Abstract:
A process is set forth for previewing a table attachment on a mobile communication device, and upon identifying table content of interest viewing and/or retrieving the entire table from an attachment server. In one embodiment, a small 4×4 row/column preview is presented on the device of every table found in a document attachment, with the cell content textual information limited to the requesting device display capabilities. This limitation avoids any requirement to download large amounts of individual cell content to the device. Thus, the user is able to quickly identify which tables are of interest and then request a full table download from the attachment server in an on-demand fashion. In this regard, the preview table itself preferably also functions as a link to the full table stored at the server to facilitate easy retrieval to the device for viewing in a spreadsheet view.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The instant application is a continuation of U.S. patent application Ser. No. 11/093,853, filed Mar. 30, 2005, titled “Method for Requesting and Viewing a Preview of a Table Attachment on a Mobile Communication Device,” the contents of which are incorporated herein. 
     
    
     FIELD 
       [0002]    The following is directed in general to displaying content on mobile communication devices, and more particularly to a method for previewing a table attachment on a mobile communication device. 
       BACKGROUND 
       [0003]    Mobile communication devices are becoming increasingly popular for business and personal use due to a relatively recent increase in number of services and features that the devices and mobile infrastructures support. Handheld mobile communication devices, sometimes referred to as mobile stations, are essentially portable computers having wireless capability, and come in various forms. These include Personal Digital Assistants (PDAs), cellular phones and smart phones. While their reduced size is an advantage to portability, limitations in download bandwidth and device screen size give rise to challenges in viewing large documents with multiple embedded tables, having a large number of columns and rows for presenting information in a tabular format. 
         [0004]    For wireless devices that support viewing of attachments, this represents a large amount of information for downloading, requiring a large amount of bandwidth and the associated cost thereof. Additionally, the user must wait for an extended period of time while the device is downloading the complete table. 
         [0005]    Since mobile communication devices have limited screen real estate, it is known in the art to provide an Attachment Server (AS) for delivering “on-demand” content to wireless device users in order to minimize bandwidth, and device CPU/memory usage. When the user of a wireless device views a document attachment that uses tables, the Attachment Server typically downloads the document text to the Attachment Viewer (AV) on the mobile device along with a selectable link (e.g. [Table: N]), rather than the entire table contents. The user can then retrieve the entire table, if desired, by selecting the link. By downloading only the text and a link to the table, and providing the user with an option for retrieving or viewing the entire table attachment, such existing architectures thereby adhere to the on-demand design principle set forth above. 
         [0006]    Unfortunately, the selectable link (e.g. [Table: N]) provides no information relating to the actual content of the table. Some documents use tables extensively to present information. Indeed, in some cases the entire document is created using only tables containing the entire textual content. These types of table-centric documents, when viewed on the wireless device through the foregoing on-demand architecture, are represented only by a large number of selectable table links, without any other textual information. For these types of documents the user is unable to discern which of the table(s) contain information that is relevant to them and thus should be retrieved. The user is therefore required to retrieve some, if not all, of the tables in the document in order to identify any table(s) of interest. Consequently, the design principle of offering on-demand retrieval, wherever possible, is defeated by such multiple downloads of irrelevant attachment parts. 
       SUMMARY 
       [0007]    According to one aspect, a method is provided for previewing a table attachment on a mobile communication device, and upon identifying table content of interest viewing and/or retrieving the entire table. 
         [0008]    In one embodiment, a small 4×4 row/column preview is presented on the device of every table found in a document attachment, with the cell content textual information limited to the requesting device display capabilities (e.g. typically 8-32 characters per cell). This limitation avoids any requirement to download large amounts of individual cell content to the device, which otherwise would defeat the on-demand architectural design principle. 
         [0009]    Thus, the embodiments set forth herein allow the user to quickly identify which table(s) is (are) of interest and then request full table download from the Attachment Server in an on-demand fashion. In this regard, the preview table itself preferably also functions as a link to the full table stored at the server to facilitate easy retrieval to the device for viewing in a spreadsheet view. 
         [0010]    Additional aspects and advantages will be apparent to a person of ordinary skill in the art, residing in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    A detailed description of the preferred embodiment is set forth in detail below, with reference to the following drawings, in which: 
           [0012]      FIG. 1  is a block diagram of a network environment in which the preferred embodiment may be practiced; 
           [0013]      FIG. 2  is a device screen display of a plurality of table attachments, according to the prior art; 
           [0014]      FIG. 3  is a device screen display showing preview of a plurality of table attachments as in  FIG. 2 , according to an embodiment; 
           [0015]      FIGS. 4A and 4B  are device screen displays showing menu command options for retrieving and viewing, respectively, the previewed table attachment of  FIG. 3 ; 
           [0016]      FIG. 5  is a device screen display showing the retrieved table of  FIGS. 4A and 4B ; 
           [0017]      FIG. 6  is a tree diagram showing the basic structure of a Document Object Model (DOM); 
           [0018]      FIG. 7  shows the top-level of the DOM structure in  FIG. 6 ; 
           [0019]      FIG. 8  shows an exemplary DOM structure for a word processing document; 
           [0020]      FIG. 9  shows an exemplary DOM structure for a table document; 
           [0021]      FIG. 10  shows an exemplary DOM structure for a word processing document containing an image subdocument; 
           [0022]      FIG. 11  is a flowchart showing a client-side process for previewing a table attachment using an attachment viewed on a mobile communication device; 
           [0023]      FIG. 12  is a DOM structure graph presentation of a sample document containing a referenced table component added to the DOM structure as an attribute of an external component reference (ECR) command; 
           [0024]      FIG. 13  is a flowchart showing a server-side process for constructing a table component as a preview for the referenced table component of  FIG. 12 , and adding the preview table component as an attribute to the ECR command for previewing a table attachment; 
           [0025]      FIG. 14  is a DOM structure graph presentation of the document in  FIG. 12  following the process of  FIG. 13 ; 
           [0026]      FIG. 15  is a flowchart showing a server-side process for persisting the ECR command and the attached preview table component with its formatting properties to construct the preview table; and 
           [0027]      FIG. 16  is an illustration of sample documents. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0028]    With reference to  FIG. 1 , network environment  10  is shown in which the preferred embodiment may be practiced. Network environment  10  includes at least one mobile communication device  12  communicating via a wireless network/Internet  14  to a server  28 , via a firewall security server  29 , for downloading document attachments to the devices  12 . While only one server  28  is shown for illustration purposes, a person of skill in the art will understand that network environment  10  could have many such servers for hosting web sites or graphic download sites, providing access to picture files such as JPEG, TIFF, BMP, PNG, SGI, MP4, MOV, GIF, SVG, etc. As would be understood by one of ordinary skill in the art, wireless networks  14  include GSM/GPRS, CDPD, TDMA, iDEN Mobitex, DataTAC networks, or future networks such as EDGE or UMTS, and broadband networks like Bluetooth and variants of 802.11. 
         [0029]    As discussed above, for documents that use embedded tables, or for documents that are constructed using only tables the existing “on-demand” architecture displays a series of embedded links to the tables, as shown in  FIG. 2 . This forces the user to retrieve each and every table in order to view the table content, which is a time/bandwidth consuming operation if the user only needs information from one or a few of the tables. 
         [0030]    The table preview feature set forth herein, presents the user with a small preview of the table content on a mobile device  12  in “Document View”, as show in  FIG. 3 . Specifically, the table preview feature displays the first 4 columns/rows of an embedded table in order to quickly give the user an idea of what the table content is. In order to view the full table, the “Table Link” header in the preview acts as a selectable link and “Retrieve” is available from the menu when clicking the track wheel of device  12 , as shown in  FIG. 4A . The full table can then be viewed in “Spreadsheet View” using the “View” command, as shown in  FIG. 4B . 
         [0031]    Finally, the full table in the document can be viewed in Spreadsheet View after it has been successfully been retrieved from the Attachment Service, as shown in  FIG. 5 . 
         [0032]    Before turning to the specifics of the client-side and server-side applications for the table preview feature, a description is provided herein of the structure of a Document Object Model (DOM) for a document attachment to be viewed on the mobile communication device  12 . 
         [0033]    The attachment server  28  uses a file-parsing distiller in the preferred embodiment, for a specific document type, to build an in-memory Document Object Model (DOM) structure representing an attachment of that document type. The document DOM structure is stored in a memory cache of server  28 , and can be iterated bi-directionally. 
         [0034]    As shown in  FIG. 6 , the graph-based document DOM structure consists of nodes and leaves. The nodes serve as the parents of leaves and nodes, while leaves are end points of a branch in the graph. Each node and leaf can have a set of attributes to specify its own characteristics. For example, a paragraph node can contain attributes to specify its alignment, style, entry of document TOC, etc. In addition, each of the nodes and the leaves has a unique identifier, called a DOM ID, to identify itself in the document DOM structure. 
         [0035]    The document DOM structure is divided into three parts: top-level, component and references. The top level refers to the document root structure, while the main document is constructed in the component and the references represent document references to either internal or external sub-document parts. The following paragraphs examine each part in detail. 
         [0036]    The root node of a document DOM structure, referred to as “Document”, contains several children nodes, referred to as “Contents”, which represent different aspects of the document contents. Each “Contents” node contains one or multiple “Container” nodes used to store various document global attributes. The children of the “Container” nodes are components, which store the document structural and navigational information. When the attachment server  28  builds the DOM structure for an attachment file for the first time, the top-level structure is a single parent-child chain as shown in  FIG. 7 : 
         [0037]    Three types of components are defined by the attachment server  28 : text components, table components and image components, which represent text, tables and images in a document, respectively. The text and table components are described in detail below, and the image component structure is identical. 
         [0038]    A component consists of a hierarchy of command nodes. Each command represents a physical entity, a property, or a reference defined in a document. For the text component, the physical entity commands are page, section, paragraph, text segments, comments, footnote and endnote commands, which by name define the corresponding entity contained in a document. The property commands for the text component are font, text color, text background color, hyperlink start/end and bookmark commands. The text component has only one reference command, referred to as the text reference command, which is used to reference a subdocument defined in the main body of a document. Usually, the children of a text component are page or section command nodes that, in turn, comprise a set of paragraph command nodes. The paragraph command can contain one or multiple nodes for the remaining command types. 
         [0039]    Using the following sample text document, the corresponding document DOM structure is shown in  FIG. 8 : 
         [0000]    
       
         
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 First paragraph. 
               
               
                   
                 Second paragraph with  bold  and red text. 
               
               
                   
                   
               
             
          
         
       
     
         [0040]    As  FIG. 8  demonstrates, the section command, which is the child of the text component, consists of two paragraph commands. The first paragraph command contains one text segment command and the text content for that paragraph is added as an attribute to the text segment command. The second paragraph command has a relatively more complex structure, as the text properties in the paragraph are much richer. Each time a text property (font, text color, etc) changes, a corresponding text property command is created and the change value is added to that command as an attribute. The subsequent text segment command records the text with the same text property as an attribute. As document structure gets richer and more complex, more commands of corresponding types are created and the document properties are added as attributes to those commands. 
         [0041]    The table component has the same three types of commands as the text component, but different command names. The document DOM structure for the sample table document below is shown in  FIG. 9 : 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Cell One 
                 Cell Two 
               
               
                   
                 Cell Three 
                 Cell Four 
               
               
                   
                   
               
             
          
         
       
     
         [0042]    As shown in the  FIG. 9 , the table component has physical entity type commands of table, tablerow and tablecell, where the tablecell command can contain all available commands for the text component. In the example above, the first child TableRow command of the table command has an attribute “Index” defined by value of 0. This indicates that the indicated table row is the first one defined in the table. The attribute of the leftmost table cell command in  FIG. 9  has the same meaning. A document sometimes contains subdocuments, for example images, tables, text boxes etc. The DOM structure set forth herein uses a reference command to point to the graph of such subdocuments. Thus, for the sample document depicted in  FIG. 16 , the attachment server  28  generates the DOM structure shown in  FIG. 10 . 
         [0043]    The structure shown in  FIG. 10  is identical to that discussed above in connection with  FIGS. 8 and 9 , except for the attributes of the two reference commands. The attachment server  28  constructs the image in “Sample Three” as a separate image component, which contains all of the image data in its own DOM hierarchy. In the DOM structure for the main document, the values of the “Ref” attributes of those two reference commands point to the image component, as indicated by the dashed lines, such that the DOM structure connects together all parts of the document. 
         [0044]    Returning now to the preferred embodiment, the client component (Attachment Viewer (AV) application on device  12 ), when requesting a document attachment conversion from the server component (Attachment Server (AS)  28 ), informs the server of its device and feature specific capabilities such as screen size, color capabilities and functionality support when requesting an operation. This allows the server  28  to tailor its response to the requesting device  12  and optimize bandwidth utilization and minimize device CPU/storage usage while preserving the device presentation capabilities (e.g. color presentation data will not be returned to a monochrome device and vice versa). 
         [0045]    For the table preview capability, the client (AV) will as part of the attachment conversion request inform the server  28  that it is capable of showing table previews as well as supplying the requesting device  12  screen resolution and color information. 
         [0046]    This information enables the server  28  to return UCS (Universal Content Stream) data back to the device  12  containing preview table information preferably for a 4×4 row/column table with individual cell content limited to between 8-32 characters based on the requesting device screen information as well as preview table color information if supported by the device. A DOM ID for the full table is also returned to the AV on device  12  that allows the user to request the full table for viewing in spreadsheet view, if desired. 
         [0047]    A flow chart of the device side request process is shown in  FIG. 11 . At step  110 , the user requests the full content of an attachment (e.g. an attachment to an email), by appropriate operation of the user interface for device  12 . In response, at step  115 , the device AV issues a document request to the AS server  28  for the first chunk (e.g. typically 3K) of the document attachment configured for the device display width, height and number of colors the device can display. 
         [0048]    If the download request is successful (a YES branch at step  120 ), the client-side AV determines whether a table preview is included in the first portion (e.g. 3K of downloaded data. If not (step  125 ), the device displays the normal text content (step  130 ). 
         [0049]    The AV then issues any further requests for additional chunks of the document attachment (a YES at step  135 ), and process flow returns to step  120 . Otherwise, if the entire document has been downloaded (a NO at step  135 ), then the process terminates (step  140 ). 
         [0050]    If a request to download a chunk of data from the AS on server  28  is unsuccessful (i.e. a NO at step  120 ), then an error flag is generated and an error message displayed (step  145 ), following which the process terminates (step  140 ). 
         [0051]    If, as step  125 , a table preview is included in the chunk of downloaded data the AV displays the table preview, as shown in  FIG. 3 , and associates the DOM ID for the full table (stored in server  28 ) in the table link (step  150 ). If additional content (beyond the table preview) is available in the data chunk for viewing (step  155 ), the additional content is displayed (step  130 ). Otherwise, process flow branches to step  135 . 
         [0052]    Turning now to the server-side process, when the attachment server  28  receives a document containing embedded tables, it first constructs the DOM structure for the document if it does not already exist in the in-memory DOM structure cache. Each embedded table in the file is constructed as an external table component and is added to the DOM structure as an attribute of an external component reference (ECR) command, as described in greater detail below. 
         [0053]    The corresponding DOM structure for the following sample document containing an embedded table, is shown in  FIG. 12  where, in order to simplify the graph, the DOM structure does not contain the detailed graph presentation for the embedded table: 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 
               
               
                   
               
               
                 Test 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Cell One 
                 Cell Two 
               
               
                   
                 Cell Three 
                 Cell Four 
               
               
                   
                   
               
             
          
         
       
     
         [0054]    As shown in  FIG. 12 , the table component is added as attribute “Ref” to the external component reference command (ECR), which is a node in the DOM graph structure for the main document. 
         [0055]    The server-side process of  FIG. 13  begins at step  135  to iterate through the entire document DOM structure  130 . Provided the un-iterated remaining portion of the DOM structure continues to contain commands (step  140 ), the next command is iterated (step  145 ). Otherwise, the process ends (step  150 ). If the process encounters an ECR command (step  155 ) and the component being referenced is a table (step  160 ), the process constructs a table component (step  165 ), which is a preview for the referenced table component. This preview table component is added as an attribute to the ECR command (step  170 ), as shown in  FIG. 14 . 
         [0056]    The preview table component contains only partial information about the referenced table. By default, as discussed above, the preview table preferably has only a maximum of 4 rows and 4 columns of the original table, and each table cell includes up to 16 characters. However, a person skilled in the art will understand that the numbers of table rows, columns and table cell characters are configurable and can be dynamically set in the conversion request. In addition the table formatting information is preserved in the preview table component. 
         [0057]    After the preview table component is constructed, it is added as an attribute to the original ECR command, as discussed above. During the response and resulting DOM graph construction for a conversion request, the attachment server  28  persists the ECR command and the attached preview table component with its formatting properties. The flow chart of  FIG. 15  sets forth the steps of persisting the ECR command and attached preview table component in the document DOM structure of  FIG. 14  with the required formatting properties. 
         [0058]    After initialization of variables ( 140 ), the server process iterates the referenced table component (step  145 ) extracted from the ECR command shown in  FIG. 14 . Provided that there are commands remaining to be iterated (step  150 ), a determination is made as to whether the next command is a Table Row command (step  160 ), Table Cell command (step  165 ), Text Segment command (step  170 ), or whether (step  175 ) the table cell character index (m_iCharindex) is less than the maximum number of character in each table cell (kiMaxCellChar). If the result of each of these determinations is NO, then process flow returns to step  150 . On the other hand, if there are no further commands then the process ends (step  155 ). 
         [0059]    If the next command is a Table Row command (step  160 ), a determination is made at step  180  as to whether the Table row index (m_iRowIndex) exceeds the maximum number of rows in the preview table (kiMaxRow). If no, then a table row command is created and the attributes from the original table row command are copied to the new table row command (step  185 ), the table row index (m_iRowIndex) is incremented (step  190 ), the table cell index (m_iCellIndex) and Table cell character index (m_iCharindex) are reset (step  195 ), and the new command is added to the preview table DOM structure hierarchy (step  200 ). 
         [0060]    If the next command is a Table Cell command (step  165 ), a determination is made at step  210  as to whether the table cell index (m_iCellIndex) exceeds the maximum number of cells in the preview table (kiMaxCell). If no, then a table cell command is created and the attributes from the original table cell command are copied to the new table cell command (step  215 ), the table cell index (m_iCellIndex) is incremented (step  220 ), the table cell character index (m_iCharindex) is reset (step  225 ), and the new command is added to the preview table DOM structure hierarchy (step  200 ). If at step  210  the table cell index (m_iCellIndex) does not exceed the maximum number of cells in the preview table (kiMaxCell), then process flow returns to step  150 . 
         [0061]    If the next command is a Text Segment command (step  170 ), a determination is made at step  230  as to whether the table cell character index (m_iCharindex) is less than the maximum number of characters in each cell (kiMaxCellChar). If yes, then a text segment command is created (step  235 ), then at step  140  the text from the original text segment command is copied, where the amount of text to be copied is the lesser of the number of characters in the original text segment and (kiMaxCellChar−m_iCharindex). At step  245 , the copied text is added to the new text segment command as an attribute, where m_iCellIndex. +=number of character copied. The new command is then added to the preview table DOM structure hierarchy (step  200 ). If at step  230  the table cell character index (m_iCharindex) is not less than the maximum number of characters in each cell (kiMaxCellChar), then process flow returns to step  150 . 
         [0062]    If at step  175  the table cell character index (m_iCharindex) is less than the maximum number of character in each table cell (kiMaxCellChar), then a command is created (step  250 ) that is of the same type as in the original document. The new command is then added to the preview table DOM structure hierarchy (step  200 ). 
         [0063]    In summary, since the preview table for a table component is cached in the DOM structure as an attribute of the corresponding ECR command, memory consumption is slightly increased. However the processing time is significantly reduced by eliminating extra iterations of the table component on repeated file conversion requests. 
         [0064]    A person skilled in the art, having read this description of the preferred embodiment, may conceive of variations and alternative embodiments. 
         [0065]    All such variations and alternative embodiments are believed to be within the ambit of the claims appended hereto.