Patent Publication Number: US-7908296-B2

Title: Integrating object-oriented design software with record-based CAD software

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present invention is a U.S. National Stage Application corresponding to PCT Application No. PCT/CA2007/000241, filed on Feb. 16, 2007, entitled “Integrating Object-Oriented Design Software With Record-Based Cad Software,” which claims the benefit of priority to U.S. Provisional Patent Application No. 60/774,096 filed on Feb. 16, 2006, entitled “Integrating object-oriented design software with record-based CAD software.” The entire content of the above-mentioned patent applications is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     This invention relates to systems, methods, and computer program products for modeling and design. 
     2. Background and Relevant Art 
     As computerized systems have increased in popularity, so has the range of applications that incorporate computational technology. Computational technology now extends across a broad range of applications, including a wide range of productivity and entertainment software. Indeed, computational technology and related software can now be found in a wide range of generic applications that are suited for many environments, as well as fairly industry-specific software. 
     Some examples of industry-specific application programs include those known as Computer-aided design (i.e., “CAD”) programs, such as AUTOCAD. In general, CAD programs provide a user with the ability to draw lines on a CAD user interface, where those lines represent various “design entities” or elements in a plan view of a raw design space. To manage each of the various design entities created through the user interface, CAD programs typically incorporate a record-based database. 
     In general, the record-based database can also be referred to as a “linear” database, since it includes a set of sequential records whose relationships are based primarily on the sequence/moment in time at which those records were created. For example, when a user creates a line (i.e., a “design entity”) in a CAD user interface, the data related to that line (such as type, position, etc.) are stored in a newly-created record in the record-based (linear) database. When a user creates the next line (or circle, etc.) in the CAD user interface, the corresponding linear (or sequential) database creates a new record in the linear database. Since the main relationship between these records is primarily based on sequence, each record includes little or no relation to other records within the database that were created much earlier or later in the sequence. 
     By contrast, there are also now design applications that incorporate non-sequential, three-dimensional (“3D”) relationships for records, such as object-oriented software programs used for design functions. Generally, an object-oriented database represents each entity as an intelligent object block (analogous to a linear database&#39;s record). In contrast with the record in a record-based database, which is basically just a collection of data, each object block can be thought of as an independent program of computer-executable instructions in addition to certain user-entered data. The independent, intelligent nature of object blocks can enable a wide range of functionality not otherwise available to records. 
     For example, object blocks can identify multiple relationships with other object blocks, regardless of sequence entered. In particular, an object-oriented design program incorporates a hierarchical database rather than a linear one. In addition, object blocks can determine how they relate to other object blocks and to the complete solution represented by a particular design. For example, if a line is requested to be a specific length (or shape) by text entry or any other manner, but the current design cannot allow it, the object block for the line understands that it cannot comply with the request due to its relations within the complete solution. The object block can nevertheless remember this request, and apply it at such time that other factors change to a point where the original request could be allowed. As a result, the object blocks of an object-oriented design program are dynamic, and the knowledge that can be maintained within an object block is substantially greater than any conventional linear record. 
     A properly structured object-oriented database, such as a design software program (e.g., a JAVA-based program), can be configured to convert the linear data from the record-based database to an appropriate format in an object-oriented database. In cases such as these, record-based design entities (such as a simple AUTOCAD line) can be modified or converted to implement detailed, object-oriented blocks. Unfortunately, organizations are sometimes hesitant to change to a new relational, object-oriented model, such as described above for any number of reasons. 
     For example, an organization may be reticent to remove or supplant existing legacy systems or related platforms using a record-based, linear database program. On one level, this may be due to the inherent difficulties with retraining employees who are already fluent in the use of linear database applications. In addition, the organizations may desire to avoid difficulties that could occur updating business partners who may need documentation in a new format (based on linear records). One will appreciate, therefore, that these and other such factors can create an inertia effect toward an organization&#39;s migration to a more effective, object-oriented database format. 
     BRIEF SUMMARY OF THE INVENTION 
     Implementations of the present invention provide systems, methods, and computer program products configured to integrate linear and object-oriented design programs in a seamless fashion. In particular, implementations of the present invention allow a user to work within a linear design application environment and, at the same time, incorporate some or all of the advantages of an object-oriented database. In one implementation, for example, a user can link one or more design entities from a linear design application to one or more object blocks of an object-oriented database. When the user modifies the geometry of the linked design entity (e.g., trimming a design entity line), the corresponding object block can recognize the modification to the design entity, and cause redefining of the data model in both the object-oriented database and record-based (linear) database as appropriate. 
     For example, a method of providing object-oriented entity manipulations through a user interface of the CAD application program can involve providing one or more object status item(s) in a CAD user interface. In such a case, the selection of the object status item(s) results in a change in object state for one or more design entities. The method can also involve receiving one or more selections to create or manipulate one or more design entities in the CAD user interface. In addition, the method can involve identifying an object state for each of the one or more design entity selections. Furthermore, the method can involve manipulating one or more database entries in accordance with the identified object state for each of the one or more design entities. 
     In addition, a system configured to provide a record-based application program with functionality of an object-oriented design application program can include one or more record-based application programs having one or more CAD user interfaces for receiving user input and providing display of the user input. The system can also include a linear database configured to store one or more linear records corresponding to one or more design entities created through the one or more CAD user interfaces. 
     In addition, the system can include an object-oriented design application program having one or more interface components configured to interact with the one or more record-based application programs. Furthermore, the system can include an object-oriented database configured to store one or more object blocks corresponding to any of the one or more design entities. In this case, the one or more interface components are configured to correlate changes in the one or more linear records with the one or more object blocks. The one or more interface components are also configured to correlate changes in the one or more object blocks with the one or more linear records. 
     Additional features and advantages of exemplary implementations of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such exemplary implementations. The features and advantages of such implementations may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims, or may be learned by the practice of such exemplary implementations as set forth hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1A  illustrates an implementation of the present invention in which a user creates or modifies one or more design entities through a CAD user interface that is linked to both a record-based database and an object-oriented database using a default setting; 
         FIG. 1B  illustrates an implementation of the present invention in which a user creates or modifies one or more design entities through the CAD user interface of  FIG. 1A  after selecting one or more object status items; 
         FIG. 1C  illustrates an implementation of the present invention in which an object block of the object-oriented database of  FIGS. 1A-1B  corrects a user selection for an impractical modification of a design entity in the CAD user interface of  FIGS. 1A-1B ; 
         FIG. 1D  illustrates an implementation of the present invention in which a user opens a three-dimensional interface and makes corresponding changes to one or more design entities of the CAD user interface in the three-dimensional interface; and 
         FIG. 2  illustrates a flowchart of a series of acts in a method of integrating an object-oriented database with a record-based, or linear, database in accordance with an implementation of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention extends to systems, methods, and computer program products configured to integrate linear and object-oriented design programs in a seamless fashion. In particular, implementations of the present invention allow a user to work within a linear design application environment and, at the same time, incorporate some or all of the advantages of an object-oriented database. In one implementation, for example, a user can link one or more design entities from a linear design application to one or more object blocks of an object-oriented database. When the user modifies the geometry of the linked design entity (e.g., trimming a design entity line), the corresponding object block can recognize the modification to the design entity, and cause redefining of the data model in both the object-oriented database and record-based (linear) database as appropriate systems, methods, and computer program products configured to integrate linear and object-oriented design programs in a seamless fashion. In particular, implementations of the present invention allow a user to work within a linear design application environment and, at the same time, incorporate some or all of the advantages of an object-oriented database. In one implementation, for example, a user can link one or more design entities from a linear design application to one or more object blocks of an object-oriented database. When the user modifies the geometry of the linked design entity (e.g., trimming a design entity line), the corresponding object block can recognize the modification to the design entity, and cause redefining of the data model in both the object-oriented database and record-based (linear) database as appropriate. 
     As will be understood more fully herein, these and other advantages are realized at least in part since implementations of the present invention provide one or more mechanisms for translating or linking record-based data (e.g., linear or sequential database entries representing graphical entities in a CAD application) to detailed, object-oriented blocks. This translation/linking can be accomplished and mediated at least in part through the use of one or more intermediate interface  107  components configured to correlate record-based changes with object blocks in an object-oriented database. Linking to the object blocks, in turn, allows a CAD interface to take advantage of some of the more complex features of an object-oriented system, such as producing, viewing and modifying three-dimensional (3D) views of a design. In one implementation, the object-oriented design application program is implemented using a JAVA-based programming language. 
     The used of object blocks (e.g., JAVA-based object blocks) through a separate or intermediate interface  107  allows a user to work within a record-based CAD application, within an object-oriented application, or within a third application linked to the CAD application by the object-oriented application. The user can then implement the functions and output from any or all of the CAD-based or objected-oriented-based applications in an integrated, seamless fashion, such as modifying (e.g., trimming, extending, or mirroring, etc.) design entities without additional reactors, lisp type programs, or additional input and without having to replace the pre-existing CAD-based application program. 
       FIG. 1A  illustrates an overview schematic diagram in which a CAD user interface is linked to both a record-based database and an object-oriented database via one or more intermediate interface  107  components using a default setting. In particular,  FIG. 1A  illustrates a basic CAD user interface  105  comprising a series of drawing tools  110 .  FIG. 1A  also illustrates, however, in contrast with typical CAD-based application programs, one or more object status items  115  provided by an object-oriented design application program. Furthermore,  FIG. 1A  illustrates the use of one or more intermediate interface  107  components  107 , which are part of the object-oriented design application program, that interface between the CAD user interface  105  and both a record-based database  113  and an object-oriented database  117 . 
     As a preliminary matter, reference herein to “CAD” or “AUTOCAD” is meant to describe programs that incorporate general design functionality using linear or record-based databases, rather than a specific reference to any particular existing product. In addition, although any database entry might be thought of as a “record” on some level, the term “record-based” when referring herein to an application program or database will refer to application programs or databases that primarily use sequential or “linear” database entry/modification mechanisms, rather than object-oriented database entries. As previously mentioned, these types of database entries (i.e., records) are not only typically sequential, but also tend to include only basic information about a design entity, such as design entity type, design entity position, or the like. In contrast to object-oriented applications that use object blocks, therefore, a “record” can be understood herein as a passive data entry, while an “object block” can be understood herein as an active data entry with added intelligence. 
     In any event,  FIG. 1A  illustrates an implementation of the present invention in which a user creates one or more design entities without selecting one or more object status items  115 . In this case, the object state for each design entity would be set to “off.” In general, object status item  115  can comprise any of a selectable button, icon, or other form of selectable option that would be presented through a graphical user interface on a computer display. In one implementation, the object-oriented design application provides one or more plugins or modules, in addition to the object status item  115 , which tag each design entity created or used in CAD user interface  115  with an object status field (not shown). The object status field for each design entity, therefore, presents the “object state,” which indicates whether the user has selected the object status item  115  for that design entity. 
     In this example,  FIG. 1A  shows that a user selects use of a line, and draws line  120 , potentially representing a wall in a design space. Since the user has not, in this example, selected item  115 , intermediate interface  107  determines that the object state for design entities  120  and  125  are set to “off,” (or other appropriate identifier in the object status field), and thus no desire from the user to link these design entities to an object block. As shown in  FIG. 1A , therefore, intermediate interface  107  identifies the object state from any object status field associated with instructions regarding design entity  120  as set to “off.” Intermediate interface  107  then simply passes instructions regarding the creation of design entity  120  as message  123  to record-based database  113 ; but sends no corresponding instructions to object-oriented database  117 . 
     In contrast with  FIG. 1A , however,  FIG. 1B  shows that the user has selected object status item  115  in the context of creating or modifying design entity  120 . In one implementation, mere selection of object status item  115  can involve intermediate interface  107  copying all record data (e.g.,  130 ,  135 ) corresponding to each design entity displayed in CAD user interface  105  (or all applicable records) and creating corresponding object blocks (e.g.,  133 ,  137 ) in database  117 . In the illustrated example, however, this selection simply causes a change in object state at least with respect to design entity  120  to “on,” so that design entity  120  is correlated with an object block. For example,  FIG. 1B  shows that the user&#39;s drawing of design entity  120  causes intermediate interface  107  to send a “create object” message  140  to object-oriented database  117 , in addition to passing message  123  (also shown in  FIG. 1A ) indicating a request to create a new record  130 . 
     In general, one will appreciate that there are a number of different ways that a user can correlate design entity  120  between record-based database  113  and object-oriented database  117 . For example, a user could select object status item  115  before drawing any design entities, and set that as a default for all design entities until deselecting the object status item  115 . Since each following design entity would have the same object state of “on,” the intermediate interface  107  would create or modify both a record and an object block corresponding to the design entity during creation, modification, or other form of update. 
     In other cases, however, the user could select on particular design entities to have a particular object state of “on” or “off.” In particular, the user could select object status item  115  during or after drawing line design entity  120 , and/or make an additional selection (not shown) indicating that design entity  120  should have an object state of “on.” In such a case, intermediate interface  107  could recognize creation or modification of design entity involves modifications to an object block in database  117  as well as a record in database  113 , while creation or modification of design entity  125  involves modifications only to a record in database  113 . In still further cases, one or more selection items (not shown) can be provided for the user to select conversion of all design entity records (or all records, design entity or not) from database  113  to database  117 . This would involve any one or more of copying, transferring, or moving data from database  113  to database  117  to ensure proper correlation, or total substitution of record-based database  113  with object-oriented database  117 . 
     In addition to the foregoing,  FIG. 1B  also shows that selection of object status item  115  can result in the presentation of additional user interfaces or design choices to a user. For example,  FIG. 1B  shows that upon identifying that the user has selected object status item  115 , intermediate interface  107  presents design interface options  145  as an inclusion in CAD user interface  105 , or as a separate standalone interface. In either case, the user can add refinements or other details to a design entity in CAD user interface  105 . For example,  FIG. 1B  shows that the user has selected a “wall” option, in addition to the object status item  115 . Thus, when the user draws design entity  120 , the intermediate interface  107  recognizes the object state for the design entity, as well as the corresponding details entered through interface  145 . 
     The intermediate interface  107  then sends message  140  to object-oriented database  117  not only to create an object ( 133 ) for design entity  120 , but also to include the additional details requested, such as that the design entity represents a wall, or even other details about the wall structure, color, design, texture, materials, etc. Ordinarily, however, these and other details might not be included in the typical record for a design entity in a CAD application. For example,  FIG. 1A  shows that intermediate interface  107  simply sends the same message  123  as shown in  FIG. 1A  that the type of design entity is a “line,” as well as the position information. In any event, one will appreciate that design entities that are correlated with object blocks can be opened and modified in any user interface (whether the CAD user interface  105 , or another user interface provided by the object-oriented design application program). By contrast, design entities that are not correlated with object blocks (i.e., object status set to “off”) will generally be opened or modified only in the CAD application program. 
       FIG. 1C  illustrates an implementation of the present invention in which an object block of the object-oriented database of  FIGS. 1A-1B  attempts to resolve a potentially impractical user selection. In particular,  FIG. 1C  illustrates at least one of the advantages provided to the record-based CAD application by implementing the functionality of an object-oriented design application/database. For example,  FIG. 1C  shows that the user extends the design entity  125 , in this case a wall, through design entity  120 , which in this case is also an outer wall. 
     In a typical CAD based application, the user might be free to draft this extension to design entity  125  because the records  130 ,  135  of database  113  do not resolve the conflict, and only implement or record the user&#39;s drawing selection. By contrast,  FIG. 1C  shows that the objects  133 ,  137  of object-oriented database  117  can utilize intelligence to resolve the conflict. For example,  FIG. 1C  shows that, upon receiving the user&#39;s selection, intermediate interface  107  sends message  127   a  to record-based database  113 , of the user&#39;s selection for line  125 . In addition, intermediate interface  107  sends message  127   b  to object-oriented database  117 , which also includes essentially the same information, as applicable, regarding the user&#39;s selection for line  125 . In contrast with records  120  and  125 , however,  FIG. 1C  shows that object  137  determines based on its own data (as well as, potentially, on a comparison with the data of object  133 ) that this request is either impractical or impermissible. 
     Accordingly,  FIG. 1C  shows that object  137  sends a response message  143  to intermediate interface  107  indicating that this request is not permissible. Intermediate interface  107  can then perform any number of corresponding response actions. In one implementation, for example, intermediate interface  107  passes one or more messages (not shown) to CAD user interface  105 , which causes the new but impermissible user selection (shown in dashes) to be removed or corrected. For any such removal or correction, intermediate interface  107  can also pass one or more additional messages (not shown) to record-based database  113  to update record  135  in the same manner. In other or alternative implementations, intermediate interface  107  can send one or more messages to prompt the user for additional action based on a warning signal, and/or pass a corresponding signal to record  135  in database  113 . 
     One will appreciate that this corrective ability can be applied to a wide number of design entities drawn or made by a user in CAD user interface  105 . For example, the object blocks of database  117  could correct a situation where the user drew the components of a chair and placed those components inadvertently on top of a wall. In such a case, the object blocks might cause the CAD user interface  105  to automatically move the chair to a more appropriate position, if not deleting the user&#39;s placement altogether. 
     In addition to the foregoing, the object blocks of database  117  can be used to correct or implement user selections made in views other than the CAD user interface  105 . For example,  FIG. 1D  shows that the user has selected a “3D” option  116 . In general, 3D option  116  can be any of a button, icon, or menu pull-down option, or the like provided by the object-oriented design application (or plugin/component thereof) through the CAD user interface  105 .  FIG. 1D  shows that, upon such selection, 3-D interface  109  is opened, showing lines  120  and  125  as walls in three-dimensional format. 
     In general, the three-dimensional format of interface  109  is generated at least partly from the more detailed information contained in the object blocks (e.g.,  133 ,  137 ) of database  117 . For example, the object blocks of database  117  can contain information not only of size or position, but also of texture, color, width or gauge, number or types of mounting components, as well as three-dimensional representations of the types of materials used in the wall (e.g., glass, wood, dry wall, etc.), the lighting at a particular angle, etc. The object blocks can also include information about pricing for various components, or other forms of information deemed applicable for each design entity. As such, the user can then navigate around or through any of these design entities, in various angles and degrees of proximity, and even select pricing or other details instantly with respect to a particular design entity. The user can also make any selections or changes to the three-dimensional views (or two-dimensional views, as appropriate) of each design entity, and have those reflected seamless in all entries for each corresponding record or object, regardless of database ( 113  and/or  117 ). 
     In this case, for example,  FIG. 1D  shows that the user&#39;s selection of 3-D item  116  results not only in the opening of 3-D interface  109 , as well as the opening of a color palette interface  147 . In this example,  FIG. 1D  further shows that the user selects one of the colors from color palette interface  147 , which the intermediate component  107  then applies to design entity  127 . Intermediate component  107  then sends message  150  to database  117 , which updates object  137  for this color selection (if available). Similarly, and if applicable, intermediate component  107  can then send a message  155  to record-based database  113  to update record  135  for design entity  125 . In the event color is not used in the CAD user interface  105 , intermediate component  107  may be able to even omit sending message  155  at all. 
     Accordingly,  FIGS. 1A-1D  illustrate a number of different components and schematics for seamlessly integrating the functionality of an object-oriented design application with a record-based design application. In addition to the foregoing, implementations of the present invention can also be described in terms of flowcharts of acts in a method of accomplishing a particular result. For example,  FIG. 2  illustrates a sequence of acts in a method of providing object-oriented entity manipulations through a user interface of the CAD application program. The acts of  FIG. 2  are described below with respect to the schematics and components of  FIGS. 1A-1D . 
     For example,  FIG. 2  shows that a method in accordance with an implementation of the present invention can comprise an act  200  of providing one or more object status items in a CAD user interface. Act  200  includes providing one or more object status items in a CAD user interface, wherein selection thereof results in a change in object state for one or more design entities. For example,  FIG. 1A  illustrates object status item  115 , which, if not selected by the user, defaults to an object status of “off.” In such a case, the selected design entities are created only in conjunction with the creation of records in record-based database  113 . 
       FIG. 2  also shows that the method can comprise an act  210  of manipulating one or more design entities in the CAD user interface. Act  210  includes receiving one or more selections to create or manipulate one or more design entities in the CAD user interface. For example,  FIGS. 1A-1C  show that the user draws or modifies one or more design entities, such as design entity  120  in CAD user interface  105 . Similarly,  FIG. 1D  shows that the user can open a three-dimensional view from the CAD user interface  105 , and modify the design objects originally created in the three-dimensional view through 3-D user interface  109 . 
     In addition,  FIG. 2  shows that the method can comprise an act  220  of identifying an object state for each design entity. Act  220  includes identifying an object state for each of the one or more design entity selections. For example,  FIG. 1A  shows that object status item  115  has not been selected, and as such, intermediate interface  107  would identify the corresponding object state for any corresponding user selection or design choice to be set to “off” or some other default identifier. By contrast, such as with  FIGS. 1B-1D , the object status item  115  is selected. In those examples, therefore, the intermediate interface  107  will identify the object state user selections or modifications of a design entity made while this item is selected to be set to “on.” 
     Furthermore,  FIG. 2  shows that the method can comprise an act  230  of manipulating a database entry based on the object state. Act  230  includes manipulating one or more database entries in accordance with the identified object state for each of the one or more design entities. For example,  FIG. 1A  shows that, since the object state for design entity  120  is set to the default or “off” value, intermediate interface  107  scans the object state for the given user design entity selections, and identifies that the design entity is not to be associated with an object block As such, intermediate interface  107  simply passes on any instructions from the interface to record-based database  113 . 
     By contrast, such as in  FIGS. 1A-1D , where the object state for a user selection is set to “on,” or some other value indicative of using the object-oriented design application, intermediate interface  107  scans the object state for each design entity selection and identifies that there is to be an associated with an object block. As such, intermediate object manipulates object blocks (e.g.,  133 ,  137 ) in addition to passing manipulation instructions to database  113 . One will appreciate, therefore, that in at least one implementation, an important feature includes the intermediate interface  107  scanning all user selection instructions from CAD user interface  105  for object state (e.g., via an object status field) prior to manipulating either or both of the record-based or object-based databases  113 ,  117 . 
     Accordingly,  FIGS. 1A-2  provide a number of different components, schematics, and mechanisms for implementing the functionality of an object-oriented design application program through a traditional record-based design application program, such as a CAD-based application program. In particular, implementations of the present invention provide object-oriented design software that allows conversion of record-based data to object-oriented data in representation of graphical entities in a record-based CAD application. Implementations of the present invention also provide object-oriented design software that allows conversion of simple record-based entities of CAD software to detailed object-oriented blocks. In addition, implementations of the present invention provide object-oriented design software that allows the user to work in a record-based CAD application, utilizing the commands, functions and output of the CAD application, while benefiting from the advantages of the object-oriented database of the object-oriented design software. 
     Furthermore, implementations of the present invention provide object-oriented design software that allows the user to work within a record-based CAD application, within the CAD design software interface, or within a third application linked to the CAD application by the design software application, allowing the use of functions and output from all or any of the applications. Still further, implementations of the present invention provide object-oriented design software whereby record-based entities of a CAD application can be used to modify (such as trimming, extending or mirroring etc.) object-oriented entities without additional reactors, lisp type programs or additional input. 
     The embodiments of the present invention may comprise a special purpose or general-purpose computer including various computer hardware, as discussed in greater detail below. In particular, embodiments within the scope of the present invention also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer. 
     When information is transferred or provided over a network or another communications connection (either hard-wired, wireless, or a combination of hardwired or wireless) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of computer-readable media. 
     Computer-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. 
     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.