, a display system and an editing system are implemented as plug-ins for each vocabulary (tag set), so that when an HTML document and an SVG document are edited, HTML unit  50  and the SVG unit  60  are loaded, respectively. As will be described later, when compound documents, which contain both HTML and SVG components, are to be processed, both HTML unit  50  and the SVG unit  60  are loaded. 
     By implementing the above structure, a user can select so as to install only necessary functions, and can add or delete a function or functions at a later stage, as appropriately. Thus, the storage area of a recording medium, such as a hard disk, can be effectively utilized, and the wasteful use of memory can be prevented at the time of executing programs. Furthermore, since the capability of this structure is highly expandable, a developer can deal with new vocabularies in the form of plug-ins, and thus the development process can be readily facilitated. As a result, the user can also add a function or functions easily at low cost by adding a plug-in or plug-ins. 
     The editing unit  24  receives an event, which is an editing instruction, from the user via the user interface. Upon reception of such an event, the editing unit  24  notifies a suitable plug-in or the like of this event, and controls the processing such as redoing this event, canceling (undoing) this event, etc. 
     The DOM unit  30  includes a DOM provider  32 , a DOM builder  34  and a DOM writer  36 . The DOM unit  30  realizes functions in compliance with a document object model (DOM), which is defined to provide an access method used for handling data in the form of an XML document. The DOM provider  32  is an implementation of a DOM that satisfies an interface defined by the editing unit  24 . The DOM builder  34  creates DOM trees from XML documents. As will be described later, when an XML document to be processed is mapped to another vocabulary by the VC unit  80 , a source tree, which corresponds to the XML document in a mapping source, and a destination tree, which corresponds to the XML document in a mapping destination, are created. At the end of editing, for example, the DOM writer  36  outputs a DOM tree as an XML document. 
     The CSS unit  40 , which provides a display function conforming to CSS, includes a CSS parser  42 , a CSS provider  44  and a rendering unit  46 . The CSS parser  42  has a parsing function for analyzing the CSS syntax. The CSS provider  44  is an implementation of a CSS object and performs CSS cascade processing on the DOM tree. The rendering unit  46  is a CSS rendering engine and is used to display documents, described in a vocabulary such as HTML, which are laid out using CSS. 
     HTML unit  50  displays or edits documents described in HTML. The SVG unit  60  displays or edits documents described in SVG. The SVG unit  60  displays or edits documents described in SVG. These display/editing systems are realized in the form of plug-ins, and each system is comprised of a display unit (also designated herein as a “canvas”)  56  and  66 , which displays documents, a control unit (also designated herein as an “editlet”)  52  and  62 , which transmits and receives events containing editing commands, and an edit unit (also designated herein as a “zone”)  54  and  64 , which edits the DOM according to the editing commands. Upon the control unit  52  or  62  receiving a DOM tree editing command from an external source, the edit unit  54  or  64  modifies the DOM tree and the display unit  56  or  66  updates the display. These units have a structure similar to the framework of the so-called MVC (Model-View-Controller). With such a structure, in general, the display units  56  and  66  correspond to “View”. On the other hand, the control units  52  and  62  correspond to “Controller”, and the edit units  54  and  64  and DOM instance corresponds to “Model”. HTML unit  50  provides a user interface for editing an HTML document in a manner similar to a word processor, for example. On the other hand, the SVG unit  60  provides a user interface for editing an SVG document in a manner similar to an image drawing tool. 
     The VC unit  80  includes a mapping unit  82 , a definition file acquiring unit  84  and a definition file generator  86 . The VC unit  80  performs mapping of a document, which has been described in a particular vocabulary, to another given vocabulary, thereby providing a framework that allows a document to be displayed and edited by a display/editing plug-in corresponding to the vocabulary to which the document is mapped. In the Base Technology, this function is called a vocabulary connection (VC). In the VC unit  80 , the definition file acquiring unit  84  acquires a script file in which the mapping definition is described. 
     Here, the definition file specifies the correspondence (connection) between the Nodes for each Node. Furthermore, the definition file may specify whether or not editing of the element values or attribute values is permitted. Furthermore, the definition file may include operation expressions using the element values or attribute values for the Node. Detailed description will be made later regarding these functions. The mapping unit  82  instructs the DOM builder  34  to create a destination tree with reference to the script file acquired by the definition file acquiring unit  84 . This manages the correspondence between the source tree and the destination tree. The definition file generator  86  offers a graphical user interface which allows the user to create a definition file. 
     The VC unit  80  monitors the connection between the source tree and the destination tree. Upon reception of an editing instruction from the user via a user interface provided by a plug-in that handles a display function, the VC unit  80  first modifies a relevant Node of the source tree. As a result, the DOM unit  30  issues a mutation event indicating that the source tree has been modified. Upon reception of the mutation event thus issued, the VC unit  80  modifies a Node of the destination tree corresponding to the modified Node, thereby updating the destination tree in a manner that synchronizes with the modification of the source tree. Upon reception of a mutation event that indicates that the destination tree has been modified, a plug-in having functions of displaying/editing the destination tree, e.g., HTML unit  50 , updates a display with reference to the destination tree thus modified. Such a structure allows a document described in any vocabulary, even a minor vocabulary used in a minor user segment, to be converted into a document described in another major vocabulary. This enables such a document described in a minor vocabulary to be displayed, and provides an editing environment for such a document. 
     An operation in which the document processing apparatus  20  displays and/or edits documents will be described herein below. When the document processing apparatus  20  loads a document to be processed, the DOM builder  34  creates a DOM tree from the XML document. The main control unit  22  or the editing unit  24  determines which vocabulary describes the XML document by referring to a name space of the XML document to be processed. If the plug-in corresponding to the vocabulary is installed in the document processing apparatus  20 , the plug-in is loaded so as to display/edit the document. If, on the other hand, the plug-in is not installed in the document processing apparatus  20 , a check shall be made to see whether a mapping definition file exists or not. And if the definition file exits, the definition file acquiring unit  84  acquires the definition file and creates a destination tree according to the definition, so that the document is displayed/edited by the plug-in corresponding to the vocabulary which is to be used for mapping. If the document is a compound document containing a plurality of vocabularies, relevant portions of the document are displayed/edited by plug-ins corresponding to the respective vocabularies, as will be described later. If the definition file does not exist, a source or tree structure of a document is displayed and the editing is carried out on the display screen. 
       FIG. 2  shows an example of an XML document to be processed. According to this exemplary illustration, the XML document is used to manage data concerning grades or marks that students have earned. A component “marks”, which is the top Node of the XML document, includes a plurality of components “student” provided for each student under “marks”. The component “student” has an attribute “name” and contains, as child elements, the subjects “japanese”, “mathematics”, “science”, and “social_studies”. The attribute “name” stores the name of a student. The components “Japanese”, “mathematics”, “science” and “social_studies” store the test scores for the subjects Japanese, mathematics, science, and social studies, respectively. For example, the marks of a student whose name is “A” are “90” for Japanese, “50” for mathematics, “75” for science and “60” for social studies. Hereinafter, the vocabulary (tag set) used in this document will be called “marks managing vocabulary”. 
     Here, the document processing apparatus  20  according to the Base Technology does not have a plug-in which conforms to or handles the display/editing of marks managing vocabularies. Accordingly, before displaying such a document in a manner other than the source display manner or the tree display manner, the above-described VC function is used. That is, there is a need to prepare a definition file for mapping the document, which has been described in the marks managing vocabulary, to another vocabulary, which is supported by a corresponding plug-in, e.g., HTML or SVG. Note that description will be made later regarding a user interface that allows the user to create the user&#39;s own definition file. Now, description will be made below regarding a case in which a definition file has already been prepared. 
       FIG. 3  shows an example in which the XML document shown in  FIG. 2  is mapped to a table described in HTML. In an example shown in  FIG. 3 , a “student” Node in the marks managing vocabulary is associated with a row (“TR” Node) of a table (“TABLE” Node) in HTML. The first column in each row corresponds to an attribute value “name”, the second column to a “Japanese” Node element value, the third column to a “mathematics” Node element value, the fourth column to a “science” Node element value and the fifth column to a “social_studies” Node element value. As a result, the XML document shown in  FIG. 2  can be displayed in an HTML tabular format. Furthermore, these attribute values and element values are designated as being editable, so that the user can edit these values on a display screen using an editing function of HTML unit  50 . In the sixth column, an operation expression is designated for calculating a weighted average of the marks for Japanese, mathematics, science and social studies, and average values of the marks for each student are displayed. In this manner, more flexible display can be effected by making it possible to specify the operation expression in the definition file, thus improving the users&#39; convenience at the time of editing. In this example shown in  FIG. 3 , editing is designated as not being possible in the sixth column, so that the average value alone cannot be edited individually. Thus, in the mapping definition it is possible to specify editing or no editing so as to protect the users against the possibility of performing erroneous operations. 
       FIG. 4(   a ) and  FIG. 4(   b ) illustrate an example of a definition file to map the XML document shown in  FIG. 2  to the table shown in  FIG. 3 . This definition file is described in script language defined for use with definition files. In the definition file, definitions of commands and templates for display are described. In the example shown in  FIG. 4(   a ) and  FIG. 4(   b ), “add student” and “delete student” are defined as commands, and an operation of inserting a Node “student” into a source tree and an operation of deleting the Node “student” from the source tree, respectively, are associated with these commands. Furthermore, the definition file is described in the form of a template, which describes that a header, such as “name” and “Japanese”, is displayed in the first row of a table and the contents of the Node “student” are displayed in the second and subsequent rows. In the template displaying the contents of the Node “student”, a term containing “text-of” indicates that editing is permitted, whereas a term containing “value-of” indicates that editing is not permitted. Among the rows where the contents of the Node “student” are displayed, an operation expression “(src:japanese+src:mathematics+scr:science+scr:social_studies) div 4” is described in the sixth row. This means that the average of the student&#39;s marks is displayed. 
       FIG. 5  shows an example of a display screen on which an XML document described in the marks managing vocabulary shown in  FIG. 2  is displayed by mapping the XML document to HTML using the correspondence shown in  FIG. 3 . Displayed from left to right in each row of a table  90  are the names of each student, marks for Japanese, marks for mathematics, marks for science, marks for social studies and the averages thereof. The user can edit the XML document on this screen. For example, when the value in the second row and the third column is changed to “70”, the element value in the source tree corresponding to this Node, that is, the marks of student “B” for mathematics are changed to “70”. At this time, in order to have the destination tree follow the source tree, the VC unit  80  changes a relevant portion of the destination tree accordingly, so that HTML unit  50  updates the display based on the destination tree thus changed. Hence, the marks of student “B” for mathematics are changed to “70”, and the average is changed to “55” in the table on the screen. 
     On the screen as shown in  FIG. 5 , commands like “add student” and “delete student” are displayed in a menu as defined in the definition file shown in  FIG. 4(   a ) and  FIG. 4(   b ). When the user selects a command from among these commands, a Node “student” is added or deleted in the source tree. In this manner, with the document processing apparatus  20  according to the Base Technology, it is possible not only to edit the element values of components in a lower end of a hierarchical structure but also to edit the hierarchical structure. An edit function for editing such a tree structure may be presented to the user in the form of commands. Furthermore, a command to add or delete rows of a table may, for example, be linked to an operation of adding or deleting the Node “student”. A command to embed other vocabularies therein may be presented to the user. This table may be used as an input template, so that marks data for new students can be added in a fill-in-the-blank format. As described above, the VC function allows a document described in the marks managing vocabulary to be edited using the display/editing function of HTML unit  50 . 
       FIG. 6  shows an example of a graphical user interface, which the definition file generator  86  presents to the user, in command for the user to create a definition file. An XML document to be mapped is displayed in a tree in a left-hand area  91  of a screen. The screen layout of an XML document after mapping is displayed in a right-hand area  92  of the screen. This screen layout can be edited by HTML unit  50 , and the user creates a screen layout for displaying documents in the right-hand area  92  of the screen. For example, a Node of the XML document which is to be mapped, which is displayed in the left-hand area  91  of the screen, is dragged and dropped into HTML screen layout in the right-hand area  92  of the screen using a pointing device such as a mouse, so that a connection between a Node at a mapping source and a Node at a mapping destination is specified. For example, when “mathematics,” which is a child element of the element “student,” is dropped to the intersection of the first row and the third column in a table  90  on HTML screen, a connection is established between the “mathematics” Node and a “TD” Node in the third column. Either editing or no editing can be specified for each Node. Moreover, the operation expression can be embedded in a display screen. When the screen editing is completed, the definition file generator  86  creates definition files, which describe connections between the screen layout and Nodes. 
     Viewers or editors which can handle major vocabularies such as XHTML, MathML and SVG have already been developed. However, it does not serve any practical purpose to develop dedicated viewers or editors for such documents described in the original vocabularies as shown in  FIG. 2 . If, however, the definition files for mapping to other vocabularies are created as mentioned above, the documents described in the original vocabularies can be displayed and/or edited utilizing the VC function without the need to develop a new viewer or editor. 
       FIG. 7  shows another example of a screen layout created by the definition file generator  86 . In the example shown in  FIG. 7 , a table  90  and circular graphs  93  are created on a screen for displaying XML documents described in the marks managing vocabulary. The circular graphs  93  are described in SVG. As will be discussed later, the document processing apparatus  20  according to the Base Technology can process a compound document described in the form of a single XML document according to a plurality of vocabularies. That is why the table  90  described in HTML and the circular graphs  93  described in SVG can be displayed on the same screen. 
       FIG. 8  shows an example of a display medium, which in a preferred but non-limiting embodiment is an editing screen, for XML documents processed by the document processing apparatus  20 . In the example shown in  FIG. 8 , a single screen is partitioned into a plurality of areas and the XML document to be processed is displayed in a plurality of different display formats at the respective areas. The source of the document is displayed in an area  94 , the tree structure of the document is displayed in an area  95 , and the table shown in  FIG. 5  and described in HTML is displayed in an area  96 . The document can be edited in any of these areas, and when the user edits content in any of these areas, the source tree will be modified accordingly, and then each plug-in that handles the corresponding screen display updates the screen so as to effect the modification of the source tree. Specifically, display units of the plug-ins in charge of displaying the respective editing screens are registered in advance as listeners for mutation events that provide notice of a change in the source tree. When the source tree is modified by any of the plug-ins or the VC unit  80 , all the display units, which are displaying the editing screen, receive the issued mutation event(s) and then update the screens. At this time, if the plug-in is executing the display through the VC function, the VC unit  80  modifies the destination tree following the modification of the source tree. Thereafter, the display unit of the plug-in modifies the screen by referring to the destination tree thus modified. 
     For example, when the source display and tree-view display are implemented by dedicated plug-ins, the source-display plug-in and the tree-display plug-in execute their respective displays by directly referring to the source tree without involving the destination tree. In this case, when the editing is done in any area of the screen, the source-display plug-in and the tree-display plug-in update the screen by referring to the modified source tree. Also, HTML unit  50  in charge of displaying the area  96  updates the screen by referring to the destination tree, which has been modified following the modification of the source tree. 
     The source display and the tree-view display can also be realized by utilizing the VC function. That is to say, an arrangement may be made in which the source and the tree structure are laid out in HTML, an XML document is mapped to HTML structure thus laid out, and HTML unit  50  displays the XML document thus mapped. In such an arrangement, three destination trees in the source format, the tree format and the table format are created. If the editing is carried out in any of the three areas on the screen, the VC unit  80  modifies the source tree and, thereafter, modifies the three destination trees in the source format, the tree format and the table format. Then, HTML unit  50  updates the three areas of the screen by referring to the three destination trees. 
     In this manner, a document is displayed on a single screen in a plurality of display formats, thus improving a user&#39;s convenience. For example, the user can display and edit a document in a visually easy-to-understand format using the table  90  or the like while understanding the hierarchical structure of the document by the source display or the tree display. In the above example, a single screen is partitioned into a plurality of display formats, and they are displayed simultaneously. Also, a single display format may be displayed on a single screen so that the display format can be switched according to the user&#39;s instructions. In this case, the main control unit  22  receives from the user a request for switching the display format and then instructs the respective plug-ins to switch the display. 
       FIG. 9  illustrates another example of an XML document edited by the document processing apparatus  20 . In the XML document shown in  FIG. 9 , an XHTML document is embedded in a “foreignObject” tag of an SVG document, and the XHTML document contains an equation described in MathML. In this case, the editing unit  24  assigns the rendering job to an appropriate display system by referring to the name space. In the example illustrated in  FIG. 9 , first, the editing unit  24  instructs the SVG unit  60  to render a rectangle, and then instructs HTML unit  50  to render the XHTML document. Furthermore, the editing unit  24  instructs a MathML unit (not shown) to render an equation. In this manner, the compound document containing a plurality of vocabularies is appropriately displayed.  FIG. 10  illustrates the resulting display. 
     The displayed menu may be switched corresponding to the position of the cursor (carriage) during the editing of a document. That is, when the cursor lies in an area where an SVG document is displayed, the menu provided by the SVG unit  60 , or a command set which is defined in the definition file for mapping the SVG document, is displayed. On the other hand, when the cursor lies in an area where the XHTML document is displayed, the menu provided by HTML unit  50 , or a command set which is defined in the definition file for mapping HTML document, is displayed. Thus, an appropriate user interface can be presented according to the editing position. 
     In a case that there is neither a plug-in nor a mapping definition file suitable for any one of the vocabularies according to which the compound document has been described, a portion described in this vocabulary may be displayed in source or in tree format. In the conventional practice, when a compound document is to be opened where another document is embedded in a particular document, their contents cannot be displayed without the installation of an application to display the embedded document. According to the Base Technology, however, the XML documents, which are composed of text data, may be displayed in source or in tree format so that the contents of the documents can be ascertained. This is a characteristic of the text-based XML documents or the like. 
     Another advantageous aspect of the data being described in a text-based language, for example, is that, in a single compound document, a part of the compound document described in a given vocabulary can be used as reference data for another part of the same compound document described in a different vocabulary. Furthermore, when a search is made within the document, a string of characters embedded in a drawing, such as SVG, may also be search candidates. 
     In a document described in a particular vocabulary, tags belonging to other vocabularies may be used. Though such an XML document is generally not valid, it can be processed as a valid XML document as long as it is well-formed. In such a case, the tags thus inserted that belong to other vocabularies may be mapped using a definition file. For instance, tags such as “Important” and “Most Important” may be used so as to display a portion surrounding these tags in an emphasized manner, or may be sorted out in the command of importance. 
     When the user edits a document on an editing screen as shown in  FIG. 10 , a plug-in or a VC unit  80 , which is in charge of processing the edited portion, modifies the source tree. A listener for mutation events can be registered for each Node in the source tree. Normally, a display unit of the plug-in or the VC unit  80  conforming to a vocabulary that belongs to each Node is registered as the listener. When the source tree is modified, the DOM provider  32  traces toward a higher hierarchy from the modified Node. If there is a registered listener, the DOM provider  32  issues a mutation event to the listener. For example, referring to the document shown in  FIG. 9 , if a Node which lies lower than the &lt;html&gt; Node is modified, the mutation event is notified to HTML unit  50 , which is registered as a listener to the &lt;html&gt; Node. At the same time, the mutation event is also notified to the SVG unit  60 , which is registered as a listener in an &lt;svg&gt; Node, which lies upper to the &lt;html&gt; Node. At this time, HTML unit  50  updates the display by referring to the modified source tree. Since the Nodes belonging to the vocabulary of the SVG unit  60  itself are not modified, the SVG unit  60  may disregard the mutation event. 
     Depending on the contents of the editing, modification of the display by HTML unit  50  may change the overall layout. In such a case, the layout is updated by a screen layout management mechanism, e.g., the plug-in that handles the display of the highest Node, in increments of display regions which are displayed according to the respective plug-ins. For example, in a case of expanding a display region managed by HTML unit  50 , first, HTML unit  50  renders a part managed by HTML unit  50  itself, and determines the size of the display region. Then, the size of the display area is notified to the component that manages the screen layout so as to request the updating of the layout. Upon receipt of this notice, the component that manages the screen layout rebuilds the layout of the display area for each plug-in. Accordingly, the display of the edited portion is appropriately updated and the overall screen layout is updated. 
     Then, further detailed description will be made regarding functions and components for providing the document processing  20  according to the Base Technology. In the following description, English terms are used for the class names and so forth. 
     A. Outline 
     The advent of the Internet has resulted in a nearly exponential increase in the number of documents processed and managed by users. The Web (World Wide Web), which serves as the core of the Internet, provides a massive storage capacity for storing such document data. The Web also provides an information search system for such documents, in addition to the function of storing the documents. In general, such a document is described in a markup language. HTML (HyperText Markup Language) is an example of a popular basic markup language. Such a document includes links, each of which links the document to another document stored at another position on the Web. XML (eXtensible Markup Language) is a popular further improved markup language. Simple browsers which allow the user to access and browse such Web documents have been developed using object-oriented programming languages such as Java (trademark). 
     In general, documents described in markup languages are represented in a browser or other applications in the form of a tree data structure. This structure corresponds to a tree structure obtained as a result of parsing a document. The DOM (Document Object Model) is a well-known tree-based data structure model, which is used for representing and processing a document. The DOM provides a standard object set for representing documents, examples of which include an HTML document, an XML document, etc. The DOM includes two basic components, i.e., a standard model which shows how the objects that represent the respective components included in a document are connected to one another, and a standard interface which allows the user to access and operate each object. 
     Application developers can support the DOM as an interface for handling their own data structure and API (Application Program Interface). On the other hand, application providers who create documents can use the standard interface of the DOM, instead of using the DOM as an interface for handling their own API. The capacity of the DOM to provide such a standard interface has been effective in promoting document sharing in various environments, particularly on the Web. Several versions of the DOM have been defined, which are used in different environments and applications. 
     A DOM tree is a hierarchical representation of the structure of a document, which is based upon the content of a corresponding DOM. A DOM tree includes a “root”, and one or more “Nodes” branching from the root. In some cases, an entire document is represented by a root alone. An intermediate Node can represent an element such as a table, or a row or a column of the table, for example. A “leaf” of a DOM tree generally represents data which cannot be further parsed, such as text data, image data, etc. Each of the Nodes of the DOM tree may be associated with an attribute that specifies a parameter of the element represented by the Node, such as a font, size, color, indent, etc. 
     HTML is a language which is generally used for creating a document. However, HTML is a language that provides formatting and layout capabilities, and it is not meant to be used as a data description language. The Node of the DOM tree for representing an HTML document is defined beforehand as an HTML formatting tag, and in general, HTML does not provide detailed data description and data tagging/labeling functions. This leads to a difficulty in providing a query format for the data included in an HTML document. 
     The goal of network designers is to provide a software application which allows the user to make a query for and to process a document provided on the Web. Such a software application should allow the user to make a query for and to process a document, regardless of the display method, as long as the document is described in a hierarchically structured language. A markup language such as XML (eXtensible Markup Language) provides such functions. 
     Unlike HTML, XML has a well-known advantage of allowing the document designer to label each data element using a tag which can be defined by the document designer as desired. Such data elements can form a hierarchical structure. Furthermore, an XML document can include a document type definition that specifies a “grammar” which specifies the tags used in the document and the relations between the tags. Also, in order to define the display method of such a structured XML document, CSS (Cascading Style Sheets) or XSL (XML Style Language) is used. Additional information with respect to the features of the DOM, HTML, XML, CSS, XSL, and the related languages can be acquired via the Web, for example, from “http://www.w3.org/TR/”. 
     XPath provides common syntax and semantics which allow the position of a portion of an XML document to be specified. Examples of such functions include a function of traversing a DOM tree that corresponds to an XML document. This provides basic functions for operating character strings, values, and Boolean variables, which are related to the function of displaying an XML document in various manners. XPath does not provide a syntax for how the XML document is displayed, e.g., a grammar which handles a document in the form of text in increments of lines or characters. Instead of such a syntax, XPath handles a document in the form of an abstract and logical structure. The use of XPath allows the user to specify a position in an XML document via the hierarchical structure of a DOM tree of the XML document, for example. Also, XPath has been designed so as to allow the user to test whether or not the Nodes included in a DOM tree match a given pattern. Detailed description of XPath can be obtained from http://www.w3.org/TR/xpath. 
     There is a demand for an effective document processing system based upon the known features and advantages of XML, which provides a user-friendly interface which handles a document described in a markup language (e.g., XML), and which allows the user to create and modify such a document. 
     Some of the system components as described here will be described in a well-known GUI (Graphical User Interface) paradigm which is called the MVC (Model-View-Controller) paradigm. The MVC paradigm divides a part of an application or an interface of an application into three parts, i.e., “model”, “view”, and “controller”. In the GUI field, the MVC paradigm has been developed primarily for assigning the roles of “input”, “processing”, and “output”. 
     [input] R [processing] R [output] 
     [controller] R [model] R [view] 
     The MVC paradigm separately handles modeling of external data, visual feedback for the user, and input from the user, using a model object (M), a view object (V), and a controller object (C). The controller object analyzes the input from the user input via a mouse and a keyboard, and maps such user actions to a command to be transmitted to the model object and/or the view object. The model object operates so as to manage one or more data elements. Furthermore, the model object makes a response to a query with respect to the state of the data elements, and operates in response to an instruction to change the state of the data elements. The view object has a function of presenting data to the user in the form of a combination of graphics and text. 
     B. Overall Configuration of the Document Processing System 
     In order to make clear an embodiment of the document processing system, description will be made with reference to  FIGS. 11 through 29 . 
       FIG. 11(   a ) shows an example of a configuration comprising components that provide the basic functions of a kind of document processing system according to a conventional technique as will be mentioned later. A configuration  10  includes a processor in the form of a CPU or a microprocessor  11  connected to memory  12  via a communication path  13 . The memory  12  may be provided in the form of any kind of ROM and/or RAM that is currently available or that may be available in the future. In a typical case, the communication path  13  is provided in the form of a bus. An input/output interface  16  for user input devices such as a mouse, a keyboard, a speech recognition system, etc., and a display device  15  (or other user interfaces) is connected to the bus that provides communication with the processor  11  and the memory  12 . Such a configuration may be provided in the form of a standalone device. Also, such a configuration may be provided in the form of a network which includes multiple terminals and one or more servers connected to one another. Also, such a configuration may be provided in any known form. The present invention is not restricted to a particular layout of the components, a particular architecture, e.g., a centralized architecture or a distributed architecture, or a particular one of various methods of communication between the components. 
     Furthermore, description will be made below regarding the present system and the embodiment regarding an arrangement including several components and sub-components that provide various functions. In order to provide desired functions, the components and the sub-components can be realized by hardware alone, or by software alone, in addition to various combinations of hardware and software. Furthermore, the hardware, the software, and the various combinations thereof can be realized by general purpose hardware, dedicated hardware, or various combinations of general purpose and dedicated hardware. Accordingly, the configuration of the component or the sub-component includes a general purpose or dedicated computation device for executing predetermined software that provides a function required for the component or the sub-component. 
       FIG. 11(   b ) is a block diagram which shows an overall configuration of an example of the document processing system. Such a document processing system allows a document to be created and edited. Such a document may be described in a desired language that has the functions required of a markup language, such as XML etc. Note that some terms and titles will be defined here for convenience of explanation. However, the general scope of the disclosure according to the present invention is not intended to be restricted by such terms and titles thus defined here. 
     The document processing system can be classified into two basic configurations. A first configuration is an “execution environment”  101  which provides an environment that allows the document processing system to operate. For example, the execution environment provides basic utilities and functions that support both the system and the user during the processing and management of a document. A second configuration is an “application”  102  that comprises applications that run under an execution environment. These applications include the documents themselves and various representations of the documents. 
     1. Execution Environment 
     The key component of the execution environment  101  is the ProgramInvoker (program invoking unit)  103 . The ProgramInvoker  103  is a basic program, which is accessed in order to start up the document processing system. For example, upon the user logging on and starting up the document processing system, the ProgramInvoker  103  is executed. The ProgramInvoker  103  has: a function of reading out and executing a function added to the document processing system in the form of a plug-in; a function of starting up and executing an application; and a function of reading out the properties related to a document, for example. However, the functions of the ProgramInvoker  103  are not restricted to these functions. Upon the user giving an instruction to start up an application to be executed under the execution environment, the ProgramInvoker  103  finds and starts up the application, thereby executing the application. 
     Also, several components are attached to the ProgramInvoker  103 , examples of which include a plug-in sub-system  104 , a command sub-system  105 , and a resource module  109 . Detailed description will be made below regarding the configurations of such components. 
     a) Plug-In Sub-System 
     The plug-in sub-system is used as a highly flexible and efficient configuration which allows an additional function to be added to the document processing system. Also, the plug-in sub-system  104  can be used for modifying or deleting functions included in the document processing system. Also, various kinds of functions can be added or modified using the plug-in sub-system. For example, the plug-in sub-system  104  allows an Editlet (editing unit) to be added, which supports functions of allowing the user to edit via the screen. Also, the Editlet plug-in supports the functions of allowing the user to edit a vocabulary added to the system. 
     The plug-in sub-system  104  includes a ServiceBroker (service broker unit)  1041 . The ServiceBroker  1041  manages a plug-in added to the document processing system, thereby mediating between the service thus added and the document processing system. 
     Each of the desired functions is added in the form of a Service  1042 . Examples of the available types of Services  1042  include: an Application Service; a ZoneFactory (zone creating unit) Service; an Editlet (editing unit) Service; a CommandFactory (command creating unit) Service; a ConnectXPath (XPath management unit) Service; a CSSComputation (CSS calculation unit) Service; etc. However, the Service  1042  is not restricted to such services. Detailed description will be made below regarding these Services, and regarding the relation between these Services and other components of the system, in order to facilitate understanding of the document processing system. 
     Description will be made below regarding the relation between a plug-in and a Service. The plug-in is a unit capable of including one or more ServiceProviders (service providing units). Each ServiceProvider has one or more classes for corresponding Services. For example, upon using a plug-in having an appropriate software application, one or more Services are added to the system, thereby adding the corresponding functions to the system. 
     b) Command Sub-System 
     The command sub-system  105  is used for executing a command relating to the processing of a document. The command sub-system  105  allows the user to execute the processing of the document by executing a series of commands. For example, the command sub-system  105  allows the user to edit an XML DOM tree that corresponds to an XML document stored in the document processing system, and to process the XML document, by issuing a command. These commands may be input by key-strokes, mouse-clicks, or actions via other valid user interfaces. In some cases, when a single command is input, one or more sub-commands are executed. In such a case, these sub-commands are wrapped in a single command, and the sub-commands are consecutively executed. For example, let us consider a case in which the user has given an instruction to replace an incorrect word with a correct word. In this case, a first sub-command is an instruction to detect an incorrect word in the document. Then, a second sub-command is an instruction to delete the incorrect word. Finally, a third function is an instruction to insert a correct word. These three sub-commands may be wrapped in a single command. 
     Each command may have a corresponding function, e.g., an “undo” function described later in detail. Such a function may also be assigned to several basic classes used for creating an object. 
     The key component of the command sub-system  105  is a CommandInvoker (command invoking unit)  1051  which operates so as to allow the user to selectively input and execute the commands.  FIG. 11(   b ) shows an arrangement having a single CommandInvoker. Also, one or more CommandInvokers may be used. Also, one or more commands may be executed at the same time. The CommandInvoker  1051  holds the functions and classes required for executing the command. In the operation, the Command  1052  is loaded in a Queue  1053 . Then, the CommandInvoker  1051  creates a command thread for executing the commands in sequence. In a case that no Command is currently being executed by the CommandInvoker, the Command  1052  provided to be executed by the CommandInvoker  1051  is executed. In a case that a command is currently being executed by the CommandInvoker, the new Command is placed at the end of the Queue  1053 . However, each CommandInvoker  1051  executes only a single command at a time. In a case of failure in executing the Command thus specified, the CommandInvoker  1051  performs exception handling. 
     Examples of the types of Commands executed by the CommandInvoker  1051  include: an UndoableCommand (undoable command)  1054 ; an AsynchronousCommand (asynchronous command)  1055 ; and a VCCommand (VC command)  1056 . However, the types of commands are not restricted to those examples. The UndoableCommand  1054  is a command which can be undone according to an instruction from the user. Examples of UndoableCommands include a deletion command, a copy command, a text insertion command, etc. Let us consider a case in which, in the course of operation, the user has selected a part of a document, following which the deletion command is applied to the part thus selected. In this case, the corresponding UndoableCommand allows the deleted part to be restored to the state that it was in before the part was deleted. 
     The VCCommand  1056  is stored in a Vocabulary Connection Descriptor (VCD) script file. The VCCommand  1056  is a user specified Command defined by a programmer. Such a Command may be a combination of more abstract Commands, e.g., a Command for adding an XML fragment, a Command for deleting an XML fragment, a Command for setting an attribute, etc. In particular, such Commands are provided with document editing in mind. 
     The AsynchronousCommand  1055  is a command primarily provided for the system, such as a command for loading a document, a command for storing a document, etc. AsynchronousCommands  1055  are executed in an asynchronous manner, independently of UndoableCommands and VCCommands. Note that the AsynchronousCommand does not belong to the class of undoable commands (it is not an UndoableCommand). Accordingly, an AsynchronousCommand cannot be undone. 
     c) Resource 
     The Resource  109  is an object that provides several functions to various classes. Examples of such system Resources include string resources, icon resources, and default key bind resources. 
     2. Application Component 
     The application component  102 , which is the second principal component of the document processing system, is executed under the execution environment  101 . The application component  102  includes actual documents and various kinds of logical and physical representations of the documents included in the system. Furthermore, the application component  102  includes the configuration of the system used for management of the documents. The application component  102  further includes a UserApplication (user application)  106 , an application core  108 , a user interface  107 , and a CoreComponent (core component)  110 . 
     a) User Application 
     The UserApplication  106  is loaded in the system along with the ProgramInvoker  103 . The UserApplication  106  serves as a binding agent that connects a document, the various representations of the document, and the user interface required for communicating with the document. For example, let us consider a case in which the user creates a document set which is a part of a project. Upon loading the document set, an appropriate representation of the document is created. The user interface function is added as a part of the UserApplication  106 . In other words, with regard to a document that forms a part of a project, the UserApplication  106  holds both the representation of the document that allows the user to communicate with the document, and various other document conditions. Once the UserApplication  106  has been created, such an arrangement allows the user to load the UserApplication  106  under the execution environment in a simple manner every time there is a need to communicate with a document that forms a part of a project. 
     b) Core Component 
     The CoreComponent  110  provides a method which allows a document to be shared over multiple panes. As described later in detail, the Pane displays a DOM tree, and provides a physical screen layout. For example, a physical screen is formed of multiple Panes within a screen, each of which displays a corresponding part of the information. With such an arrangement, a document displayed on the screen for the user can be displayed in one or more Panes. Also, two different documents may be displayed on the screen in two different Panes. 
     As shown in  FIG. 11(   c ), the physical layout of the screen is provided in a tree form. The Pane can be a RootPane (root pane)  1084 . Also, the Pane can be a SubPane (sub-pane)  1085 . The RootPane  1084  is a Pane which is positioned at the root of a Pane tree. The SubPanes  1085  are other Panes that are distinct from the RootPane  1084 . 
     The CoreComponent  110  provides a font, and serves as a source that provides multiple functional operations for a document. Examples of the tasks executed by the CoreComponent  110  include movement of a mouse cursor across the multiple Panes. Other examples of the tasks thus executed include a task whereby a part of the document displayed on a Pane is marked, and the part thus selected is duplicated on another Pane. 
     c) Application Core 
     As described above, the application component  102  has a structure that comprises documents to be processed and managed by the system. Furthermore, the application component  102  includes various kinds of logical and physical representations of the documents stored in the system. The application core  108  is a component of the application component  102 . The application core  108  provides a function of holding an actual document along with all the data sets included in the document. The application core  108  includes a DocumentManager (document manager, document managing unit)  1081  and a Document (document)  1082  itself. 
     Detailed description will be made regarding various embodiments of the DocumentManager  1081 . The DocumentManager  1081  manages the Document  1082 . The DocumentManager  1081  is connected to the RootPane  1085 , the SubPane  1085 , a ClipBoard (clipboard) utility  1087 , and a SnapShot (snapshot) utility  1088 . The ClipBoard utility  1087  provides a method for holding a part of the document which is selected by the user as a part to be added to the clipboard. For example, let us consider a case in which the user deletes a part of a document, and stores the part thus deleted in a new document as a reference document. In this case, the part thus deleted is added to the ClipBoard. 
     Next, description will also be made regarding the SnapShot utility  1088 . The SnapShot utility  1088  allows the system to store the current state of an application before the state of the application changes from one particular state to another state. 
     d) User Interface 
     The user interface  107  is another component of the application component  102 , which provides a method that allows the user to physically communicate with the system. Specifically, the user interface allows the user to upload, delete, edit, and manage a document. The user interface includes a Frame (frame)  1071 , a MenuBar (menu bar)  1072 , a StatusBar (status bar)  1073 , and a URLBar (URL bar)  1074 . 
     The Frame  1071  serves as an active region of a physical screen, as is generally known. The Menubar  1072  is a screen region including a menu that provides selections to the user. The StatusBar  1073  is a screen region that displays the status of the application which is being executed. The URLBar  1074  provides a region which allows the user to input a URL address for Internet navigation. 
     C. Document Management and Corresponding Data Structure 
       FIG. 12  shows a configuration of the DocumentManager  1081  in detail. The DocumentManager  1081  includes a data structure and components used for representing a document in the document processing system. Description will be made regarding such components in this sub-section using the MVC paradigm for convenience of explanation. 
     The DocumentManager  1081  includes a DocumentContainer (document container)  203  which holds all the documents stored in the document processing system, and which serves as a host machine. A tool kit  201  attached to the DocumentManager  1081  provides various tools used by the DocumentManager  1081 . For example, the tool kit  201  provides a DomService (DOM service) which provides all the functions required for creating, holding, and managing a DOM that corresponds to a document. Also, the tool kit  201  provides an IOManager (input/output management unit) which is another tool for managing the input to/output from the system. Also, a StreamHandler (stream handler) is a tool for handling uploading a document in the form of a bit stream. The tool kit  201  includes such tools in the form of components, which are not shown in the drawings in particular, and are not denoted by reference numerals. 
     With the system represented using the MVC paradigm, the model (M) includes a DOM tree model  202  of a document. As described above, each of all the documents is represented by the document processing system in the form of a DOM tree. Also, the document forms a part of the DocumentContainer  203 . 
     1. DOM Model and Zone 
     The DOM tree which represents a document has a tree structure having Nodes (Nodes)  2021 . A Zone (zone)  209 , which is a subset of the DOM tree, includes a region that corresponds to one or more Nodes within the DOM tree. For example, a part of a document can be displayed on a screen. In this case, the part of the document that is visually output is displayed using the Zone  209 . The Zone is created, handled, and processed using a plug-in which is so-called ZoneFactory (Zone Factory=Zone creating unit)  205 . While the Zone represents a part of the DOM, the Zone can use one or more “namespaces”. It is well known that a namespace is a set that consists of unique names, each of which differs from every other name in the namespace. In other words, the namespace does not include the same names repeated. 
     2. Facets and the Relation Between Facets and Zones 
     A Facet  2022  is another component included in the model (M) component of the MVC paradigm. The Facet is used for editing the Node in the Zone. The Facet  2022  allows the user to access the DOM using a procedure that can be executed without affecting the content of the Zone. As described below, such a procedure executes an important and useful operation with respect to the Node. 
     Each Node has a corresponding Facet. With such an arrangement, the facet is used for executing the operation instead of directly operating the Node in the DOM, thereby maintaining the integrity of the DOM. On the other hand, let us consider an arrangement in which an operation is performed directly on the Node. With such an arrangement, multiple plug-ins can change the DOM at the same time, leading to a problem that the integrity of the DOM cannot be maintained. 
     The DOM standard stipulated by the World Wide Web Consortium (W3C) defines a standard interface for operating a Node. In practice, unique operations particular to each vocabulary or each Node are required. Accordingly, such unique operations are preferably provided in the form of an API. The document processing system provides such an API particular to each Node in the form of a Facet which is attached to the Node. Such an arrangement allows a useful API to be attached to the DOM according to the DOM standard. Furthermore, with such an arrangement, after a standard DOM has been installed, unique APIs are attached to the DOM, instead of installing a unique DOM for each vocabulary. This allows various kinds of vocabularies to be uniformly handled. Furthermore, such an arrangement allows the user to properly process a document described using a desired combination of multiple vocabularies. 
     Each vocabulary is a set of tags (e.g., XML tags), which belong to a corresponding namespace. As described above, each namespace has a set of unique names (in this case, tags). Each vocabulary is handled as a sub-tree of the DOM tree which represents an XML document. The sub-tree includes the Zone. In particular cases, the boundary between the tag sets is defined by the Zone. The Zone  209  is created using a Service which is called a ZoneFactory  205 . As described above, the Zone  209  is an internal representation of a part of the DOM tree which represents a document. In order to provide a method that allows the user to access a part of such a document, the system requires a logical representation of the DOM tree. The logical representation of the DOM allows the computer to be informed of how the document is logically represented on a screen. A Canvas (canvas)  210  is a Service that operates so as to provide a logical layout that corresponds to the Zone. 
     On the other hand, a Pane  211  is a physical screen layout that corresponds to a logical layout provided by the Canvas  210 . In practice, the user views only a rendering of the document, through text or images displayed on a screen. Accordingly, there is a need to use a process for drawing text and images on a screen to display the document on a screen. With such an arrangement, the document is displayed on a screen by the Canvas  210  based upon the physical layout provided from the Pane  211 . 
     The Canvas  210  that corresponds to the Zone  209  is created using an Editlet  206 . The DOM of the document is edited using the Editlet  206  and the Canvas  210 . In order to maintain the integrity of the original document, the Editlet  206  and the Canvas  210  use the Facet that corresponds to one or more Nodes included in the Zone  209 . The Facet is operated using a Command  207 . 
     In general, the user communicates with a screen by moving a cursor on a screen or typing a command. The Canvas  210 , which provides a logical layout on a screen, allows the user to input such cursor operations. The Canvas  210  instructs the Facet to execute a corresponding action. With such a relation, the cursor sub-system  204  serves as a controller (C) according to the MVC paradigm with respect to the DocumentManager  1081 . The Canvas  210  also provides a task for handling an event. Examples of such events handled by the canvas  210  include: a mouse click event; a focus movement event; and a similar action event occurring in response to the user operation. 
     3. Outline of the Relation Between Zone, Facet, Canvas, and Pane. 
     The document in the document processing system can be described from at least four points of view. That is to say, it can be seen as: 1) a data structure for maintaining the content and structure of a document in the document processing system, 2) means by which the user can edit the content of the document while maintaining the integrity of the document, 3) a logical layout of the document on a screen, and 4) a physical layout of the document on the screen. The components of the document processing system that correspond to the aforementioned four points of view are the Zone, Facet, Canvas, and Pane, respectively. 
     4. Undo Sub-System 
     As described above, all modifications made to the document (e.g., document editing procedures) are preferably undoable. For example, let us consider a case in which the user executes an editing operation, and then determines that the modification thus made to the document should be undone. Referring to  FIG. 12 , the undo subsystem  212  provides an undo component of a document management unit. With such an arrangement, an UndoManager (undo manager=undo management unit)  2121  holds all the undoable operations for the document which the user can select to be undone. 
     Let us consider a case in which the user executes a command for replacing a word in a document by another word, following which the user determines that, on reflection, the replacement of the word thus effected should be undone. The undo sub-system supports such an operation. The UndoManager  2121  holds such an operation of an UndoableEdit (undoable edit)  2122 . 
     5. Cursor Sub-System 
     As described above, the controller unit of the MVC may include the cursor sub-system  204 . The cursor sub-system  204  receives the input from the user. In general, such an input provides command input and/or edit operation. Accordingly, with respect to the DocumentManager  1081 , the cursor sub-system  204  serves as the controller (C) component according to the MVC paradigm. 
     6. View 
     As described above, the Canvas  210  represents the logical layout of a document to be displayed on a screen. In a case that the document is an XHTML document, the Canvas  210  may include a box tree  208  that provides a logical representation of a document, which indicates how the document is displayed on a screen. With respect to the DocumentManager  1081 , the box tree  208  may be included in the view (V) component according to the MVC paradigm. 
     D. Vocabulary Connection 
     The important feature of the document processing system is that the document processing system provides an environment which allows the user to handle an XML document via other representations to which the document has been mapped. With such an environment, upon the user editing a representation to which the source XML document has been mapped, the source XML document is modified according to the edit operation while maintaining the integrity of the XML document. 
     A document described in a markup language, e.g., an XML document is created based upon a vocabulary defined by a document type definition. The vocabulary is a set of tags. The vocabulary can be defined as desired. This allows a limitless number of vocabularies to be created. It does not serve any practical purpose to provide dedicated viewer/editor environments for such a limitless number of vocabularies. The vocabulary connection provides a method for solving this problem. 
     For example, a document can be described in two or more markup languages. Specific examples of such markup languages used for describing a document include: XHTML (eXtensible HyperText Markup Language), SVG (Scalable Vector Graphics), MathML (Mathematical Markup Language), and other markup languages. In other words, such a markup language can be handled in the same way as is the vocabulary or the tag set in XML. 
     A vocabulary is processed using a vocabulary plug-in. In a case that the document has been described in a vocabulary for which there is no available plug-in in the document processing system, the document is mapped to a document described in another vocabulary for which a plug-in is available, thereby displaying the document. Such a function enables a document to be properly displayed even if the document has been described in a vocabulary for which there is no available plug-in. 
     The vocabulary connection has a function of acquiring a definition file, and a function of mapping from one vocabulary to another different vocabulary based upon the definition file thus acquired. With such an arrangement, a document described in one vocabulary can be mapped to a document described in another vocabulary. As described above, the vocabulary connection maps a document described in one vocabulary to another document described in another vocabulary for which there is a corresponding display/editing plug-in, thereby allowing the user to display and edit the document. 
     As described above, in general, each document is described by the document processing system in the form of a DOM tree having multiple Nodes. The “definition file” describes the relations among the different Nodes. Furthermore, the definition file specifies whether or not the element values and the attribute values can be edited for each Node. Also, the definition file may specify an expression using the element values and the attribute values of the Nodes. 
     Using the mapping function by applying the definition file, a destination DOM tree can be created. As described above, the relation between the source DOM tree and the destination DOM tree is created and held. The vocabulary connection monitors the relation between the source DOM tree and the destination DOM tree. Upon reception of an editing instruction from the user, the vocabulary connection modifies the corresponding Node included in the source DOM tree. Subsequently, a “mutation event” is issued, which gives notice that the source DOM tree has been modified. Then, the destination DOM tree is modified in response to the mutation event. 
     The use of the vocabulary connection allows a relatively minor vocabulary used by a small number of users to be converted into another major vocabulary. Thus, such an arrangement provides a desirable editing environment, which allows a document to be properly displayed even if the document is described in a minor vocabulary used by a small number of users. 
     As described above, the vocabulary connection sub-system which is a part of the document processing system provides a function that allows a document to be represented in multiple different ways. 
       FIG. 13  shows a vocabulary connection (VC) sub-system  300 . The VC sub-system  300  provides a method for representing a document in two different ways while maintaining the integrity of the source document. For example, a single document may be represented in two different ways using two different vocabularies. Also, one representation may be a source DOM tree, and the other representation may be a destination DOM tree, as described above. 
     1. Vocabulary Connection Sub-System 
     The functions of the vocabulary connection sub-system  300  are provided to the document processing system using a plug-in which is called a VocabularyConnection  301 . With such an arrangement, a corresponding plug-in is requested for each Vocabulary  305  used for representing the document. For example, let us consider a case in which a part of the document is described in HTML, and the other part is described in SVG. In this case, the vocabulary plug-in that corresponds to HTML and the vocabulary plug-in that corresponds to SVG are requested. 
     The VocabularyConnection plug-in  301  creates a proper VCCanvas (vocabulary connection canvas)  310  that corresponds to a document described in a properVocabulary  305  for the Zone  209  or the Pane  211 . Using the VocabularyConnection  301 , a modification made to the Zone  209  within the source DOM tree is transmitted to the corresponding Zone within another DOM tree  306  according to a conversion rule. The conversion rule is described in the form of a vocabulary connection descriptor (VCD). Furthermore, a corresponding VCManager (vocabulary connection manager)  302  is created for each VCD file that corresponds to such a conversion between the source DOM and the destination DOM. 
     2. Connector 
     A Connector  304  connects the source Node included within the source DOM tree and the destination Node included within the destination DOM tree. The Connector  304  operates so as to monitor modifications (changes) made to the source Node included within the source DOM tree and the source document that corresponds to the source Node. Then, the Connector  304  modifies the corresponding Node of the destination DOM tree. With such an arrangement, the Connector  304  is the only object which is capable of modifying the destination DOM tree. Specifically, the user can modify only the source document and the corresponding source DOM tree. With such an arrangement, the Connector  304  modifies the destination DOM tree according to the modification thus made by the user. 
     The Connectors  304  are logically linked to each other so as to form a tree structure. The tree structure formed of the Connectors  304  is referred to as a ConnectorTree (connector tree). The connector  304  is created using a Service which is called a ConnectorFactory (connector factory=connector generating unit)  303 . The ConnectorFactory  303  creates the Connectors  304  based upon a source document, and links the Connectors  304  to each other so as to create a ConnectorTree. The VocabularyConnectionManager  302  holds the ConnectorFactory  303 . 
     As described above, a vocabulary is a set of tags for a namespace. As shown in the drawing, the VocabularyConnection  301  creates the Vocabulary  305  for a document. Specifically, the Vocabulary  305  is created by analyzing the document file, and then creating a proper VocabularyConnectionManager  302  for mapping between the source DOM and the destination DOM. Furthermore, a proper relation is created between the ConnectorFactory  303  for creating the Connectors, the ZoneFactory  205  for creating the Zones  209 , and the Editlet  206  for creating the Canvases. In a case that the user has discarded or deleted a document stored in the system, the corresponding VocabularyConnectionManager  302  is deleted. 
     The Vocabulary  305  creates the VCCanvas  310 . Furthermore, the connectors  304  and the destination DOM tree  306  are created corresponding to the creation of the VCCanvas  310 . 
     The source DOM and the Canvas correspond to the Model (M) and the View (V), respectively. However, such a representation is useful only in a case that the target vocabulary allows a document to be displayed on a screen. With such an arrangement, the display is performed by the vocabulary plug-in. Such a Vocabulary plug-in is provided for each of the principal vocabularies, e.g., XHTML, SVG, and MathML. Such a vocabulary plug-in is used for the target vocabulary. Such an arrangement provides a method for mapping a vocabulary to another vocabulary using a vocabulary connection descriptor. 
     Such mapping is useful only in a case that the target vocabulary can be mapped, and a method has been defined beforehand for displaying such a document thus mapped on a screen. Such a rendering method is defined in the form of a standard defined by an authority such as the W3C. 
     In a case that the processing requires vocabulary connection, the VCCanvas is used. In this case, the view for the source cannot be directly created, and accordingly, the Canvas for the source is not created. In this case, the VCCanvas is created using the ConnectorTree. The VCCanvas handles only the conversion of the event, but does not support display of the document on a screen. 
     3. DestinationZone, Pane, and Canvas 
     As described above, the purpose of the vocabulary connection sub-system is to create and hold two representations of a single document at the same time. With such an arrangement, the second representation is provided in the form of a DOM tree, which has been described as the destination DOM tree. The display of the document in the form of the second representation requires the DestinationZone, Canvas, and Pane. 
     When the VCCanvas is created, a corresponding DestinationPane  307  is also created. Furthermore, a corresponding DestinationCanvas  308  and a corresponding BoxTree  309  are created. Also, the VCCanvas  310  is associated with the Pane  211  and the Zone  209  for the source document. 
     The DestinationCanvas  308  provides a logical layout of a document in the form of the second representation. Specifically, the DestinationCanvas  308  provides user interface functions such as a cursor function and a selection function, for displaying a document in the form of a destination representation of the document. The event occurring at the DestinationCanvas  308  is supplied to the Connector. The DestinationCanvas  308  notifies the Connector  304  of the occurrence of a mouse event, a keyboard event, a drag-and-drop event, and events particular to the destination representation (second representation). 
     4. Vocabulary Connection Command Sub-System 
     The vocabulary connection (VC) sub-system  300  includes a vocabulary connection (VC) command sub-system  313  in the form of a component. The vocabulary connection command sub-system  313  creates a VCCommand (vocabulary connection command)  315  used for executing a command with respect to the vocabulary connection sub-system  300 . The VCCommand can be created using a built-in CommandTemplate (command template) and/or created from scratch using a script language supported by a script sub-system  314 . 
     Examples of such command templates include an “If” command template, “When” command template, “Insert” command template, etc. These templates are used for creating a VCCommand. 
     5. XPath Sub-System 
     An XPath sub-system  316  is an important component of the document processing system, and supports the vocabulary connection. In general, the Connector  304  includes XPath information. As described above, one of the tasks of the vocabulary connection is to modify the destination DOM tree according to the change in the source DOM tree. The XPath information includes one or more XPath representations used for determining a subset of the source DOM tree which is to be monitored to detect changes and/or modifications. 
     6. Outline of Source DOM Tree, Destination DOM Tree, and ConnectorTree 
     The source DOM tree is a DOM tree or a Zone of a document described in a vocabulary before vocabulary conversion. The source DOM tree Node is referred to as the source Node. 
     On the other hand, the destination DOM tree is a DOM tree or a Zone of the same document as that of the source DOM tree, and which is described in another vocabulary after having been converted by mapping, as described above in connection with the vocabulary connection. Here, the destination DOM tree Node is referred to as the destination Node. 
     The ConnectorTree is a hierarchical representation which is formed based upon the Connectors that represent the relation between the source Nodes and the destination Nodes. The Connectors monitor the source Node and the modifications applied to the source document, and modify the destination DOM tree. The Connector is the only object that is permitted to modify the destination DOM tree. 
     E. Event Flow in the Document Processing System 
     In practice, the program needs to respond to the commands input from the user. The “event” concept provides a method for describing and executing the user action executed on a program. Many high-level languages, e.g., Java (trademark) require events, each of which describes a corresponding user action. On the other hand, conventional programs need to actively collect information for analyzing the user&#39;s actions, and for execution of the user&#39;s actions by the program itself. This means that, after initialization of the program, the program enters loop processing for monitoring the user&#39;s actions, which enables appropriate processing to be performed in response to any user action input by the user via the screen, keyboard, mouse, or the like. However, such a process is difficult to manage. Furthermore, such an arrangement requires a program which performs loop processing in order to wait for the user&#39;s actions, leading to a waste of CPU cycles. 
     Many languages employ distinctive paradigms in order to solve such problems. One of these paradigms is event-driven programming, which is employed as the basis of all current window-based systems. In this paradigm, all user actions belong to sets of abstract phenomena which are called “events”. An event provides a sufficiently detailed description of a corresponding user action. With such an arrangement, in a case that an event to be monitored has occurred, the system notifies the program to that effect, instead of an arrangement in which the program actively collects events occurring according to the user&#39;s actions. A program that communicates with the user using such a method is referred to as an “event-driven” program. 
     In many cases, such an arrangement handles an event using a “Event” class that acquires the basic properties of all the events which can occur according to the user&#39;s actions. 
     Before the use of the document processing system, the events for the document processing system itself and a method for handling such events are defined. With such an arrangement, several types of events are used. For example, a mouse event is an event that occurs according to the action performed by the user via a mouse. The user action involving the mouse is transmitted to the mouse event by the Canvas  210 . As described above, it can be said that the Canvas is the foremost level of interaction between the user and the system. As necessary, this foremost Canvas level hands over the event content to the child levels. 
     On the other hand, a keystroke event is issued from the Canvas  210 . The keystroke event acquires a real-time focus. That is to say, a keystroke event always involves an operation. The keystroke event input to the Canvas  210  is also transmitted to the parent of the Canvas  210 . Key input actions are processed via other events that allow the user to insert a character string. The event for handling the insertion of a character string occurs according to the user action in which a character is input via the keyboard. Examples of “other events” include other events which are handled in the same way as a drag event, a drop event, and a mouse event. 
     1. Handling of an Event Outside of the Vocabulary Connection 
     An event is transmitted using an event thread. The state of the Canvas  210  is modified upon reception of an event. As necessary, the Canvas  210  posts the Command  1052  to the CommandQueue  1053 . 
     2. Handling of an Event Within the Vocabulary Connection 
     An XHTMLCanvas  1106 , which is an example of the DestinationCanvas, receives events that occur, e.g., a mouse event, a keyboard event, a drag-and-drop event, and events particular to the vocabulary, using the VocabularyConnection plug-in  301 . The connector  304  is notified of these events. More specifically, the event passes through a SourcePane  1103 , a VCCanvas  1104 , a DestinationPane  1105 , a DestinationCanvas  1106  which is an example of the DestinationCanvas, a destination DOM tree, and a ConnectorTree, within the VocabularyConnection plug-in, as shown in  FIG. 21(   b ). 
     F. ProgramInvoker and the Relation Between ProgramInvoker and Other Components 
       FIG. 14(   a ) shows the ProgramInvoker  103  and the relation between the ProgramInvoker  103  and other components in more detail. The ProgramInvoker  103  is a basic program executed under the execution environment, which starts up the document processing system. As shown in  FIG. 11(   b ) and  FIG. 11(   c ), the UserApplication  106 , the ServiceBroker  1041 , the CommandInvoker  1051 , and the Resource  109  are each connected to the ProgramInvoker  103 . As described above, the application  102  is a component executed under the execution environment. Also, the ServiceBroker  1041  manages the plug-ins, which provide various functions to the system. On the other hand, the CommandInvoker  1051  executes a command provided from the user, and holds the classes and functions for executing the command. 
     1. Plug-In and Service 
     A more detailed description will be made regarding the ServiceBroker  1041  with reference to  FIG. 14(   b ). As described above, the ServiceBroker  1041  manages the plug-ins (and corresponding services), which allows various functions to be added to the system. The Service  1042  is the lowermost layer, having a function of adding the features to the document processing system, and a function of modifying the features of the document processing system. A “Service” consists of two parts, i.e., a part formed of ServiceCategories  401  and another part formed of ServiceProviders  402 . As shown in  FIG. 14(   c ), one ServiceCategory  401  may include multiple corresponding ServiceProviders  402 . Each ServiceProvider operates a part of, or the entire functions of, the corresponding ServiceCategory. Also, the ServiceCategory  401  defines the type of Service. 
     The Services can be classified into three types, i.e., a “feature service” which provides predetermined features to the document processing system, an “application service” which is an application executed by the document processing system, and an “environment” service that provides the features necessary throughout the document processing system. 
       FIG. 14(   d ) shows an example of a Service. In this example, with respect to the Category of the application Service, the system utility corresponds to the ServiceProvider. In the same way, the Editlet  206  is the Category, and an HTMLEditlet and the SVGEditlet are the corresponding ServiceProviders. Also, the ZoneFactory  205  is another Service Category, and has a corresponding ServiceProvider (not shown). 
     As described above, a plug-in adds functions to the document processing system. Also, a plug-in can be handled as a unit that comprises several ServiceProviders  402  and the classes that correspond to the ServiceProviders  402 . Each plug-in has dependency specified in the definition file and a ServiceCategory  401 . 
     2. Relation Between the ProgramInvoker and the Application 
       FIG. 14(   e ) shows the relation between the ProgramInvoker  103  and the UserApplication  106  in more detail. The required documents and data are loaded from the storage. All the required plug-ins are loaded in the ServiceBroker  1041 . The ServiceBroker  1041  holds and manages all the plug-ins. Each plug-in is physically added to the system. Also, the functions of the plug-in can be loaded from the storage. When the content of a plug-in is loaded, the ServiceBroker  1041  defines the corresponding plug-in. Subsequently, a corresponding UserApplication  106  is created, and the UserApplication  106  thus created is loaded in the execution environment  101 , thereby attaching the plug-in to the ProgramInvoker  103 . 
     G. The Relation Between the Application Service and the Environment 
       FIG. 15(   a ) shows the configuration of the application service loaded in the ProgramInvoker  103  in more detail. The CommandInvoker  1051 , which is a component of the command sub-system  105 , starts up or executes the Command  1052  in the ProgramInvoker  103 . With such a document processing system, the Command  1052  is a command used for processing a document such as an XML document, and editing the corresponding XML DOM tree. The CommandInvoker  1051  holds the classes and functions required to execute the Command  1052 . 
     Also, the ServiceBroker  1041  is executed within the ProgramInvoker  103 . The UserApplication  106  is connected to the user interface  107  and the CoreComponent  110 . The CoreComponent  110  provides a method which allows all the Panes to share a document. Furthermore, the CoreComponent  110  provides a font, and serves as a tool kit for the Pane. 
       FIG. 15(   b ) shows the relation between the Frame  1071 , the MenuBar  1072 , and the StatusBar  1073 . 
     H. Application Core 
       FIG. 16(   a ) provides a more detailed description of the application core  108 , which holds the whole document, and a part of the document, and the data of the document. The CoreComponent  110  is attached to the DocumentManager  1081  for managing the documents  1082 . The DocumentManager  1081  is the owner of all the documents  1082  stored in memory in association with the document processing system. 
     In order to display a document on a screen in a simple manner, the DocumentManager  1081  is also connected to the RootPane  1084 . Also, the functions of the Clipboard  1087 , a Drag&amp;Drop  601 , and an Overlay  602  are attached to the CoreComponent  110 . 
     The SnapShot  1088  is used for restoring the application to a given state. Upon the user executing the SnapShot  1088 , the current state of the application is detected and stored. Subsequently, when the application state changes, the content of the application state thus stored is maintained.  FIG. 16(   b ) shows the operation of the SnapShot  1088 . With such an arrangement, upon the application switching from one URL to another, the SnapShot  1088  stores the previous state. Such an arrangement allows operations to be performed forward and backward in a seamless manner. 
     I. Document Structure within the DocumentManager 
       FIG. 17(   a ) provides a more detailed description of the DocumentManager  1081 , and shows the DocumentManager holding documents according to a predetermined structure. As shown in  FIG. 11(   b ), the DocumentManager  1081  manages the documents  1082 . With an example shown in  FIG. 17(   a ), one of the multiple documents is a RootDocument (root document)  701 , and the other documents are SubDocuments (sub-documents)  702 . The DocumentManager  1081  is connected to the RootDocument  701 . Furthermore, the RootDocument  701  is connected to all the SubDocuments  702 . 
     As shown in  FIG. 12  and  FIG. 17(   a ), the DocumentManager  1081  is connected to the DocumentContainer  203 , which is an object for managing all the documents  1082 . The tools that form a part of the tool kit  201  (e.g., XML tool kit) including a DOMService  703  and an IOManager  704  are supplied to the DocumentManager  1081 . Referring to  FIG. 17(   a ) again, the DOM service  703  creates a DOM tree based upon a document managed by the DocumentManager  1081 . Each document  705 , whether it is a RootDocument  701  or a SubDocument  702 , is managed by a corresponding DocumentContainer  203 . 
       FIG. 17(   b ) shows the documents A through E managed in a hierarchical manner. The document A is a RootDocument. On the other hand, the documents B through D are the SubDocuments of the document A. The document E is the SubDocument of the document D. The left side in  FIG. 17(   b ) shows an example of the documents displayed on a screen according to the aforementioned hierarchical management structure. In this example, the document A, which is the RootDocument, is displayed in the form of a base frame. On the other hand, the documents B through D, which are the SubDocuments of the document A, are displayed in the form of sub-frames included in the base frame A. On the other hand, the document E, which is the SubDocument of the document D, is displayed on a screen in the form of a sub-frame of the sub-frame D. 
     Referring to  FIG. 17(   a ) again, an UndoManager (undo manager=undo management unit)  706  and an UndoWrapper (undo wrapper)  707  are created for each DocumentContainer  203 . The UndoManager  706  and the UndoWrapper  707  are used for executing an undoable command. Such a feature allows the user to reverse a modification which has been applied to the document according to an editing operation. Here, the modification of the SubDocument significantly affects the RootDocument. The undo operation performed under such an arrangement gives consideration to the modification that affects other hierarchically managed documents, thereby preserving the document integrity over all the documents managed in a particular hierarchical chain, as shown in  FIG. 17(   b ), for example. 
     The UndoWrapper  707  wraps undo objects with respect to the SubDocuments stored in the DocumentContainer  203 . Then, the UndoWrapper  707  connects the undo objects thus wrapped to the undo object with respect to the RootDocument. With such an arrangement, the UndoWrapper  707  acquires available undo objects for an UndoableEditAcceptor (undoable edit acceptor=undoable edit reception unit)  709 . 
     The UndoManager  706  and the UndoWrapper  707  are connected to the UndoableEditAcceptor  709  and an UndoableEditSource (undoable edit source)  708 . Note that the Document  705  may be the UndoableEditSource  708  or a source of an undoable edit object, as can be readily understood by those skilled in this art. 
     J. Undo Command and Undo Framework 
       FIG. 18(   a ) and  FIG. 18(   b ) provide a more detailed description with respect to an undo framework and an undo command. As shown in  FIG. 18(   a ), an UndoCommand  801 , RedoCommand  802 , and an UndoableEditCommand  803  are commands that can be loaded in the CommandInvoker  1051 , and which are serially executed. The UndoableEditCommand  803  is further attached to the UndoableEditSource  708  and the UndoableEditAcceptor  709 . Examples of such undoableEditCommands include a “foo” EditCommand  804  and a “bar” EditCommand  805 . 
     1. Execution of UndoableEditCommand 
       FIG. 18(   b ) shows execution of the UndoableEditCommand. First, let us consider a case in which the user edits the Document  705  using an edit command. In the first step S 1 , the UndoableEditAcceptor  709  is attached to the UndoableEditSource  708  which is a DOM tree of the Document  705 . In the second step S 2 , the Document  705  is edited using an API for the DOM according to a command issued by the user. In the third step S 3 , a listener of the mutation event is notified of the modification. That is to say, in this step, the listener that monitors all modifications made to the DOM tree detects such an edit operation. In the fourth step S 4 , the UndoableEdit is stored as an object of the UndoManager  706 . In the fifth step S 5 , the UndoableEditAcceptor  709  is detached from the UndoableEditSource  708 . Here, the UndoableEditSource  708  may be the Document  705  itself. 
     K. Procedure for Loading a Document to the System 
     Description has been made in the aforementioned sub-sections regarding various components and sub-components of the system. Description will be made below regarding methods for using such components.  FIG. 19(   a ) shows the outline of the operation for loading a document to the document processing system. Detailed description will be made regarding each step with reference to examples shown in  FIGS. 24 through 28 . 
     In brief, the document processing system creates a DOM based upon the document data which is provided in the form of a binary data stream. First, an ApexNode (apex Node=top Node) is created for the targeted part of the document, which is a part of the document that belongs to the Zone. Subsequently, the corresponding Pane is identified. The Pane thus identified creates the Zone and Canvas from the ApexNode and the physical screen. Then, the Zone creates a Facet for each Node, and provides the necessary information to the Facets. On the other hand, the Canvas creates a data structure for rendering the Nodes based upon the DOM tree. 
     More specifically, the document is loaded from a storage  901 . Then, a DOM tree  902  of the document is created. Subsequently, a corresponding DocumentContainer  903  is created for holding the document. The DocumentContainer  903  is attached to the DocumentManager  904 . The DOM tree includes the root Node, and in some cases includes multiple secondary Nodes. 
     Such a document generally includes both text data and graphics data. Accordingly, the DOM tree may include an SVG sub-tree, in addition to an XHTML sub-tree. The XHTML sub-tree includes an ApexNode  905  for XHTML. In the same way, the SVG sub-tree includes an ApexNode  906  for SVG. 
     In Step  1 , the ApexNode  906  is attached to a Pane  907  which is a logical layout of the screen. In Step  2 , the Pane  907  issues a request for the CoreComponent which is the PaneOwner (pane owner=owner of the pane)  908  to provide a ZoneFactory for the ApexNode  906 . In Step  3 , in the form of a response, the PaneOwner  908  provides the ZoneFactory and the Editlet which is a CanvasFactory for the ApexNode  906 . 
     In Step  4 , the Pane  907  creates a Zone  909 . The Zone  909  is attached to the Pane  907 . In Step  5 , the Zone  909  creates a Facet for each Node, and attaches the Facets thus created to the respective Nodes. In Step  6 , the Pane  907  creates a Canvas  910 . The Canvas  910  is attached to the Pane  907 . The Canvas  910  includes various Commands. In Step  7 , the Canvas  910  creates a data structure for rendering the document on a screen. In a case of XHTML, the data structure includes a box tree structure. 
     1. MVC of the Zone 
       FIG. 19(   b ) shows the outline of a structure of the Zone using the MVC paradigm. In this case, with respect to a document, the Zone and the Facets are the input, and accordingly the model (M) includes the Zone and the Facets. On the other hand, the Canvas and the data structure for rendering a document on a screen are the output, in the form of an image displayed on a screen for the user. Accordingly, the view (V) corresponds to the Canvas and the data structure. The Command executes control operations for the document and the various components that correspond to the document. Accordingly, the control (C) includes the Commands included in the Canvas. 
     L. Representation of a Document 
     Description will be made below regarding an example of a document and various representations thereof. The document used in this example includes both text data and image data. The text data is represented using XHTML, and the image data is represented using SVG.  FIG. 20  shows in detail the relation between the components of the document and the corresponding objects represented in the MVC. In this example, a Document  1001  is attached to a DocumentContainer  1002  for holding the Document  1001 . The document is represented in the form of a DOM tree  1003 . The DOM tree includes an ApexNode  1004 . 
     The ApexNode is indicated by a solid circle. Each of the Nodes other than the ApexNode is indicated by an empty circle. Each Facet used for editing the Node is indicated by a triangle, and is attached to the corresponding Node. Here, the document includes text data and image data. Accordingly, the DOM tree of the document includes an XHTML component and an SVG component. The ApexNode  1004  is the top Node of the XHTML sub-tree. The ApexNode  1004  is attached to an XHTMLPane  1005  which is the top pane for physically representing the XHTML component of the document. Furthermore, the ApexNode  1004  is attached to an XHTMLZone  1006  which is a part of the DOM tree of the document. 
     Also, the Facet that corresponds to the Node  1004  is attached to the XHTMLZone  1006 . The XHTMLZone  1006  is attached to the XHTMLPane  1005 . The XHTMLEditlet creates a XHTMLCanvas  1007  which is a logical representation of the document. The XHTMLCanvas  1007  is attached to the XHTMLPane  1005 . The XHTMLCanvas  1007  creates a BoxTree  1009  for the XHTML component of the Document  1001 . Various commands  1008  necessary for holding and displaying the XHTML component of the document are added to the XHTMLCanvas  1007 . 
     In the same way, an ApexNode  1010  of the SVG sub-tree of the document is attached to an SVGZone  1011  which is a part of the DOM tree of the document  1001 , and which represents the SVG component of the document. The ApexNode  1010  is attached to an SVGPane  1013  which is the top Pane for physically representing the SVG part of the document. An SVGCanvas  1012  for logically representing the SVG component of the document is created by the SVGEditlet, and is attached to an SVGPane  1013 . The data structure and the commands for rendering the SVG component of the document on a screen are attached to the SVGCanvas. For example, this data structure may include circles, lines, and rectangles, and so forth, as shown in the drawing. 
     While description has been made regarding the representation of a document with reference to  FIG. 20 , further description will be made regarding a part of such examples of the representations of the document using the above-described MVC paradigm with reference to  FIG. 21(   a ).  FIG. 21(   a ) shows a simplified relation between M and V (MV) with respect to the XHTML components of the document  1001 . In this case, the model is the XHTMLZone  1101  for the XHTML component of the Document  1001 . The tree structure of the XHTMLZone includes several Nodes and the corresponding Facets. With such an arrangement, the corresponding XHTMLZone and the Pane are a part of the model (M) component of the MVC paradigm. On the other hand, the view (V) component of the MVC paradigm corresponds to the XHTMLCanvas  1102  and the BoxTree that correspond to the XHTML component of the Document  1001 . With such an arrangement, the XHTML component of the document is displayed on a screen using the Canvas and the Commands included in the Canvas. Note that the events occurring due to the keyboard action and the mouse input proceed in the opposite direction to that of the output. 
     The SourcePane provides an additional function, i.e., serves as a DOM owner.  FIG. 21(   b ) shows the operation in which the vocabulary connection is provided for the components of the Document  1001  shown in  FIG. 21(   a ). The SourcePane  1103  that serves as a DOM holder includes a source DOM tree of the document. The ConnectorTree is created by the ConnectorFactory, and creates the DestinationPane  1105  which also serves as an owner of the destination DOM. The DestinationPane  1105  is provided in the form of the XHTMLDestinationCanvas  1106  having a box tree layout. 
     M. The Relation Between Plug-In Sub-System, Vocabulary Connection, and Connector 
       FIGS. 22(   a ) through  22 ( c ) provide further detailed description with respect to the plug-in sub-system, the vocabulary connection, and the Connector, respectively. The Plug-in sub-system is used for adding a function to the document processing system or for replacing a function of the document processing system. The plug-in sub-system includes the ServiceBroker  1041 . A ZoneFactoryService  1201  attached to the ServiceBroker  1041  creates a Zone that corresponds to a part of the document. Also, an EditletService  1202  is attached to the ServiceBroker  1041 . The EditletService  1202  creates a Canvas that corresponds to the Nodes included in the Zone. 
     Examples of the ZoneFactories include an XHTMLZoneFactory  1211  and an SVGZoneFactory  1212 , which create an XHTMLZone and an SVGZone, respectively. As described above with reference to an example of the document, the text components of the document may be represented by creating an XHTMLZone. On the other hand, the image data may be represented using an SVGZone. Examples of the EditletService include an XHTMLEditlet  1221  and an SVGEditlet  1222 . 
       FIG. 22(   b ) shows the vocabulary connection in more detail. The vocabulary connection is an important feature of the document processing system, which allows a document to be represented and displayed in two different manners while maintaining the integrity of the document. The VCManager  302  that holds the ConnectorFactory  303  is a part of the vocabulary connection sub-system. The ConnectorFactory  303  creates the Connector  304  for the document. As described above, the Connector monitors the Node included in the source DOM, and modifies the Node included in the destination DOM so as to maintain the integrity of the connection between the two representations. 
     A Template  317  represents several Node conversion rules. The vocabulary connection descriptor (VCD) file is a template list which represents several rules for converting a particular path, an element, or a set of elements that satisfies a predetermined rule into another element. All the Templates  317  and CommandTemplates  318  are attached to the VCManager  302 . The VCManager is an object for managing all the sections included in the VCD file. A VCManager object is created for each VCD file. 
       FIG. 22(   c ) provides further detailed description with respect to the Connector. The ConnectorFactory  303  creates a Connector based upon the source document. The ConnectorFactory  303  is attached to the Vocabulary, the Template, and the ElementTemplate, thereby creating a VocabularyConnector, a TemplateConnector, and an ElementConnector, respectively. 
     The VCManager  302  holds the ConnectorFactory  303 . In order to create a Vocabulary, the corresponding VCD file is read out. As described above, the ConnectorFactory  303  is created. The ConnectorFactory  303  corresponds to the ZoneFactory for creating a Zone, and the Editlet for creating a Canvas. 
     Subsequently, the EditletService for the target vocabulary creates a VCCanvas. The VCCanvas also creates the Connector for the ApexNode included in the source DOM tree or the Zone. As necessary, a Connector is created recursively for each child. The ConnectorTree is created using a set of the templates stored in the VCD file. 
     The template is a set of rules for converting elements of a markup language to other elements. For example, each template is matched to a source DOM tree or a Zone. In a case of a suitable match, an apex Connector is created. For example, a template “A/*/D” matches all the branches starting from the Node A and ending with the Node D. In the same way, a template “//B” matches all the “B” Nodes from the root. 
     N. Example of VCD File with Respect to ConnectorTree 
     Further description will be made regarding an example of the processing with respect to a predetermined document. In this example, a document entitled “MySampleXML” is loaded in the document processing system.  FIG. 23  shows an example of the VCD script for the “MySampleXML” file, which uses the VCManager and the ConnectorFactoryTree. In this example, the script file includes a vocabulary section, a template section, and a component that corresponds to the VCManager. With regard to the tag “vcd:vocabulary”, the attribute “match” is set to “sample:root”, the attribute “label” is set to “MySampleXML”, and the attribute “call-template” is set to “sample template”. 
     In this example, with regard to the VCManager for the document “MySampleXML”, the Vocabulary includes the apex element “sample:root”. The corresponding UI label is “MySampleXML”. In the template section, the tag is “vcd:template”, and the name is set to “sample:template”. 
     O. Detailed Description of a Example of a Method for Loading a File to the System 
       FIGS. 24 through 28  provide a detailed description regarding loading the document “MySampleXML” in the system. In Step  1  shown in  FIG. 24(   a ), the document is loaded from a storage  1405 . The DOMService creates a DOM tree and a DocumentContainer  1401  that corresponds to the DocumentManager  1406 . The DocumentContainer  1401  is attached to the DocumentManager  1406 . The document includes an XHTML sub-tree and a MySampleXML sub-tree. With such a document, the ApexNode  1403  in the XHTML sub-tree is the top Node of the XHTML sub-tree, to which the tag “xhtml:html” is assigned. On the other hand, the ApexNode  1404  in the “MySampleXML” sub-tree is the top Node of the “MySampleXML” sub-tree, to which the tag “sample:root” is assigned. 
     In Step S 2  shown in  FIG. 24(   b ), the RootPane creates an XHTMLZone, Facets, and a Canvas. Specifically, a Pane  1407 , an XHTMLZone  1408 , an XHTMLCanvas  1409 , and a BoxTree  1410  are created corresponding to the ApexNode  1403 . 
     In Step S 3  shown in  FIG. 24(   c ), the tag “sample:root” that is not understood under the XHTMLZone sub-tree is detected, and a SubPane is created in the XHTMLCanvas region. 
     In Step  4  shown in  FIG. 25 , the SubPane can handle the “sample:root”, thereby providing a ZoneFactory having a function of creating an appropriate zone. The ZoneFactory is included in the vocabulary, and the vocabulary can execute the ZoneFactory. The vocabulary includes the content of the VocabularySection specified in “MySampleXML”. 
     In Step  5  shown in  FIG. 26 , the Vocabulary that corresponds to “MySampleXML” creates a DefaultZone  1601 . In order to create a corresponding Editlet for creating a corresponding Canvas, a SubPane  1501  is provided. The Editlet creates a VCCanvas. The VCCanvas calls the TemplateSection including a ConnectorFactoryTree. The ConnectorFactoryTree creates all the connectors that form the ConnectorTree. 
     In Step S 6  shown in  FIG. 27 , each Connector creates a corresponding destination DOM object. Some of the connectors include XPath information. Here, the XPath information includes one or more XPath representations used for determining a partial set of the source DOM tree which is to be monitored for changes and modifications. 
     In Step S 7  shown in  FIG. 28 , the vocabulary creates a DestinationPane for the destination DOM tree based upon the pane for the source DOM. Specifically, the DestinationPane is created based upon the SourcePane. The ApexNode of the destination tree is attached to the DestinationPane and the corresponding Zone. The DestinationPane creates a DestinationCanvas. Furthermore, the DestinationPane is provided with a data structure for rendering the document in a destination format and an Editlet for the DestinationPane itself. 
       FIG. 29(   a ) shows a flow in a case in which an event has occurred at a Node in the destination tree that has no corresponding source Node. In this case, the event acquired by the Canvas is transmitted to an ElementTemplateConnector via the destination tree. The ElementTemplateConnector has no corresponding source Node, and accordingly, the event thus transmitted does not involve an edit operation for the source Node. In a case that the event thus transmitted matches any of the commands described in the CommandTemplate, the ElementTemplateConnector executes the Action that corresponds to the command. On the other hand, in a case that there is no corresponding command, the ElementTemplateConnector ignores the event thus transmitted. 
       FIG. 29(   b ) shows a flow in a case in which an event has occurred at a Node in the destination tree that has been associated with a source Node via a TextOfConnector. The TextOfConnector acquires the text Node from the Node in the source DOM tree specified by the XPath, and maps the text Node to the corresponding Node in the destination DOM tree. The event acquired by the Canvas, such as a mouse event, a keyboard event, or the like, is transmitted to the TextOfConnector via the destination tree. The TextOfConnector maps the event thus transmitted to a corresponding edit command for the corresponding source Node, and the edit command thus mapped is loaded in the CommandQueue  1053 . The edit commands are provided in the form of an API call set for the DOM executed via the Facet. When the command loaded in the queue is executed, the source Node is edited. When the source Node is edited, a mutation event is issued, thereby notifying the TextOfConnector, which has been registered as a listener, of the modification of the source Node. Then, the TextOfConnector rebuilds the destination tree such that the destination Node is modified according to the modification of the source Node. In this stage, in a case that the template including the TextOfConnector includes a control statement such as “for each”, “for loop”, or the like, the ConnectorFactory reanalyzes the control statement. Furthermore, the TextOfConnector is rebuilt, following which the destination tree is rebuilt. 
     Embodiment 
     The data processing apparatus according to the exemplary embodiment includes the functions of the document processing apparatus  20  explained in the base technology as a part of it and easily creates the definition file which shows the correspondence relation between a source tree and a destination tree by the vocabulary connection explained in the base technology. Following the overview of the process of creating a definition file according to the exemplary embodiment in  FIG. 30 , a detailed description will be made mainly regarding the display mode by referring to  FIG. 31  and the subsequent figures. 
       FIG. 30  is a schematic diagram which illustrates the process of creating the definition file according to the exemplary embodiment. The data processing apparatus acquires an XML document file which is subject to be edited (hereinafter referred to as “source file”) and a schema file which defines the element structure of a source file. The schema file referred here is described in accordance with the specification, for example, XML-Schema and DTD (Document Type Definition). The definition file as a product is a file to create the destination file having the display layout information appropriate for editing the source file. The destination file can be said to be the filed destination tree, the destination tree which is described in the base technology. 
     In the presence of the schema file, the data processing apparatus creates a binding file from the schema file. The binding file is used for editing the display layout in the destination file. In the absence of the schema file, the data processing apparatus creates a binding file by extracting an element and its structure from the source file. In this case, the data processing apparatus extracts the element and its structure by extracting a child element from a root element of the source file by a tree traverse method. Furthermore, the rules on the element of the source file can be redefined by the binding file. For example, an element A in the source file supposedly has four child elements B when the binding file is created from the source file. In this case, the rules are listed in the binding file, stating that the number of the child elements B which the element A can have is up to four. A user can redefine the rules on the element A and the child element B via the method provided by the binding file. For example, the number of the child element B which the element A can have may be defined from 1 to 10. Even when the binding file is created form the schema file, the rules on such elements may be redefined within the rules defined in the schema file. As stated above, the binding file provides the rules on the elements and the function to define the rules. A description will be given in the following under the condition where the schema information which shows the element structure of the source file is acquired from the schema file. 
     A user can edit the binding file using the data processing apparatus. The user can set in the binding file the basic display layout of the destination file by GUI (Graphical User Interface). With this, a layout file is created by applying the display layout information defined in the binding file to each element of the schema information. The layout file is a HTML file which shows a specific display layout of each element included in the schema file. The layout file is not limited to a structured document file, a type of file which is structured by tags; however the layout file should be a file which includes the display layout information such as a spreadsheet application and an application for the presentation. The user can edit the display layout further elaborately by editing the layout file itself. In this exemplary embodiment, the basic setting of the display layout of the destination file is performed using the binding file; and the advanced setting of the display layout is performed using the layout file. 
     An XSLT file to set the data interchange format between the source file and the destination file is created in accordance with the correspondence relation between the element shown in the binding file and the display area of the layout file. Finally, a definition file is created showing the correspondence relation between the source file corresponding to the binding file and the destination file corresponding to the layout file based on the XSLT file. A description will now be given of a flow of these processes, focusing on the user interface. 
       FIG. 31  is a diagram which shows the schema file according to the exemplary embodiment. The schema file shown in the figure describes the rules on the element structure to which the source file shown in the following  FIG. 32  needs to follow. Also, this schema file is described in accordance with the feature called XML-Schema. For example, in  FIG. 31 , the data type of the element, which is in the third row from the top, named “customerList” is defined as “customerListType”. In the following row, the data type “customerListType” is defined to have four child elements, “listID”, “totalEstimate”, “totalNumber”, and “customer” in the respective namespaces “sfa”. Furthermore, the data type of “customer” is “customerType” and its contents are also defined. Also, the number of the element “customer” is defined to be at least 0. The source file must be described in accordance with the rules shown in the schema file. Since the schema file is a file which rules the data type and the structure of the each element included in the source file, the rules on the structure among the elements are more comprehensible than the source file itself. 
       FIG. 32  is a diagram which shows the source file corresponding to the schema file in  FIG. 31 . In this source file, the elements “listID”, “totalNumber”, “totalEstimate”, and “customer” are defined as child elements of the “customerList”. Also, these elements contain values. Three “customer” elements are contained. 
       FIG. 33  is a diagram which shows the definition file created based on the schema file in  FIG. 31  and the source file in  FIG. 32 .  FIG. 33  shows a part of the definition file. In the definition file shown in the figure, the rules are described for conversion of each element of the source file (e.g., “sfa:customerList/sfa:listID” and “sfa:customerList/sfa:totalNumber”) into the destination file in XHTML format. The data processing apparatus according to the exemplary embodiment can easily create the definition file in an intuitive user interface. 
       FIG. 34  is a diagram which shows an editing screen for a binding file. The data processing apparatus displays the binding file created from the schema file as an image in the predetermined format shown in  FIG. 34 . In the bottom area of the  FIG. 34  (hereinafter referred to as “property area”), each element shown in the schema file is displayed in tree view and, for example, its data type, is also displayed in editable format. In the property area, the child elements can be displayed in expanded view by checking a check box next to the element name. According to this aspect, even if vast numbers of elements are defined in the schema file, only the elements subject to be edited can be displayed. 
     The data processing apparatus sets a unique ID to each element. For example, the ID “L1” is set to the element “listID”. The ID is determined by combining the initial letter of the element “L” and the serial number “1”. Also, the data processing apparatus sets a unique sample value to each element. A sample value “2005-G30182” is set to the element “listID”. In the upper part of the center of  FIG. 34 , the area (hereinafter referred to as “layout area”) is set to define the display format of these elements. The user can reflect in the layout file by arranging the ID of each element in the layout area. The relation between the layout area and the layout file will be described by association in  FIG. 43  or after. In the middle row of the property area in  FIG. 33 , the display format is assigned so that the element “customer” is displayed in table format. This assignment is reflected in the layout file shown in the following  FIG. 35 . 
       FIG. 35  is a diagram which shows the editing screen for the layout file based on the editing result of the binding file in  FIG. 34 . The child element of the element “customer” is displayed in table format in accordance with the assignment in  FIG. 34 . For example, the element “customerList/customer/name” of the schema file corresponds to the most left display area of the table shown in the layout file. The setting in the layout area in  FIG. 34  is reflected in the display format. The user can edit the layout file in so-called WYSIWYG (What You See Is What You Get) in this edit display. 
     Thus, the display layout of each element shown in the schema file is saved as a layout file. The data processing apparatus creates the XSLT file in accordance with the correspondence relation between the element of such schema file and the element of the layout file, and, in addition, creates the definition file explained in the base technology. 
     The user can change the display position of the element by drag and drop in the editing screen of the layout file. If the editing is performed after the definition file is created, the data processing apparatus must reflect in the definition file the change in the correspondence relation between the element of the schema file and the display position of the layout file. The data processing apparatus monitors the correspondence relation between the sample value in the layout file and the element of the schema file. Therefore, even if the position of the element in the layout file is changed, the definition file can be updated in accordance with the position of the sample value. Each display element included in the layout file is identified by the sample value. Therefore, the correspondence relation is redefined, using the sample value in the layout file as a key when the XSLT file is created. 
       FIG. 36  is a screen view when the destination file based on the editing result in  FIG. 35  is displayed. The destination file is created from the source file in accordance with the definition file.  FIG. 36  is a screen displaying this destination file. Since there are three elements “customer” of the source file, three “customer” elements are displayed in accordance with the table format of  FIG. 35 . The user can edit the data of the source file via the screen in  FIG. 36 . This is the mechanism explained in the base technology as a vocabulary connection. 
       FIG. 37  is a diagram which shows another example of an editing screen for a binding file. As for the middle row of the property area in  FIG. 37 , the difference from  FIG. 34  lies in that the display format is assigned to display the element “customer” in list format. 
       FIG. 38  is a diagram which shows the editing screen for a layout file based on the editing result of the binding file in  FIG. 37 . The child element of the element “customer” is displayed in list format in accordance with the assignment of the display format in  FIG. 33 . Thus, the layout file is changed in accordance with the assignment of the display format in the binding file. In  FIG. 37 , the element “customerList/customer/name” of the schema file corresponds to the first element of each list shown in the layout file. The data processing apparatus creates the definition file explained in the base technology in accordance with the correspondence relation between such element of the schema file and the element of the layout file. 
       FIG. 39  is a screen view when the destination file based on the editing result in  FIG. 38  is displayed. Since there are three elements “customer” of the source file, the contents of the three “customer” elements are displayed in list in accordance with the list format of  FIG. 37 . The user can edit the source file via the screen in  FIG. 39 . 
       FIG. 40  is a diagram which further shows another example of an editing screen for a binding file. In  FIG. 40 , “count(N1)” is set by the editing manipulation by the user as the calculation formula to calculate the value of the element “totalNumber”. Since “N1” is the ID of the element “name”, the value of the element “totalNumber” is the number of the element “name” in the source file. Also, “sum(E1)” is set as the calculation formula to calculate the value of the element “totalEstimate”. Since “E1” is the ID of the element “estimate”, the value of the element “totalEstimate” is the total value of the value of the element “estimate” in the source file. Thus, each element can be handled in simple input format in the editing screen of the binding file, using not long element names, but the ID value. 
       FIG. 41  is a diagram which shows the editing screen for a layout file based on the editing result of the binding file in  FIG. 40 . There is no difference in  FIG. 41  and  FIG. 35 . 
       FIG. 42  is a screen view when the destination file based on the editing result in  FIG. 41  is displayed. In the item “totalNumber”, “3” (i.e., the number of the element “name” in the source file) is displayed. Similarly, in the item “totalEstimate”, “8000” (i.e., the total value (1000+3500+3500=8000) of the element “estimate” in the source file) is displayed. 
       FIG. 43  is a diagram which further shows another example of an editing screen for a binding file. A description will now be given, using another schema file different from the schema file shown in  FIG. 31  as an example. As shown in  FIG. 43 , the user can set the basic layout in the layout file by arranging the ID in the layout area. When the binding file is displayed, the ID of each element is arranged in the layout area by default. The arrangement in this case may be the arrangement in which the element structure in the schema file is reflected. For example, the elements in the parent-child or the sibling relation may be arranged so that the display position become close to one another. Also, when the element names are similar as in “totalNumber”, “Number”, and “subtotalNumber”, these elements may be arranged so that the display position become close to one another. As described above, compared to the cases that require the initialization of the arrangement of the ID and the creation of the arrangement from scratch, the laborsaving of the creation of the layout can be enhanced. 
       FIG. 44  is a diagram which shows the editing screen for the layout file based on the editing result of the binding file in  FIG. 43 . In the layout file, each element is displayed in accordance with the editing contents in the layout area in  FIG. 43 . 
       FIG. 45  is a screen view when the destination file based on the editing result in  FIG. 44  is displayed. 
       FIG. 46  is a schematic diagram which further illustrates a process of creating a definition file. Additionally in  FIG. 46 , the supplementary information is added to the binding file by the editing manipulation on the binding file by the user. The supplementary information is, for example, the definition or the redefinition of the rules on the element. The definition file is created based on this binding file; however, the XSLT file may be created instead of the definition file. In addition, the object to achieve the data mapping between the source file and the destination file, for example, the object of Java (registered trademark), may be created. 
     The description of the invention given above is based upon one illustrative embodiment. The embodiment is intended to be illustrative only and it will be obvious to those skilled in the art that various modifications to constituting elements and processes could be developed and that such modifications are also within the scope of the present invention. 
     INDUSTRIAL APPLICABILITY 
     The present invention improves the ease-of-use for the user in processing the data structured in a markup language.