Abstract:
A page design system addresses the need to impart flexibility into the design and customization of graphical user interfaces for applications. The graphical user interface includes pages and display groups within each page, and the page design system permits each individual page to be modified to suit the needs of a particular customer. So that the pages do not depart from their fundamental purpose to too great of an extent, the page design system guides and constrains the modifications to each page. In particular, the page design system constrains customization of each display group according to established definitions of admissible graphical user interface elements that are appropriate for each page, and each display group of elements within the page.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This disclosure relates to the design of graphical user interfaces. In particular, this application relates to a page designer that guides and constrains customization of user interface pages of an application in an appropriate manner. 
     2. Related Art 
     Explosive growth in digital processing technology has led to the ubiquitous presence of applications of every kind running on an immense spectrum of devices. Most applications include a graphical user interface through which an operator interacts with the application. For instance, an insurance claim processing application presents user interface screens that guide the operator through the claim submission, validation, and payment/rejection process. 
     It is the case, however, that not every customer of an application has exactly the same needs. In some instances it would be beneficial to customize the graphical user interface of an application to better suit the needs of a particular customer. Generally speaking, tools exist that assist with the creation of graphical user interfaces (as examples, the Adobe™ Dreamweaver™ web page designer and the Microsoft™ Visual Basic™ programming language). However, existing tools also present a bewildering array of design options that may not always be appropriate for a particular application. 
     A need exists to solve this problem and others previously experienced with graphical user interface design. 
     SUMMARY 
     A page design system addresses the need to constrain modification of pages of a graphical user interface in an appropriate manner. The graphical user interface includes pages and display groups within each page, and the page design system permits each individual page to be modified to suit the needs of a particular customer. So that the pages do not depart from their fundamental purpose to too great of an extent, the page design system guides and constrains the modifications to each page. In particular, the page design system constrains customization of each display group according to established definitions of admissible graphical user interface elements that are appropriate for each page and each display group of elements within the page. 
     Other systems, methods, features and advantages will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The system may be better understood with reference to the following drawings and description. In the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1  shows a first example of a user interface for a page designer. 
         FIG. 2  shows a second example of a user interface for a page designer. 
         FIG. 3  shows a third example of a user interface for a page designer. 
         FIG. 4  shows a system implementation of a page designer. 
         FIG. 5  shows page design logic that may be implemented in a page design system. 
         FIG. 6  shows example database tables for implementing a standard data object. 
         FIG. 7  shows example database tables for implementing a standard data object. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a graphical user interface (GUI)  100  for a configuration console application (“GUI  100 ”), and in particular for a page designer application within the configuration console. The GUI  100  includes a navigation pane  102  of navigation selections  104  such as “Home”, “Data Dictionary”, “Action Points”, and “Page Designer”. Each navigation selection  104  navigates the configuration console application between different specialized applications centrally managed under the configuration console application. The navigation selection “Page Designer” is shown currently selected, and  FIGS. 1-3  show GUIs of the page designer application. 
     The GUI shown in  FIG. 1  displays a GUI selection palette  106 , a GUI page  108 , and a configuration palette  110 . The GUI page  108  shows, in the example shown in  FIG. 1 , a Policy Details GUI page for an insurance application. The page designer application facilitates constrained customization of GUI pages. Although the example of an insurance application is used below, the GUI pages may be tailored to any application. 
     The Policy Details page includes display groups, four of which are labeled  112 , “Policy Information”;  114 , “Additional Policy Information”;  116 , “Producer Information”; and  118 , “Additional Maintenance Marketing Information”. A GUI page for an application may include any number of display groups. Any of the display groups may organize specific GUI elements together under the display group. The organization may be visual, for example, in which the organized GUI elements are grouped together for display, such as within a displayed boundary (e.g. a shape such as a rectangle drawn around the elements); logical, for example, in which the organized GUI elements are linked together in a functional way; or implemented in other ways. Thus, the display group represents a section on an application page. Typically, the application groups GUI elements logically into these sections. The GUI elements appear grouped together in display groups within the page designer application. For example, the Additional Policy Information display group  116  visually organizes together the Custom GUI element  120 , the Excluded Driver GUI element  122 , and the Additional Insured GUI element  124 . 
     The GUI elements may vary widely in form and function. Examples of GUI elements include: text boxes, read-only text fields, display text, number fields, and description text. Additional examples of GUI elements include date fields, checkboxes, combo boxes, multi-select combo boxes, radio buttons and hyperlinks. 
     As explained in more detail below, the page designer application applies standard data objects and custom data objects to constrain customization of the GUI page  108 . A standard data object links to the GUI page  108  and establishes permissible GUI elements with respect to the GUI page  108  as a whole. In other words, the standard data objects define GUI elements that are allowed to appear in any display group present in a particular GUI page. A custom data object links to one or more particular display groups and establishes permissible GUI elements specifically respect to those display groups. In other words, the custom data object defines GUI elements that are allowed to appear in particular display groups. Accordingly, as the designer selects different display groups in the GUI page  108  to customize, the admissible GUI elements for the selected display group change depending on the custom data objects linked to the selected display group. More specifically, the page design logic determines that a particular display group is selected from among multiple display groups, determines the custom data objects linked to the display group, and determines the permissible GUI elements with respect to the selected display group established by the custom data objects linked to the selected display group (in addition to the permissible GUI elements defined by the standard data objects). 
     As mentioned above, the page designer application displays the GUI page  108 , the display groups  112 - 118  in the GUI page, and the GUI selection palette  106 . The page design logic that implements the page designer application analyzes the custom data objects and the standard data objects to determine how to constrain customization of the GUI page  108 . In particular, the page design logic populates the GUI selection palette  106  with selections of admissible GUI elements, such as the Lien Holder GUI element selection  126 . The admissible GUI elements include the permissible GUI elements established with respect to the GUI page  108  by the standard data objects and the permissible GUI elements with respect to the selected display group established by the custom data objects. The page design logic constrains customization of the selected display group to the admissible GUI elements in the GUI selection palette  106 . 
     Further with regard to the GUI selection palette  106 , the Pages selector  128  may be a drop down list of the pages defined in the application. The designer may then select any page desired to configure from the drop down list. The Available Fields selector  130  may present a list of permissible GUI elements (e.g., data fields) defined by the custom and standard data objects for a particular selected page. Custom selectors, such as the Additional Policy Fields selector  132  may display a list of permissible GUI elements for a particular selected display group such as the Additional Policy Information display group  114 . The permissible GUI elements displayed in the selector  132  may then change depending on the selected display group and the custom data objects defined for the selected display group (the standard data objects are defined for the selected page as a whole and are therefore consistently display regardless of which display group is selected). The system may, if desired, further constrain configuration by preventing the same permissible GUI element from being added twice to the same page. The Policy Fields selector  134  may display a drop down list of standard data objects for a particular page. 
     In one implementation, the page design logic organizes the GUI selection palette  106  by custom data objects. For example, the GUI selection palette  106  may include an expandable/collapsible entry for any given custom data object, under which are organized the permissible GUI elements defined by that custom data object. The GUI selection palette  106  may include separate links or other mechanisms to switch display to permissible GUI elements defined by custom data objects or standard data objects. 
     There may be multiple custom data objects that each establish permissible GUI elements with respect to the selected display group. In such cases, the page design logic may populate the GUI selection palette  106  with the permissible GUI elements from each custom data object. The page design logic accepts from the designer a selection of a specific admissible GUI element from among the admissible GUI elements in the GUI selection palette  106  and permits the designer to add the specific admissible GUI element to the selected display group (e.g., through a drag and drop, double click, or other operation).  FIG. 2  shows an example in which the designer has added the permissible Lien Holder GUI element  202  from the GUI selection palette  106  to the Additional Policy Information display group  114 . 
     In some implementations, the page designer application may setup data type definitions that establish allowable data types for the admissible GUI elements. The page design logic may then interact with the designer to customize GUI elements by assigning a designer selected data type definition to the specific admissible GUI element that the designer has added to a display group. Given the selected data type definition, the page design logic may also accept, from the designer, GUI element customization information constrained by the selected data type definition. 
     To support the customization, the page design logic may establish a correspondence table from data types to available GUI controls. Table 1 shows an example of the correspondence table that the page design logic may implement. In other words, when a designer chooses a particular data type definition for the GUI element to the selected display group, the page design logic may then allow the designer, as a customization, to select between various available controls that the GUI element will implement, as constrained by the correspondence table for the selected data type definition. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Data Type 
                 Available GUI controls 
               
               
                   
                   
               
             
             
               
                   
                 Phone 
                 Text Box, Read-Only Text Field, 
               
               
                   
                   
                 Display Text 
               
               
                   
                 Number 
                 Number 
               
               
                   
                 Text 
                 Description Text, Read-Only Text 
               
               
                   
                   
                 Field, Text Box, Display Text 
               
               
                   
                 Date 
                 Date 
               
               
                   
                 Valid Value List 
                 Checkbox, Combo Box, Multi-Select 
               
               
                   
                   
                 Combo Box, Radio Button 
               
               
                   
                 Single Valid Value 
                 Display Text, Read-Only Text Box 
               
               
                   
                 Boolean 
                 Checkbox, Combo Box, Radio Button 
               
               
                   
                 Time 
                 Time 
               
               
                   
                 Currency 
                 Currency 
               
               
                   
                 Year 
                 Text Box, Read-Only Text Field, 
               
               
                   
                   
                 Display Text 
               
               
                   
                 Email 
                 Text Box, Read-Only Text Field, 
               
               
                   
                   
                 Display Text 
               
               
                   
                 Web Address 
                 Hyperlink, Text Box, Read-Only Text 
               
               
                   
                   
                 Field, Display Text 
               
               
                   
                   
               
             
          
         
       
     
     Alternatively or additionally, the page design logic may establish a correspondence table from available GUI controls to data types. Table 2 shows an example of the correspondence table that the page design logic may implement. In other words, when a designer chooses a particular GUI control for the new GUI element added to the selected display group, the page design logic may then allow the designer, as a customization, to select between various available data types established in the correspondence table for the selected GUI control. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 GUI control 
                 Available Data Types 
               
               
                   
                   
               
             
             
               
                   
                 Currency 
                 Currency 
               
               
                   
                 Checkbox 
                 Boolean, Valid Value List 
               
               
                   
                 Combo Box 
                 Boolean, Valid Value List 
               
               
                   
                 Date 
                 Date 
               
               
                   
                 Description Text 
                 Text 
               
               
                   
                 Display Text 
                 Phone, Text, Single Valid Value, Year, 
               
               
                   
                   
                 Email, Web Address 
               
               
                   
                 Hyperlink 
                 Web Address 
               
               
                   
                 Multi-Select Combo Box 
                 Valid Value List 
               
               
                   
                 Number 
                 Number 
               
               
                   
                 Radio Button 
                 Valid Value List, Boolean 
               
               
                   
                 Read-Only Text Field 
                 Phone, Text, Single Valid Value, Year, 
               
               
                   
                   
                 Email, Web Address 
               
               
                   
                 Text Box 
                 Phone, Text, Year, Email, Web 
               
               
                   
                   
                 Address 
               
               
                   
                 Time 
                 Time 
               
               
                   
                   
               
             
          
         
       
     
       FIG. 3  shows an example of the GUI element property customization. In particular,  FIG. 3  shows that the page design logic has expanded the configuration palette  110  to include property customization selections  302  for the Lien Holder GUI element  202 . In the example shown in  FIG. 3 , the customization selections  302  include a Field Properties selection, a Field Display Properties selection, a Valid Values selection, and a Display Rules selection. The Field Properties selection may include customization options for viewing and modifying global properties of the field itself rather than display properties of a particular instance of the field on the page (which are shown in the Field Display Properties selection). These global properties are characteristics such as the name of field, business data type (e.g., is it a Text field or Numeric or a set of values to be displayed in a combo box, and so on), Effective and Expiration Dates for the field, and other properties. Characteristics that can be customized once the field has been created and saved, include, as examples, the Description for the field, the Effective and Expiration Dates for the field, Field Length (max length), Default Value, Edit Authorization (i.e., which user types can edit this field), View Authorization (i.e., which user types can see this field), and Help Text for the field. When the field is first created, all the properties in the Field Properties selection may be set as editable/customizable. 
     The Field Display Properties selection may include customization options for a label for the GUI element  202 , the type of GUI element (e.g., a text box), the GUI element width, or other customization options. The Valid Values selection may include customization options for limiting the values that may be entered into the GUI element  202 . In particular, the Valid Values selection shows the valid values which are associated to this GUI element (i.e., if the GUI element is a combo box, this shows the values that may appear in the combo box). The user can customize individual valid values through the Valid Values selection (including expiring the ones they no longer want to appear in the combo box) as well as add additional valid values. The user can also relate valid values to other valid values. For example, if there are GUI elements for State and County, the user can relate State valid values to applicable County valid values so that if user selects a State, the GUI element for County will only contain applicable Counties. 
     The Display Rules selection may include customization options that specify when the GUI element  202  is displayed. In particular, the Display Rules selection allows the user to configure when the selected GUI element is hidden or disabled. The default behavior may be, for example, to always to show and enable (make editable) the GUI element. The Display Rules selection allows the user to always hide or hide based on an expression (e.g., a logical condition that the user specifies) as well as always disable or disable based on expression (e.g., a logical condition that the user specifics). 
     Additional, fewer, or different property customization options may be present, and they may change depending on the type of GUI element to which they apply. For example, a text box GUI element may have field width or label property customization options, while a combo box GUI element may have property customization options that define the entries in the combo box, how they are formatted and displayed, and other customization options. 
       FIG. 4  shows a system implementation  400  of a page designer (“system  400 ”). The system  400  includes a processor  402 , a memory  404 , and a data dictionary  406 . A local or remote display  408  may display the configuration console application, including the various applications within the console, such as the page designer application. The processor  402  executes the page design logic  406  to interact with a designer to facilitate constrained customization of GUI pages as explained above. 
     To that end, the memory  404  stores the information on which the page design logic  406  operates. For example, the page design logic  406  may store, define, read or modify, in the memory  404 , the GUI selection palette  409 , GUI page  410 , customization palette  411 , standard data objects  412 , and custom data objects  414 . As shown in  FIG. 4 , the page design logic  406  populates the GUI selection palette  408  with permissible display group GUI elements (“PDGEs”), two of which are labeled PDGE  416  and PDGE  418 . There may be any number, including zero, of such PDGEs for any given display group. The page design logic  406  also populates the customization palette  411  with customization options  413  appropriate for a selected GUI element. 
     The GUI page  410  includes any number of display groups. Three such display groups are labeled in  FIG. 4  as display groups  420 ,  422 , and  424 . The display groups organize GUI elements. There may be any number of GUI elements organized under a display group. As examples, display group  420  includes GUI elements  426 ,  428 ,  430 ,  432 , and  434 ; display group  422  includes GUI elements  436  and  438 ; and display group  424  includes the GUI element  440 . 
     As noted above, the standard data object  412  is linked to the GUI page  410  to define permissible display group GUI elements for the GUI page  410  as a whole. Three PDGEs  442 ,  444 , and  446  from the standard data object  412  are shown in  FIG. 4 . Any of the PDGEs may be defined in advance. In this way, the designer has some flexibility to change the design of the GUI pages, yet cannot stray too far from the original design of the GUI pages  410 . Similarly, the custom data object  414  defines PDGEs  448 ,  450 , and  452  that are available for the display groups to which the custom data object is specifically linked. The system  400  may implement the links as pointers, database fields defined in tables (e.g., as described in more detail below) that represent the standard data objects  412  and custom data objects  414  (e.g, with a database field specifying identifiers of linked GUI pages and display groups), or in other ways. 
       FIG. 5  shows page design logic  500  that may be implemented in a page design system (e.g., as a program for the page design logic  406  running in the memory  404  and executed by the processor  402 ). The page design logic  500  stores, in the memory  404 , the GUI pages  410  for the application that will be customized ( 502 ). The GUI pages  410  may be expressed in many different manners, such as Hypertext Markup Language (HTML), eXtensible Markup Language (XML), or other manners. The GUI pages  410  include display groups which are also present in the memory  404 . The page design logic  500  determines which GUI page and display group that the designer has selected to customize ( 504 ). The page design logic  500  further reads the custom data objects  414  and standard data objects  412  for the selected GUI page and the display groups from the data dictionary  406  into the memory  404  ( 506 ). 
     The page design logic  500  displays the GUI page (e.g., on the display  408 ), including the display groups defined for the GUI page, as well as the GUI selection palette  408  and configuration palette  409  ( 508 ). Based on the selected GUI page, display group, and associated custom and standard data objects, the page design logic  500  populates the GUI selection palette  409  with permissible display group elements ( 510 ). The page design logic  500  constrains customization of the GUI page to the permissible display group elements. To that end, the page design logic  500  may accept a selection of a specific admissible GUI element from among the admissible GUI elements ( 512 ) and add the specific admissible GUI element to the selected display group ( 514 ). 
     In addition, the page design logic  500  may accept a selection of, and assign a specific data type definition to, the selected permissible GUI element ( 516 ). The data type definition may contribute to determining the customization options available for the GUI elements. Accordingly, the page design logic  500  populates the customization palette  411  with the permissible customization options  413  ( 518 ). The page design logic  500  accepts customization information from the designer constrained by the permissible customization options  413  and sets the GUI element properties accordingly ( 520 ). 
       FIG. 6  shows an example database implementation  600  for standard data objects, and also for supporting custom data objects. In particular, the example database implementation  600  includes several database tables that support the creation, modification, and manipulation of standard data objects and customer data objects. As an overview, the database implementation  600  includes a data item table  602  (DATAITEM), data item fully qualified name table  604  (DATAITEM_FQN), a data item fully qualified name validation table  606  (DATAITEM_FQN_VLDTN), a data item localized table  608  (DATAITEM_LCL), and a physical data item table  610  (DATAITEM_TBL). The database implementation  600  further includes a data item type table  612  (DATAITEM_TYP), a data item type localized table  614  (DATAITEM_TYP_LCL), a datatype table  616  (DATATYP), and a datatype localized table  618  (DATATYP_LCL). These tables are summarized in Table: Standard Data Object, below, and described in more detail below. 
     
       
         
               
               
             
           
               
                 TABLE STANDARD DATA OBJECT 
               
               
                   
               
               
                 Description 
                 Table Name 
               
               
                   
               
             
             
               
                 Defines data items in the system. A data item may be a data 
                 Data Item (602) 
               
               
                 element, extended data element, logical table or column, alias or 
               
               
                 other data item. 
               
               
                 Defines the fully-qualified name for a data item. For example, if 
                 Data Item Fully Qualified 
               
               
                 the “State” data element exists in a data item then this table 
                 Name (604) 
               
               
                 would specify the full “path” (e.g., Contract.Address.State). 
               
               
                 Specifies the validations that should be performed for a specific 
                 Data Item Fully Qualified 
               
               
                 data item. 
                 Name Validation (606) 
               
               
                 Contains locale-specific information about a data item, to provide 
                 Data Item Localized (608) 
               
               
                 language or other localization characteristics of the data item. 
               
               
                 This table lists the physical tables (as defined elsewhere in the 
                 Data Item Table (610) 
               
               
                 data model) that the given data item has the primary keys for. 
               
               
                 The data item may be defined as a “Data Group” 
               
               
                 (DATAITEM.C_DATAITEM_TYP = ‘DATAGRP’) data item. 
               
               
                 Defines the various types of data items that are defined in the 
                 Data Item Type (612) 
               
               
                 Data Item table. 
               
               
                 Contains locale-specific information about a Data Item Type 
                 Data Item Type Localized 
               
               
                   
                 (614) 
               
               
                 Defines the data types that are available and used within the 
                 Datatype (616) 
               
               
                 system. This includes, e.g., both core .NET data types and 
               
               
                 application-specific types. 
               
               
                 Contains locale-specific information about a Data Type. 
                 Datatype Localized (618) 
               
               
                   
               
             
          
         
       
     
     The data item table  602  stores both standard and custom data objects, and the permissible GUI elements (e.g., the fields) for both standard and custom objects. For example, to define a standard data object (which may be referenced as a “DTO” below), an application designer may insert the standard data objects and their fields into the data item table  602 . The system  400  may then query the data item table  602  to determine available standard (and custom) data objects and their fields. 
     Table DATAITEM table, below, provides an example of how the data item  602  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE DATAITEM 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This column uniquely identifies the data item. If the data item is a 
                 Data Item Name 
               
               
                 standard data object, then this column is the name of the class (without 
               
               
                 the namespace prefix). If the data item is an Element/property within a 
               
               
                 standard data object then this is the name of the property as specified in 
               
               
                 the code. 
               
               
                 This is a code used for representing a type of Data Item in the data 
                 Data Item Type Code 
               
               
                 dictionary. There is a pre-defined and fixed set of Data Item types that 
               
               
                 the architecture supports. 
               
               
                 This column contains the code that represents the datatype of the data 
                 Datatype Code 
               
               
                 item. The list of valid datatypes is defined in the Datatype table. 
               
               
                 This column will contain the name of a RefData category if the data item 
                 Category Name 
               
               
                 corresponds to a key within a RefData category. For example, if the 
               
               
                 Data Item is “StateCode” then this column might contain the name of a 
               
               
                 RefData category called “States”. This can be used by configuration 
               
               
                 consoles to aid the user when configuring activities, extension points, 
               
               
                 etc. 
               
               
                 If the data item is of type “ALIAS”, then this column contains the name of 
                 Aliased Data Item Name 
               
               
                 the data item that is being aliased. For example, if a standard data 
               
               
                 object data item has a name “CustomerDTO” it may be necessary to 
               
               
                 define an alias of that called “Customer”. In that case, the “Customer” 
               
               
                 data item would be defined of type “ALIAS” and this column would 
               
               
                 contain “CustomerDTO”. 
               
               
                 This is a code that indicates the format mask (defined in a FRMT_MSK 
                 Default Format Mask Code 
               
               
                 table) that, by default, should be used when displaying a formatted value 
               
               
                 for this data item. It is possible for this to be overridden if the data item 
               
               
                 is added to a Display Group. 
               
               
                 This column contains the name of the functional data group that the data 
                 Functional Data Group Code 
               
               
                 item belongs to. This does not necessarily represent a physical group 
               
               
                 and is different than a “data group” type of data item. This column 
               
               
                 provides a way of functionally grouping together similar data items to aid 
               
               
                 in the configuration activities. 
               
               
                 This field contains the code that represents the help text to display for 
                 Help Text Code 
               
               
                 field level help associated with this data time. 
               
               
                 This optionally contains the name of an anchor (location tag) in the help 
                 Help Anchor Name 
               
               
                 text that should be navigated to when the help is displayed. This allows 
               
               
                 a single help entry to contain information for multiple data items and the 
               
               
                 appropriate help section will be navigated to when displayed. 
               
               
                 This column serves two purposes. It identifies the last transaction that 
                 Last Transaction Id 
               
               
                 modified the record. This may tie to the system auditing columns. The 
               
               
                 other purpose of this column is to be the optimistic lock key. 
               
               
                 If this column is not null it contains the code for the Business Data Type 
                 Business Data Type Code 
               
               
                 that was used as the template when creating the Data Item. 
               
               
                   
               
             
          
         
       
     
     Table DATAITEM_FQN table, below, provides an example of how the data item fully qualified name table  604  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE DATAITEM_FQN 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This is the fully qualified name for the data item, e.g., the full listing 
                 Data Item Fully Qualified Name 
               
               
                 of the DTOs in which the data item is located (e.g., 
               
               
                 DTO1.DTO2.DATAITEM). 
               
               
                 Primary key that points to the data item itself in the data item table. 
                 Data Item Name 
               
               
                 Used to set an edit rule that determines, e.g., which users can edit 
                 Edit Authorization Rule Name 
               
               
                 the data item. 
               
               
                 Used to set a real-only rule that determines, e.g., which users have 
                 Read Authorization Rule Name 
               
               
                 read-only access to the data item. 
               
               
                 This column serves two purposes. It identifies the last transaction 
                 Last Transaction Id 
               
               
                 that modified the record. This may tie to the system auditing 
               
               
                 columns. The other purpose of this column is to be the optimistic 
               
               
                 lock key. 
               
               
                 This is the name of the model data service that can be used to 
                 Model Data Service Name 
               
               
                 retrieve the data corresponding to the given data item fully qualified 
               
               
                 name.. 
               
               
                 This is the fully qualified name for the data item, e.g., the full listing 
                 Data Item Fully Qualified Name 
               
               
                 of the DTOs in which the data item is located (e.g., 
               
               
                 DTO1.DTO2.DATAITEM). 
               
               
                 This is a primary key that point to the validation itself in the 
                 Validation Name 
               
               
                 validation table. 
               
               
                   
               
             
          
         
       
     
     Table DATAITEM_FQN_VLDTN table, below, provides an example of how the data item fully qualified name validation table  606  may be implemented. 
     
       
         
               
               
               
             
           
               
                 TABLE DATAITEM_FQN_VLDTN 
               
               
                   
               
               
                 Table Column Name 
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 N_DATAITEM_FQN 
                 This is the fully qualified name for the data item, e.g., 
                 Data Item Fully 
               
               
                   
                 the full listing of the DTOs in which the data item is 
                 Qualified Name 
               
               
                   
                 located (e.g., DTO1.DTO2.DATAITEM). 
               
               
                 N_VLDTN 
                 This is a primary key that point to the validation itself in 
                 Validation Name 
               
               
                   
                 the validation table. 
               
               
                 V_SRT_ORD 
                 This is the sort order of the validations for the data 
                 Sort Order Value 
               
               
                   
                 item fully qualified name (e.g., if the a data item FQN 
               
               
                   
                 has more than one validation, this determines the 
               
               
                   
                 order of those validations for that data item FQN). 
               
               
                 B_RQRD_VLDTN_TYP 
                 If this column is true (1) it indicates that the given 
                 Required Validation 
               
               
                   
                 validation exists to verify the data item contains a 
                 Type Flag 
               
               
                   
                 value. In other words, the data item is required to 
               
               
                   
                 have a value and this validation exists to make sure a 
               
               
                   
                 value exists. 
               
               
                 G_LAST_TXN_ID 
                 This column serves two purposes. It identifies the last 
                 Last Transaction Id 
               
               
                   
                 transaction that modified the record. This may tie to 
               
               
                   
                 the system auditing columns. The other purpose of 
               
               
                   
                 this column is to be the optimistic lock key. 
               
               
                   
               
             
          
         
       
     
     Table DATAITEM_LCL table, below, provides an example of how the data item localized table  608  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE DATAITEM_LCL 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 Primary key that points to the data item itself in the 
                 Data Item Name 
               
               
                 data item table. 
               
               
                 This column contains the identifier of the locale 
                 Locale Id 
               
               
                 that the record is for. This value and other values 
               
               
                 used in other tables may be defined in separate 
               
               
                 table in the system (e.g., a table called LCL). 
               
               
                 This is the description for the data item as shown 
                 Data Item Text 
               
               
                 on the page designer user interface in the Field 
               
               
                 Properties panel Description Field. 
               
               
                 The G_LAST_TXN_ID column serves two 
                 Last Transaction Id 
               
               
                 purposes. It identifies the last transaction that 
               
               
                 modified the record. This may tie to the system 
               
               
                 auditing columns. The other purpose of this 
               
               
                 column is to be the optimistic lock key. 
               
               
                 This is the display name for the data item which 
                 Data Item Display 
               
               
                 may be displayed in the configuration user 
                 Name 
               
               
                 interface. 
               
               
                   
               
             
          
         
       
     
     Table DATAITEM_TBL table, below, provides an example of how the physical data item table  610  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE DATAITEM_TBL 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 Primary key that points to the data item itself in 
                 Data Item Name 
               
               
                 the data item table. 
               
               
                 This is the name of a physical table (defined in 
                 Table Name 
               
               
                 the TBL table) that the given Data Item contains 
               
               
                 the primary keys for. The Data Item may be 
               
               
                 specified, e.g., as “DATAGRP”. This information 
               
               
                 may be used when doing configuration. 
               
               
                 This column serves two purposes. It identifies 
                 Last Transaction Id 
               
               
                 the last transaction that modified the record. This 
               
               
                 may tie to the system auditing columns. The other 
               
               
                 purpose of this column is to be the optimistic 
               
               
                 lock key. 
               
               
                   
               
             
          
         
       
     
     Table DATAITEM_TYP table, below, provides an example of how the data item type table  612  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE DATAITEM_TYP 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This is a code used for representing a type of Data 
                 Data Item 
               
               
                 Item in the database. There may be a pre-defined 
                 Type Code 
               
               
                 and fixed set of Data Item types that the architecture 
               
               
                 supports. 
               
               
                 This column contains the date that the record went into 
                 Begin Date 
               
               
                 effect. It is possible for this date to be in the future. 
               
               
                 The column contains the date the record will expire. 
                 End Date 
               
               
                 This date may be greater than or equal to the 
               
               
                 D_BEG column&#39;s value. Setting this field 
               
               
                 equal to the D_BEG value may logically delete 
               
               
                 the record (e.g., make the record so it was 
               
               
                 never active). 
               
               
                 This column serves two purposes. It identifies the 
                 Last Transaction 
               
               
                 last transaction that modified the record. This may 
                 Id 
               
               
                 tie to the system auditing columns. The other 
               
               
                 purpose of this column is to be the optimistic 
               
               
                 lock key. 
               
               
                   
               
             
          
         
       
     
     Table DATAITEM_TYP_LCL table, below, provides an example of how the data item type localized table  614  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE DATAITEM_TYP_LCL 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This is a code used for representing a type of Data 
                 Data Item 
               
               
                 Item in the data dictionary. There is a pre-defined 
                 Type Code 
               
               
                 and fixed set of Data Item types that the architecture 
               
               
                 supports. 
               
               
                 This column contains the identifier of the locale that 
                 Locale Id 
               
               
                 the record is for. 
               
               
                   
                 Data Item 
               
               
                   
                 Type Text 
               
               
                 This column serves two purposes. It identifies the 
                 Last 
               
               
                 last transaction that modified the record. This may 
                 Transaction 
               
               
                 tie to the system auditing columns. The other 
                 Id 
               
               
                 purpose of this column is to be the optimistic 
               
               
                 lock key. 
               
               
                   
               
             
          
         
       
     
     Table DATATYP table, below, provides an example of how the datatype table  616  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE DATATYP 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This is a code that represents the datatype. Other 
                 Datatype Code 
               
               
                 tables will reference this code. 
               
               
                 This is the fully qualified name for the data type, e.g., 
                 Datatype Fully 
               
               
                 the full listing of the DTOs in which the data type is 
                 Qualified Name 
               
               
                 located (such as DTO1.DTO2.DATATYPE). 
               
               
                 This flag is used to indicate whether the datatype 
                 Allow Extended 
               
               
                 can be used when defining a Data Item of type 
                 Data Flag 
               
               
                 Extended Data (i.e., 
               
               
                 DATAITEM.C_DATAITEM_TYP = ‘EXTDATA’). 
               
               
                 This column serves two purposes. It identifies the 
                 Last Transaction 
               
               
                 last transaction that modified the record. This may 
                 Id 
               
               
                 tie to the system auditing columns. The other 
               
               
                 purpose of this column is to be the optimistic 
               
               
                 lock key. 
               
               
                 This flag is used to indicate whether the datatype 
                 Allow Element 
               
               
                 can be used when defining a Data Item of type 
                 Flag 
               
               
                 Element (i.e., 
               
               
                 DATAITEM.C_DATAITEM_TYP = 
               
               
                 ‘ELEMENT’). 
               
               
                 This flag is used to indicate whether the datatype 
                 Allow Data 
               
               
                 can be used when defining a Data Item of type Data 
                 Group Flag 
               
               
                 Group (i.e., DATAITEM.C_DATAITEM_TYP = 
               
               
                 ‘DATAGRP’). 
               
               
                   
               
             
          
         
       
     
     Table DATATYP_LCC table, below, provides an example of how the datatype localized table  618  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE DATAITEM_TYP_LCL 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This is a code that represents the datatype and is 
                 Datatype Code 
               
               
                 defined in the Datatype table. 
               
               
                 This column contains the identifier of the locale 
                 Locale Id 
               
               
                 that the record is for. 
               
               
                 This is the description of the data item type, which 
                 Datatype Text 
               
               
                 may not be exposed in the page designer user 
               
               
                 interface or other interfaces. 
               
               
                 This column serves two purposes. It identifies the 
                 Last Transaction Id 
               
               
                 last transaction that modified the record. This may 
               
               
                 tie to the system auditing columns. The other 
               
               
                 purpose of this column is to be the optimistic lock 
               
               
                 key. 
               
               
                   
               
             
          
         
       
     
       FIG. 7  shows an example database implementation  700  for custom data objects. In particular, the example database implementation  700  includes several database tables that support the creation, modification, and manipulation of custom data objects. As an overview, the database implementation includes a logical table  702  (LGCL_TBL), a logical table data item table  704  (LGCL_TBL_DATAITEM), and a logical table localized table  706  (LGCL_TBL_LCL). These tables are described in more detail below. 
     Regarding the terminology used below, a logical table is an analog for a custom data object, and a logical column is an analog for a custom field that is included in the custom data object. In one implementation, applications define physical tables that may be extended with logical tables which define custom data objects. For example, if an application includes a physical table storing claim numbers, then a logical table may be defined and linked to the claim number table to define custom fields related to the claim number table. 
     A display group may correspond to one or more logical tables linked to a physical table. The custom fields that a designer may then add to the display group are available based on logical tables associated together into the display group. For example, a separate association table may associate one or more logical tables to a display group so that the display group includes one or more sets of custom fields defined by one or more logical tables. 
     As mentioned above, a logical column may define a custom field. Thus, each time that a custom field is desired to be added, a logical column defining that custom field is added to the logical table. Furthermore, the data item table  602  may store field property data as noted above. More specifically, logical columns are defined in the data item table  602 . When the column is defined it is given a name, description, and data type. A given logical column may be used in multiple logical tables. When a logical column is added to a logical table, that association is stored in the LGCL_TBL_DATAITEM table  604  and a new fully qualified name is created in the form&lt;logical table&gt;.&lt;logical column&gt; and is associated with the logical column&#39;s data item. In addition, the system generates a Logical Column Id, which may be an integer that uniquely identifies the logical column on the logical table. The system may expose public Application Programming Interfaces (APIs) that accept physical table names, logical table names, and logical column names to manipulate logical tables and logical columns. Internally the APIs may translate a logical table and logical column into the appropriate logical column ID. 
     As stated above, a logical column can be added to multiple logical tables. In one implementation, when a logical column is added to multiple different logical tables then each “instance” of that logical column will contain different data. There need not be sharing of data across logical tables. 
     The system  400  allows logical extension of the data model by defining new logical tables that contain one or more logical columns. Data extensibility provides the ability to logically add new fields to an existing physical table in an application database without modifying the physical structure of the table. The physical table is logically extended to support capturing additional related data. A physical table can be extended by more than one logical table. 
     Applications that use data extensibility allow their customers to define new fields without code changes. In one implementation, there are three different tables involved: physical, extension, and logical. The application developer decides which physical tables in the data model can be extended. Extending a physical table may be accomplished by creating an additional database table, the extension table that stores the value for any extended data for the physical table. For example, if the application has a physical table called Customer that stores basic customer information and the application needs to allow clients to define custom data elements related to a customer, the application developer may create an extension table called, e.g., Customer_Extn. The extension table stores the values of all logical columns that a client defines for a customer. The definitions of logical columns are grouped together into logical tables. This allows the client to define many different logical tables that map to the extension table associated with a physical table. For example, the client could define logical tables such as Bank Customer, Person Customer, Airline Customer, and so on, where each logical table has different logical columns, some of which may be in common. 
     An application team may decide what physical tables can be extended and create the corresponding extension table. Consumers of the application may then define the logical tables and fields that belong to each logical table they define. For example, assume that the application is flexible and reusable software for a bank with core functionality that could apply to numerous banks with slightly different business models and terminology. Any bank system has a core Customer table and a set of fields that would most likely apply to all banks (e.g., CustomerId, CustomerType, DateEnrolled, and Address), but frequently, the customer types among the individual banks vary with different processing and terminology. For example, some banks might have only corporate customers while another bank might have individuals, companies, and government as customer types. 
     In this scenario, the developer might want to have a single physical table called Customer with the fixed fields CustomerId, CustomerType, DateEnrolled, and Address. The developer also permits extension of the information collected for each customer type to meet their business needs and terminology. With several customer types, a developer may not want to create new tables for each of these types as they could contain duplicate information. Creating normalized tables that join to a common Customertable may also not be an option as the application may need the capability to add and remove fields in the metadata at design-time so the customer site can customize the application. The runtime can then automatically retrieve and display data without requiring modification to the data access service, business service, or web page. 
     Table Custom Data Object provides an example of the tables that may be used to implement custom data objects. 
     
       
         
               
               
             
           
               
                 TABLE CUSTOM DATA OBJECT 
               
               
                   
               
               
                 Description 
                 Table Name 
               
               
                   
               
             
             
               
                 Contains the definition of a Logical Table. A physical 
                 Logical Table 
               
               
                 table that has been enabled for extensibility will have 
                 (702) 
               
               
                 a corresponding “extension table” (which is also a 
               
               
                 physical table). The application and clients can define 
               
               
                 one or more “Logical Tables” that will use the 
               
               
                 physical extension table for storing data. 
               
               
                 This contains the list of fields that are part of a given 
                 Logical Table 
               
               
                 logical table. In other words, this table lists the 
                 Data Item (704) 
               
               
                 “columns” of each logical table. 
               
               
                 Contains locale-specific information about a Logical 
                 Logical Table 
               
               
                 Table, to provide language or other localization 
                 Localized (706) 
               
               
                 characteristics of the table. 
               
               
                   
               
             
          
         
       
     
     Table LGCL_TBL, below, provides an example of how the logical table  702  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE LGCL_TBL 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This column contains the name of the logical table. A 
                 Logical Table 
               
               
                 physical table can have multiple logical tables 
                 Name 
               
               
                 defined to extend it. 
               
               
                 This is the name of the physical table (defined 
                 Table Name 
               
               
                 elsewhere in the system) that the logical table extends. 
               
               
                 This column contains the date that the record went 
                 Begin Date 
               
               
                 into effect. It is possible for this date to be in the 
               
               
                 future. 
               
               
                 The column contains the date the record will expire. 
                 End Date 
               
               
                 This date may be controlled to be greater than or 
               
               
                 equal to the Begin Date column&#39;s value. Setting 
               
               
                 this field equal to the Begin Date value may cause 
               
               
                 logical deletion of the record (e.g., make the record 
               
               
                 so it was never active). 
               
               
                 This column serves two purposes. It identifies the 
                 Last 
               
               
                 last transaction that modified the record. This may 
                 Transaction 
               
               
                 tie to the system auditing columns. The other purpose 
                 Id 
               
               
                 of this column is to be the optimistic lock key. 
               
               
                   
               
             
          
         
       
     
     Table LGCL_TBL_DATAITEM, below, provides an example of how the logical table data item  704  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE LGCL_TBL_DATAITEM 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This is the name of the logical table (as defined in the LGCL_TBL table) 
                 Logical Table Name 
               
               
                 that the data item (i.e., logical column) is to be associated with. 
               
               
                 Primary key that points to the data item itself in the data item table. 
                 Data Item Name 
               
               
                 This is the fully qualified name of the data item. 
                 Data Item Fully Qualified 
               
               
                   
                 Name 
               
               
                 This is the name of the physical table (defined elsewhere in the system) 
                 Table Name 
               
               
                 that the logical table extends. This column exists on this table so that a 
               
               
                 unique constraint may be enforced that prevents the same data item to 
               
               
                 be part of two different Logical Tables that extend the same physical 
               
               
                 table. 
               
               
                 The column contains the date the record will expire. This date may be 
                 End Date 
               
               
                 controlled to be greater than or equal to the Begin Date column&#39;s value. 
               
               
                 Setting this field equal to the D Begin Date value will logically delete the 
               
               
                 record (e.g., make the record so it was never active). 
               
               
                 This column contains the date that the record went into effect. It is 
                 Begin Date 
               
               
                 possible for this date to be in the future. 
               
               
                   
                 Default Value Text 
               
               
                 This is one of four “default value” columns on the table. This allows a 
                 Default Decimal Value 
               
               
                 new logical column to be added to an existing logical table along with a 
               
               
                 default value. This is similar to adding a new column to a physical table 
               
               
                 (that already contains data) and specifying a default value for it. This 
               
               
                 column is used for storing the default of a logical column that is a 
               
               
                 decimal datatype. If the logical column&#39;s datatype is not decimal or no 
               
               
                 default is needed then this column must be null. 
               
               
                   
                 Default Value Timestamp 
               
               
                   
                 Default Value Number 
               
               
                 This column serves two purposes. It identifies the last transaction that 
                 Last Transaction Id 
               
               
                 modified the record. This may tie to the system auditing columns. The 
               
               
                 other purpose of this column is to be the optimistic lock key. 
               
               
                   
               
             
          
         
       
     
     Table LGCL_TBL_LCL, below, provides an example of how the logical table localized  706  may be implemented. 
     
       
         
               
               
             
           
               
                 TABLE LGCL_TBL_LCL 
               
               
                   
               
               
                 Description 
                 Column Name 
               
               
                   
               
             
             
               
                 This is the name of the logical table. 
                 Logical Table 
               
               
                   
                 Name 
               
               
                 This column contains the identifier of the locale that 
                 Locale Id 
               
               
                 the record is for, which may be defined in another 
               
               
                 system table. 
               
               
                 This is the description of the Logical Table. As 
                 Logical 
               
               
                 shown in the Configuration Console, this is the 
                 Table Text 
               
               
                 description field for the Custom Data Object. 
               
               
                 This column serves two purposes. It identifies the 
                 Last 
               
               
                 last transaction that modified the record. This may 
                 Transaction Id 
               
               
                 tie to the system auditing columns. The other purpose 
               
               
                 of this column is to be the optimistic lock key. 
               
               
                 This is a localized version of the name of the logical 
                 Logical Table 
               
               
                 table that can be displayed to users. 
                 Display Name 
               
               
                   
               
             
          
         
       
     
     Below is example pseudo code for inserting a new logical column to define a custom field for Eye Color: 
     
       
         
               
             
           
               
                   
               
             
             
               
                   LogicalColumnDTOeyeColor = new LogicalColumnDTO( ) 
               
               
                   { 
               
               
                     Set name for new logical column to EyeColor; 
               
               
                     Set BeginDate to the earliest date allowed; 
               
               
                     Set EndDate to the highest date allowed; 
               
               
                     Set Data Type for new logical column to String; 
               
               
                     Assign eye color logical column to desired logical table (e.g., the 
               
               
                 Resident table); 
               
               
                     Assign eye color logical column to desired functional data group 
               
               
                 (e.g., the Customer Data functional data group); 
               
               
                     Assign locale specific information for the eye color logical 
               
               
                 column by: 
               
               
                       Set a locale ID (e.g., to 1033 for English - US); 
               
               
                       Set a description for the eye color logical column which 
               
               
                 will be shown in the page designer field properties panel in the description 
               
               
                 field (e.g., “The color of the person&#39;s eyes”); 
               
               
                       Assign a display name for the new eye color logical column 
               
               
                 which will be shown in the page designer field properties panel in the field 
               
               
                 name field (e.g., “Eye Color”); 
               
               
                 } 
               
               
                   
               
             
          
         
       
     
     Insert new logical column into the tables noted above (e.g., by calling an application programming interface function that inserts the column). 
     In the description above, one aspect of the page design innovation related to a method for guided design of pages for a graphical user interface (GUI) to an application. The method included defining, in a memory, page design logic, a GUI page, and a display group within the GUI page. The display group organizes specific GUI elements together under the display group. Also defined in the memory is a standard data object linked to the GUI page. The standard data object establishes permissible GUI elements with respect to the GUI page as a whole. Furthermore, a custom data object is defined in memory and is linked to the display group. The custom data object establishes permissible GUI elements with respect to the display group specifically. 
     The method further includes displaying the GUI page, the display group in the GUI page, and a GUI selection palette. The page design logic is executed with a processor in communication with the memory to populate the GUI selection palette with admissible GUI elements and constrain customization of the display group to the admissible GUI elements in the GUI selection palette. The admissible GUI elements populated into the GUI selection palette include the permissible GUI elements with respect to the GUI page, and the permissible GUI elements with respect to the display group. 
     The custom data object may be one of multiple custom data objects that each establishes permissible GUI elements with respect to the display group. The page design logic may then populate the GUI selection palette with the permissible GUI elements from each custom data object. To facilitate constrained customization, the page design logic may accept a selection of a specific admissible GUI element from among the admissible GUI elements and add the specific admissible GUI element to the display group. 
     The admissible GUI elements of the custom data object may vary widely. The memory may also store data type definitions that establish the data types for the admissible GUI elements. The method may also assign a selected one of the data type definitions to the specific admissible GUI element and accept GUI element customization information constrained by the selected one of the data type definitions. 
     The display group may be one of multiple display groups within the GUI page. Each display group may organize specific GUI elements together under that display group. The method may then execute the page design logic to determine that the display group is selected from among the multiple display groups, determine that the custom data object is linked to the particular selected display group, and determine the permissible GUI elements with respect to the display group established by the custom data object. 
     In another aspect, a page design system includes a processor and a memory in communication with the processor. The memory stores the GUI page, the display group, the standard and custom data objects, and the page design logic. The system executes the page design logic to perform the processing noted above with respect to constrained customization of the display group. In yet another aspect, a product comprises a machine readable medium and logic stored on the medium, that, when executed by a processor, is operable to cause a page design system to perform the processing noted above with respect to constrained customization of the display group. 
     The logic and processing described above may be encoded or stored in a machine-readable or computer-readable medium such as a compact disc read only memory (CDROM), magnetic or optical disk, flash memory, random access memory (RAM) or read only memory (ROM), erasable programmable read only memory (EPROM) or other machine-readable medium as, for examples, instructions for execution by a processor, controller, or other processing device. The medium may be implemented as any device or tangible component that contains, stores, communicates, propagates, or transports executable instructions for use by or in connection with an instruction executable system, apparatus, or device. Alternatively or additionally, the logic may be implemented as analog or digital logic using hardware, such as one or more integrated circuits, or one or more processors executing instructions, or in software in an application programming interface (API) or in a Dynamic Link Library (DLL), functions available in a shared memory or defined as local or remote procedure calls, or as a combination of hardware and software. 
     The logic and processing described above may include additional or different logic and may be implemented in many different ways. A processor may be implemented as a controller, microprocessor, microcontroller, application specific integrated circuit (ASIC), discrete logic, or a combination of other types of circuits or logic. Similarly, memories may be DRAM, SRAM, Flash, or other types of memory. Parameters (e.g., conditions and thresholds) and other data structures may be separately stored and managed, may be incorporated into a single memory or database, or may be logically and physically organized in many different ways. Programs and instructions may be parts of a single program, separate programs, implemented in libraries such as Dynamic Link Libraries (DLLs), or distributed across several memories and processors. 
     While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.