Abstract:
A system and method that provides a platform-neutral shell application for a user interface is provided. The platform neutral shell application is performed in a way that prevents the user from accessing the underlying operating system. The desktop shell application executes in a middleware application. The operating system residing on the client computer system is booted. The middleware application is loaded on the operating system platform. The middleware application is programmed for the particular operating system being used by the client. The shell application is loaded on the middleware application. The shell application prevents the user from accessing the underlying operating system by maximizing the window in which the shell application is running, pinning the shell application window to the foreground, and removing controls from the desktop window would otherwise allow the user to bypass the desktop shell.

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field 
   The present invention relates in general to a system and method for controlling user access to a computer operating environment. In particular, the present invention relates to a system and method for providing a platform-neutral shell application that prevents user access to an underlying operating system. 
   2. Description of the Related Art 
   Modern computer software systems often include distributed computing components such as client computer systems and server computer systems. Large organizations may, through time, deploy a number of operating system environments on computer systems distributed throughout the organization. For example, one area of the organization may use Microsoft Windows™ based operating systems on client computers, while another area may use a UNIX-based operating system, such as Linux. Areas may choose different operating system platforms based upon the work being performed by such areas, or based upon purchasing decisions made by management or IT staff. 
   Computer software systems have computer systems that are often linked to one another using a computer network, such as a local area network (LAN) and/or a wide area network (WAN). Computer systems distributed throughout the organization may communicate with one another using a global computer network, such as the Internet. Communication between computer systems, also called nodes, may be encrypted using technology such as Virtual Private Networks (VPNs) that use encryption to safeguard data that travels over the Internet. In a client/server environment, end-users typically use client computer systems to communicate with applications stored on server computer systems using the computer network. 
   One challenge in developing software that is deployed on a variety of operating system platforms is designing a user interface that is similar across the various platforms. An enterprise-based system is often deployed across a variety of operating systems. Users of the enterprise-based application are more efficient and productive if the interface, or “look and feel”, of the application remains consistent regardless of the underlying operating system. In addition, a challenge of traditional systems is providing a consistent interface for launching native applications. In a banking example, a teller function may be a native application with a different native application used depending on the underlying operating system. Interface consistency and a common look and feel are helpful, therefore, in launching native applications from a variety of operating systems. 
   Another challenge in developing software that is deployed on a variety of platforms, is insulating the end-user from the underlying operating system. The computer systems distributed throughout the organization often allow the end-user to access the underlying operating system. As a result, end-users make changes to the operating system attributes and may deliberately or unintentionally add or delete files stored on the computer system used by the end-user. These changes may detrimentally affect the operation of the end-user&#39;s computer. In addition, these changes are often unexpected, and therefore unanticipated, by IT staff. As a result, IT staff may spend considerable time analyzing and troubleshooting the client computer system. This challenge is aggravated in environments where more than one person, or user, uses the same computer system to perform their job functions. 
   What is needed, therefore, is a system and method that provides a platform-neutral desktop environment that is deployed on client computer systems. Furthermore, what is needed is a system and method that locks the platform-neutral desktop environment, thus preventing the end-user from making changes to the computer&#39;s underlying operating system. 
   SUMMARY 
   It has been discovered that the aforementioned challenges are resolved using a system and method that provides a platform-neutral shell application for a user interface. The platform neutral shell application is performed in a way that prevents the user from accessing the underlying operating system. 
   The desktop shell application executes as a middleware application, such as a Java virtual machine (JVM). The operating system residing on the client computer system is booted when the user turns the client computer system on, or resets the client computer system. The virtual machine middleware application (e.g., JVM) is loaded on the operating system platform. The virtual machine middleware application is programmed for the particular operating system being used by the client. The virtual machine middleware application is adapted to run platform-neutral software applications (e.g., Java applications). The shell application is invoked on the virtual machine middleware application. The shell application prevents the user from accessing the underlying operating system. The user is prevented from accessing the underlying operating system by maximizing the window in which the shell application is running, pinning the shell application window to the foreground, and removing controls from the desktop window which would otherwise allow the user to bypass the desktop shell. 
   In one embodiment, the platform-neutral shell application is used to receive and display desktop components included in self-contained desktop packages. The desktop components correspond to the functions performed by the user. In a banking example, one set of desktop components are provided for a teller, another set of desktop components are provided for a loan officer, and a third set of desktop components are provided for a branch manager. The desktop shell application receives the self-contained desktops from a server, unpacks the components, and displays them on the desktop shell application window. In addition, a user may perform multiple roles, in which case the user receives multiple desktops corresponding to the different roles. The desktop shell application provides a pop-up window allowing the user to switch from one set of desktop components to another. 
   The foregoing is a summary and thus contains, by necessity, simplifications, generalizations, and omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the present invention, as defined solely by the claims, will become apparent in the non-limiting detailed description set forth below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention may be better understood, and its numerous objects, features, and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference symbols in different drawings indicates similar or identical items. 
       FIG. 1  is a network diagram of a computer system using self-contained desktops; 
       FIG. 2  is a block diagram of components included in providing self-contained desktops; 
       FIG. 3  is a high level flowchart showing administrator steps taken to provide self-contained desktops; 
       FIG. 4  is a flowchart showing administrator steps taken to set up a particular site; 
       FIG. 5  is a flowchart showing administrator steps taken to set up a user; 
       FIG. 6  is a flowchart showing administrator steps taken to set up a workstation; 
       FIG. 7  is a flowchart showing administrator steps taken to set up application extensions; 
       FIG. 8  is a flowchart showing administrator steps taken to set up application references; 
       FIG. 9  is a flowchart showing administrator steps taken to create self-contained desktops; 
       FIG. 10  is a flowchart showing steps taken by a server to deliver self-contained desktops to a client; 
       FIG. 11  is a screen layout of a screen used by an administrator to set up a new site; 
       FIG. 12  is a screen layout of a screen used by an administrator to manage desktops and machines for a given site; 
       FIG. 13  is a screen layout of a screen used by an administrator to set up a new user; 
       FIG. 14  is a screen layout of a screen used by an administrator to set up an application that is available as a component within one or more self-contained desktops; 
       FIG. 15  is a screen layout of a screen used by an administrator to set up native applications; 
       FIG. 16  is a screen layout of a screen used by an administrator to manage workstations; 
       FIG. 17  is a flowchart showing steps taken to distribute self-contained desktops to servers; 
       FIG. 18  is a flowchart showing steps taken to distribute self-contained desktops from a server to a client; 
       FIG. 19  is a flowchart showing steps taken to create custom application extensions; 
       FIG. 20  is a flowchart showing an application extension lifecycle; 
       FIG. 21A  is a block diagram showing components and resources being distributed from an administrator to multiple clients; 
       FIG. 21B  is a block diagram showing components and resources being recovered by an administrator from servers following a data loss by the administrator; 
       FIG. 22  is a flowchart showing steps taken by an administrator in distributing self-contained desktops and subsequently recovering self-contained desktops from servers following a disaster event; 
       FIG. 23  is a flowchart showing steps taken by a client to receive and display desktops; 
       FIG. 24  is a flowchart showing steps taken by a server to provide desktop information to a client based on the user&#39;s role and the workstation&#39;s role; 
       FIG. 25  is a block diagram showing processing performed by a server and interaction between the server, clients, and administrator; 
       FIG. 26  is a flowchart showing steps taken by a client in initializing and displaying self-contained desktops; 
       FIG. 27  is a screen layout of a sample desktop displayed on a client workstation along with a pop-up menu of other self-contained desktops available to the client; 
       FIG. 28A  is a hierarchy chart of directories used by the client shell in displaying and managing desktops; 
       FIG. 28B  is a hierarchy chart of sections included with the shell configuration file; 
       FIG. 28C  is a hierarchy chart of objects included in the self-contained desktop file; 
       FIG. 29  is a flowchart showing steps taken to initialize the client to use self-contained desktops; 
       FIG. 30  is a flowchart showing steps taken during client initialization; 
       FIG. 31  is a flowchart showing steps taken during native operating system login; 
       FIG. 32  is a flowchart showing steps taken when invoking the Java shell launcher; 
       FIG. 33A  is a screen layout showing an example of a smart graphical component; 
       FIG. 33B  is a screen layout showing an second example of a smart graphical component; 
       FIG. 34  is a hierarchy chart showing various desktop objects; 
       FIG. 35  is a flowchart showing steps taken in initializing smart graphical components; 
       FIG. 36  is a flowchart showing steps taken in processing display attributes for smart graphical components; 
       FIG. 37  is a flowchart showing steps taken in processing behavior attributes for smart graphical components; and 
       FIG. 38  is a block diagram of an information handling system capable of implementing the present invention. 
   

   DETAILED DESCRIPTION 
   The following is intended to provide a detailed description of an example of the invention and should not be taken to be limiting of the invention itself. Rather, any number of variations may fall within the scope of the invention which is defined in the claims following the description. 
     FIG. 1  is a network diagram of a networked computer system that uses self-contained desktops. Administrator  100  creates self-contained desktops  110  by combining images  115 , application extensions  120 , national language translations  125 , client configuration files  130 , server configuration files  135 , and desktop profile information  140 . Self-contained desktops  110  include all information needed for a client to use components on the client&#39;s workstation given the client&#39;s particular role. 
   Self-contained desktops  110  are transmitted to one or more servers  150  for dissemination to clients. Servers  150  combine user roles  155  with workstation roles  160  to determine which self-contained desktops to send to clients. Clients  165  perform login function  170  during which the user ID, and password are gathered and transmitted to servers  150  to effectuate a login. Clients  165  perform login function  170  during which the user ID and machine ID are gathered and transmitted to servers  150  to receive a list of allowed desktops. 
   Servers  150  receive the user ID, password, and machine ID from clients and determine which self-contained desktops to transmit to the clients based upon the user roles  155  and the workstation roles  160  that correspond to the particular user ID and the particular workstation being used by the client. The identified self-contained desktops are responsively transmitted from server  150  to client  165 . 
   Client  165  performs load shell process  175  to load shell application  180  onto the client workstation. The shell process is an application that is loaded onto a middleware application, such as a Java virtual machine (JVM). In this manner, the shell application appears consistent and substantially similar regardless of the operating system platform being used by the client workstation. Shell application  180  is adapted to retrieve and display self-contained desktops  190 . Client  165  receives self-contained desktops based upon the intersection of the user and the workstation identifiers. The self-contained desktops are received and displayed using process  185 . A given client can therefore utilize multiple self-contained desktops. These self-contained desktops include toolbars, menus, and other graphical user interface items used to communicate with the user. Some of these user interfaces include functionality that communicate with server applications hosted by servers  150 . Other user interfaces include extensions that map to client-based applications  195 . When a user clicks on a desktop component that maps to a client-based application, functionality exists within the self-contained desktop to invoke, or otherwise use, the client-based application. If a client has multiple self-contained desktops at its disposal, the user can switch between the various self-contained desktops by using a menu provided by shell application  180 . For example, in a banking environment if a user is both a loan officer and a branch manager both of the corresponding self-contained desktops for these roles would be loaded into shell  180  provided that the workstation is capable of performing both of these roles. To perform loan officer functions, the user selects the loan officer desktop from shell application  180 . Likewise, to perform branch manager functions, the user selects the branch manager desktop from shell application  180 . In addition, a default role can be provided so that the initially displayed desktop corresponds to the user&#39;s primary, or default, role. 
     FIG. 2  is a block diagram of components included in providing self-contained desktops. Administrator  200  defines a topology, user definitions, site definitions, and desktop definitions. Administrator  200  defines a topology by providing workstation definitions  205 . Workstation definitions  205  include workstation addresses  210  and allowed desktops  215  that define which roles, or desktops, are allowed to be used on the various workstations. For example, in a banking environment a workstation that is located at a teller window may have special equipment, such as a teller box, so that the workstation is capable, or allowed, to perform teller functions. Another workstation, perhaps at a desk away from the teller area, may be incapable of performing teller functions. 
   User definitions  220  are used to define the users of the system and the roles such users perform. User definitions  220  include user data  225  and assigned group data  230 . User data  225  includes user identifiers and user passwords. Assigned group data  230  includes the roles a particular user is allowed to perform. For example, a branch manager may be allowed to perform branch manager, loan officer, and teller functions while a teller may only be allowed to perform teller functions. 
   Site definitions  235  include information about a particular site. In a banking environment, a site may be a branch office of the bank. Site definitions  235  include group desktop map  240  that provides a common desktop for users at a particular site as well as site information  245  that provides details concerning the site. 
   Desktop definitions  250  include components used to create self-contained desktops that are used by clients. Desktop definitions  250  include images  252  that are displayed on the self-contained desktop, and application extensions  254  that provide details about client-based applications that are accessible from the self-contained desktop. Desktop definitions  250  also include resources, such as national language translations  256 , so that users are able to select the resources, such as a language preference, that best fits their needs. Desktop definitions  250  also include client configurations  258  and server configurations  260 . These configurations include information about the components included with a particular self-contained desktop. 
   Administrator  200  creates self-contained desktops and publishes the self-contained desktops on one or more servers  265  that are accessible by clients. Server  265  includes persistent storage  270  and authentication function  280 . Persistent storage  270  includes user data  272 , topology information  274 , and self-contained desktops  276 . The user data and topology data are used to determine which self-contained desktops  276  are allowed to be used by a given client using a given workstation. Server  265  provides desktops which are authorized for particular user/workstation to client  290 . The self-contained desktops are received by the client and displayed on platform independent shell  295 . In this manner, server  265  sends identified desktops to client  290  without regard to the particular operating system platform being used by the client. 
     FIG. 3  is a high level flowchart showing steps taken by the administrator to provide self-contained desktops. Administrator processing commences at  300  whereupon the administrator defines users (predefined process  310 , see  FIG. 5  for further details). The administrator also defines workstations that are used by users of the system (predefined process  320 , see  FIG. 6  for further details). 
   Resources that are needed by clients, such as national language translations, are set up so that the resources can be included in self-contained desktops (predefined process  330 ). Application extensions corresponding to applications available from a workstation are defined (predefined process  340 , see  FIG. 7  for further details). Self-contained desktops are packaged including all of the components needed to perform a particular job role (predefined process  350 , see  FIG. 8  for processing details). 
   A determination is made as to whether a new site is being added (decision  360 ). If a new site is being added, decision  360  branches to “yes” branch  365  whereupon a new site is defined (predefined process  370 , see  FIG. 4  for processing details). On the other hand, if a new site is not being added decision  360  branches to “no” branch  375  bypassing step  370 . 
   The defined desktop is mapped to one or more sites and one or more roles (predefined process  380 ). In this manner, a single desktop can be used at multiple sites for multiple roles. Conversely, a different desktop can be defined and used at each site and for each role. The desktop components are packaged into a self-contained desktop and the self-contained desktop is published to one or more servers for dissemination to the various clients (predefined process  390 , see  FIG. 9  for processing details). Administrator processing ends at  395 . 
     FIG. 4  is a flowchart showing administrator steps taken to set up a particular site. Processing commences at  400  whereupon a unique identifier is assigned to the site (step  405 ). A parent site is identified for the site (step  410 ). For example, a branch office may have a regional office for a parent site. In this manner, the new site can inherit characteristics and attributes from the parent site so that the characteristics and attributes are consistent and do not have to be reentered for each site. A determination is made as to whether a parent site was identified (decision  415 ). If a parent site was identified, decision  415  branches to “yes” branch  418  whereupon policies and desktops for the parent are retrieved (step  420 ). On the other hand, if the parent site was not identified decision  415  branches to “no” branch  422  whereupon the administrator sets the policies and desktops to default values for the site (step  425 ). 
   Policies that were either retrieved or set for a particular site can be modified according to the particular site&#39;s needs (step  430 ). In this manner, a site can have slightly different policies from those of a parent site. Sites have one or more roles that are performed by users working at sites. In a banking environment, a branch office site may have roles such as a teller, a loan officer, and a branch manager. The first role for the site is selected (step  435 ). A determination is made as to whether the role needs to be modified (decision  440 ). If the role needs to be modified, decision  440  branches to “yes” branch  445  whereupon a self-contained desktop is selected for the role (step  450 ). On the other hand, if the desktop does not have to be modified for the role, decision  440  branches to “no” branch  455  bypassing step  450 . In this manner, the child site uses the same desktop as the parent site for a particular role, yet the administrator has the flexibility to assign a different desktop to the child site for a given role. 
   A determination is made as to whether there are more roles for the site (decision  460 ). If there are more roles, decision  460  branches to “yes” branch  465  whereupon the next role for the site is selected (step  470 ) and processing loops back to process the next role. This looping continues until there are no more roles for the site, at which point decision  460  branches to “no” branch  475  whereupon the desktops and other data selected for the site are stored (step  480 ). Processing then returns at  495 . 
     FIG. 5  is a flowchart showing steps taken by the administrator to define a new user. Processing commences at  500  whereupon a unique user identifier, such as a user ID, is assigned to the user (step  505 ). An initial passwords is also assigned to the user (step  510 ). A user name and/or description is also entered for the user (step  515 ). A national language preference is selected for the user (step  520 ). 
   A role is selected for the user (step  525 ) from a list of roles that has been created by the administrator and stored in data store  530 . A determination is made as to whether the selected role is the default role for the user (decision  540 ). If the selected role is the default role for the user, decision  540  branches to “yes” branch  545  whereupon the selected role is assigned as the default role for the user (step  550 ). On the other hand, if the selected role is not the default role, decision  540  branches to “no” branch  555  bypassing step  550 . 
   A determination is made as to whether there are more roles to assign to the user (decision  560 ). If there are more roles to assign to the user, decision  560  branches to “yes” branch  565  which loops back to select and process the next role for the user. This looping continues until there are no more roles to assign to the user, at which point decision  560  branches to “no” branch  570  whereupon the roles assigned to the user are stored (step  580 ). Processing then returns at  595 . 
     FIG. 6  is a flowchart showing steps taken by the administrator to set up a workstation. Processing commences at  600  whereupon and identifier, such as a MAC address, if entered for workstation (step  610 ). A MAC address is a Media Access Control address which is a hardware address that uniquely identifies each node of a computer network. A host, or server, is assigned to the workstation (step  620 ). An IP address is either assigned or retrieved for the workstation (step  630 ). A workstation description is also entered for the workstation (step  640 ). A workstation description may include a description of the workstation&#39;s capabilities, such as whether the workstation includes a bank teller drawer. 
   The first role for the workstation is selected (step  650 ) from a list of roles that was created by the administrator and stored in data store  660 . For example, in a banking environment, roles may include a teller, a loan officer, and a branch manager. One workstation may be capable of performing all three roles, while another is only capable of performing one or two of the roles. Furthermore, confidential or sensitive functions may be restricted to a particular workstation even though other workstations may be physically capable of performing such functions. A determination is made as to whether there are more roles to assign to the workstation (decision  670 ). If there are more roles to assign to the workstation, decision  670  branches to “yes” branch  675  whereupon the next role for the workstation is selected (step  680 ). This looping continues until there are no more roles to assign to the workstation, at which point decision  670  branches to “no” branch  685 . The assigned roles and workstation data are stored (step  690 ) in a nonvolatile storage area. Processing then returns at  695 . 
     FIG. 7  is a flowchart showing steps taken by the administrator to set up application extensions. Application extensions are desktop components that provide access to application programs, such as client-based legacy applications. Processing commences at  700  whereupon an extension identifier is assigned to the particular application extension (step  705 ). An application description is entered describing the corresponding application (step  710 ). A client class for the application extension is also entered (step  715 ). 
   A determination is made as to whether the extension is provided by the system or is provided by the user (decision  720 ). If the extension is provided by the user, decision  720  branches to user branch  725  whereupon the Java archive (JAR) filenames corresponding to the extension are entered (step  730 ). On the other hand, if the extension is system supplied, decision  720  branches to system branch  735  bypassing step  730 . 
   A determination is made as to whether an administrator object oriented class is needed (decision  740 ). If an administrator class is needed, decision  740  branches to “yes” branch  745  whereupon the administrator class name is entered (step  750 ). On the other hand, if an administrator class is not needed decision  740  branches to “no” branch  755  bypassing step  750 . 
   The application extension is created using the supplied information (step  760 ). A determination is made as to whether there are any default properties for the application extension (decision  770 ). If there are default properties, decision  770  branches to “yes” branch  775  whereupon the default properties are entered for the application extension (step  780 ). On the other hand if there are no default properties for the application extension, decision  770  branches to “no” branch  785  bypassing step  780 . 
   The application extension, along with any default properties, is stored (step  790 ) in a nonvolatile storage area. Processing then returns at  795 . 
     FIG. 8  is a flowchart showing administrator steps taken to set up application references. Processing commences at  800  whereupon the type of reference (i.e., the extension type) corresponding to the application reference is selected (step  810 ). A unique application reference identifier is assigned to the application reference (step  820 ). An application description is also provided for the application reference (step  830 ). Icon attributes, such as the icon titles and icon filenames, are also provided (step  840 ). Properties that are specific to the type of the application extension are also entered (step  850 ). The application reference is then stored in a nonvolatile storage area (step  860 ) and processing returns at  895 . 
     FIG. 9  is a flowchart showing steps taken by an administrator to create self-contained desktops. Processing commences at  900  whereupon a unique desktop identifier is assigned to the self-contained desktop (step  905 ). A desktop title and/or description is entered for the desktop (step  910 ). The screen and icon appearance is entered for the desktop (step  915 ). The administrator then selects images, such as icons, backgrounds, etc., to appear on the desktop (step  920 ). These images are selected from desktop component library  925 . The desktop component library  925  includes backgrounds and other images  930 , icons  935 , application references  945 , and resources  955 . 
   Application references that will be available from the desktop are selected (step  940 ) from application references  945  included in desktop component library  925 . In a banking environment, a teller&#39;s desktop can include application references to look up customer bank balances and operate the teller&#39;s cash drawer, while a loan officer&#39;s desktop can include application references that provide access to the bank&#39;s loan approval software application. National language data, such as text and resources, are provided for each supported locale (step  950 ). These resources are selected from resources  955  that are included in desktop component library  925 . 
   The desktop configuration is stored detailing the files and resources included the desktop (step  960 ). A client configuration file describing the desktop is created and the desktop data is packaged (step  970 ) resulting in self-contained desktop  975 . The resulting self-contained desktop is published to client-accessible servers (step  980 ) by transmitting the desktops to servers  990 . Processing then returns at  995 . 
     FIG. 10  is a flowchart showing steps taken by a server to deliver self-contained desktops to a client. Processing commences at  1000  whereupon the server receives a user login and workstation identifier (step  1005 ). The user login includes a user identifier and a user password used to authenticate the user. Roles that have been assigned to the user are retrieved (step  1010 ) from user directory data store  1015 . Roles that have been assigned to the workstation are retrieved (step  1020 ) from topology directory  1025 . 
   A determination is made as to whether any roles assigned to the user match any roles assigned to the workstation (decision  1030 ). If there are no roles in common, decision  1030  branches to “no” branch  1035  whereupon an error is returned to the client (step  1038 ) and processing returns at  1095 . On the other hand, if there are one or more roles in common, decision  1030  branches to “yes” branch  1040  whereupon the first desktop for the selected role is retrieved from desktop/role map  1050  and the corresponding self-contained desktop is retrieved from data store  1055 . A determination is made as to whether there any more roles in common between the user and the workstation (decision  1060 ). If there are more roles in common, decision  1060  branches to “yes” branch  1070  whereupon the next common role is selected (step  1080 ) and processing loops back to retrieve the corresponding self-contained desktop. This looping continues until there are no more roles in common between the user and workstation, at which point decision  1060  branches to “no” branch  1065  whereupon the retrieved desktop identifiers (i.e. those identifiers in common for both the user and the workstation) are sent to the client (step  1090 ). Processing then returns at  1095 . 
     FIG. 11  is a screen layout of a screen used by an administrator to set up a new site (see  FIG. 4  for a corresponding flowchart). The administrator uses screen layout  1100  to define a new site. The administrator enters a unique site identifier in text box  1150 . If the new site is a child of a site that has already been created, the parent site is selected from list box  1105 . List box  1105  includes a list of previously defined site identifiers. Frame  1110  includes policy information that is used for the site. Policy information includes a policy name  1115 , a policy value  1120 , and inheritance data  1125 . Inheritance data  1125  includes inheritance value  1130  and inheritance ancestor  1135 . In the example shown, the policy name is “newbDC” and the value of the policy is inherited from the parent site. The inheritance value is “allow” and the inheritance ancestor is the “root” or uppermost site in the site hierarchy. 
   Desktop frame  1140  includes information about the roles and desktops available at the site. Desktop frame  1140  includes role data  1155 , desktop data  1160 , and inheritance data  1170 . The inheritance data includes the name of the desktop that is inherited  1175  and the name of the ancestor  1180  from which the desktop is inherited. In the example shown, the roles included at the site include the administrator, a branch manager, a guest, a loan officer, and a teller. Each of the desktops is inherited from the parent site as shown by the “[Inherited]” value for the desktop field. The administrator, branch manager, and loan officer desktops are inherited from “BranchA” site, while the guest and teller desktops are inherited from the “root” site. In this manner, self-contained desktops can be selected from a variety of parent sites or can be specifically configured for the child site. 
   When the new site data has been entered, the administrator selects “Create Site” command button  1190  to create the new site. If the administrator makes mistakes and wishes to reset the values, the administrator can select “Reset Values” command button  1195 . 
     FIG. 12  is a screen layout of a screen used by an administrator to manage desktops and machines for a given site. The administrator uses screen layout  1200  to manage desktops for a given site as well as to add and manage workstations that correspond to the site. The top half of screen layout  1200  is similar to the new site layout shown in  FIG. 11 . List box  1205  is used to select the parent site to assign to the site. The parent site can be changed to accommodate changes within the organization. Policy frame  1210  include the name of the policy  1212 , the policy value  1214 , and inheritance data  1216 . The inheritance data includes inheritance value  1218  and ancestor value  1220 . In the example shown, the policy name is “newbDC” which is inherited from the “root” ancestor. 
   Desktop frame  1225  includes role data  1230 , desktop data  1235 , and desktop inheritance data  1240 . In the banking example that is shown in  FIG. 12 , the roles included for the site consist of an administrator, a branch manager, the guest, a loan officer, and a teller. The desktop to be used by the administrator, branch manager, guest, loan officer, and teller. Each of these roles is shown in desktop data  1235 . Some of the values are inherited from a parent site while others are specified to be a particular self-contained desktop. Desktop inheritance data includes desktop inheritance  1242  and ancestor data  1244 . In the example shown, the administrator, branch manager, and loan officer each inherit desktop data from “BranchA”, while the guest and teller each inherit desktop data from the “root” parent. 
   If the administrator changes the site data and wishes to store the changed site information, the administrator selects “Submit Changes” command button  1245 . If the administrator wishes to reset the site values, the administrator selects “Reset Values” command button  1250 . If the administrator wishes to delete the site, the administrator selects “Delete Site” command button  1255 . 
   When the administrator is ready to publish the site to the servers, the administrator selects “Publish” command button  1260 . If the administrator wishes to publish the site along with any sites that are children of the site, the administrator selects “Publish with Children” command button  1265 . 
   Child sites frame  1270  includes data regarding any sites that are children of the site. Child site data includes site name  1272  and site policies  1278 . To create a new child site, the administrator can select “&lt;New Site&gt;” hyperlink  1275  which will allow the administrator to identify a new child site. 
   Machines frame  1280  includes data about workstations included at the site. Workstation data includes the workstation identifier  1282 , the host name for the workstation  1284 , the workstation type  1286 , the roles provided by the workstation  1288 , the workstation&#39;s IP address  1290 , and the workstation description  1292 . To add a new machine (workstation) to the site the administrator selects “&lt;New machine&gt;” hyperlink  1295 . 
     FIG. 13  is a screen layout of a screen used by an administrator to set up a new user (see  FIG. 5  for a corresponding flowchart). Screen layout  1300  includes text box  1305  for entering the new user&#39;s unique identifier. The user&#39;s full name is entered in text box  1310 . In addition, the description of the user can be entered in text box  1315 . For example, a user ID may be set up as a generic identifier such as a guest or teller that can be used by someone without having to establish a new user identifier for such infrequent or part-time users. The user identifiers used for such generic purposes can be further described using description text box field  1315 . 
   A new initial password is entered for the user in text box  1320 . This new initial password is confirmed by the administrator by reentering the password in text box  1325 . A default locale is selected by the administrator for the user using list box  1330 . In the example shown, the locale has been selected to be a U.S. locale for a user speaking U.S. English. However, if the user&#39;s primary language was Spanish or some other language, the appropriate locale is selected from the list provided in list box  1330 . 
   Frame  1332  is used by the administrator to select the roles that correspond to the user. Default role  1335  includes a number of radio buttons corresponding to each of the available roles. Radio buttons are used so that the administrator only selects one default role for the user. Select column  1340  includes a number of checkboxes corresponding to each of the available roles. The administrator selects each of the checkboxes corresponding to each role that is performed by the user. Name column  1345  includes the name of each of the available roles. In the example shown, the available roles include an administrator, branch manager, the guest, a loan officer, and a teller. The administrator can select one or more of these roles by selecting the corresponding checkboxes in column  1340 . In addition, the administrator can establish a new role by selecting “&lt;New Role&gt;” hyperlink  1350 . 
   When the administrator is finished entering the user data and assigning roles to the user, the administrator selects “Create User” command box  1355  to create and store the user data and assigned roles. If the administrator makes mistakes and wishes to reset the values, “Reset Values” command button  1360  is selected. 
     FIG. 14  is a screen layout of a screen used by an administrator to set up an application that is available as a component within one or more self-contained desktops (see  FIG. 7  for a corresponding flowchart). Screen layout  1400  is used to define a new application that can be included in self-contained desktops. Application identifier text box  1405  is used by the administrator to enter a unique application identifier that corresponds to the application that is being defined. In the example shown in  FIG. 14 , the type of application being defined is a “native” application, in other words an application wherein at least some of the application&#39;s executables reside on the client workstation. 
   A description of the application that is being defined is entered in description text box  1410 . Icon attributes frame  1415  is used to define the attributes corresponding to the icon that will appear on the desktop and be used by the user to select the application. Icon attributes include a title that is entered in text box  1420  and an icon filename that is entered in text box  1425 . 
   Platform properties frame  1430  includes data for each of the supported operating system platforms from which the application can be invoked. Win32 frame  1435  includes data which is used to invoke and execute the application from a Microsoft Windows operating system platform. The Win32 data includes a path and filename identifying the executable form of the application in the Win32 environment. The path and filename is entered in text box  1440 . Any parameters that are needed for the application are supplied in parameters text box  1445 . A working directory that corresponds to the application, if needed, is entered in text box  1455 . 
   Platform properties frame  1430  also includes data for the OS/2 operating system platform, the fields for which are located in frame  1460 . The OS/2 fields correspond to the Win32 fields described above. These include path and filename text box  1465 , parameters text box  1470 , and working directory text box  1475 . Likewise, a Linux set of fields is provided in frame  1480  which includes path and filename text box  1482 , parameters text box  1484 , and working directory text box  1486 . 
   When the application information has been entered by the administrator, the administrator can create the application by selecting “Create Application” command button  1490 . If the administrator makes mistakes, a new application values can be reset by selecting “Reset Values” command button  1495 . 
     FIG. 15  is a screen layout of a screen used by an administrator to set up a self-contained desktop. Screen layout  1500  includes various fields used to define the appearance and functionality of a self-contained desktop. The desktop identifier, which was previously defined, is displayed on the screen. In the example shown, the desktop identifier is “bda-administrator.” The title for the self-contained desktop is entered by the administrator in text box  1505 . In the example shown, the title is “Administrator.” A description for the self-contained desktop is entered in text box  1510 . In the example shown, the description entered is “Desktop for BDA Admins.” 
   A launch mode for the self-contained desktop is selected by the administrator using list box  1515 . The launch mode indicates the number of mouse clicks needed to activate a component from the desktop. In the example shown, the launch mode selected is “2” (i.e., a double-click). Icon attributes are entered in frame  1520 . Maximum allowable and displayable icon title lengths are entered by the administrator in the appropriate text boxes. 
   Background appearance information is entered by the administrator in frame  1525 . The color, image file, and image display mode are provided by the administrator for the background of the self-contained desktop. For example, desktop background data can include the name and logo of the organization. Icon appearance information is entered by the administrator in frame  1530 . Icon appearance data includes the text color of the icon, the font that is used with the icon, the font size that is used with the icon, the font style that is used to the icon, the icon flow, the origination point of the icon flow, and the text position for the icon text. 
   When the administrator has completed setting up the self-contained desktop, the administrator selects “Submit Changes” command button  1540  to save the desktop settings. If the administrator makes mistakes or wishes to reset the values, the administrator selects “Reset Values” command button  1545 . If the administrator wishes to delete the self-contained desktop definition, the administrator selects “Delete Desktop” command button  1550 . 
   Hyperlink  1560  is used to add, modify, or delete references that are available from the self-contained desktop. The references that are available include applications  1570 , folders  1580 , and toolbars  1590 . In the example shown, the applications that had been included consist of “acroread,” “calculator,” and “browser.” The folders that are included consist of an applications folder, and two administrator folders. One toolbar, the Admin Toolbar, is also included. 
     FIG. 16  is a screen layout of a screen used by an administrator to manage workstations (see  FIG. 6  for a corresponding flowchart). Screen layout  1600  is used by the administrator to manage the workstations, or computer systems, used throughout the network. Data maintained for each of the workstations includes the workstation identifier which is listed in column  1610 , the site to which the workstation belongs which is listed in column  1620 , the host (or server) assigned to the workstation which is listed in column  1630 , the types of functions performed by the workstation which are listed in column  1640 , the roles that the workstation is allowed to perform which are listed in column  1650 , the workstation&#39;s IP address which is listed in column  1660 , and a description for the workstation which is listed in column  1670 . 
   The identifiers shown in column  1610  are unique for each workstation. In the example shown in  FIG. 16 , the identifiers are the MAC addresses that correspond to the workstations. The sites shown in  FIG. 16  are either the “root” site, branch “A”, or branch “B.” These sites may represent physical or logical regions within the organization. The host name is the name of the server used by the workstation. The types of functions performed by the workstation include administration functions, server functions, and client functions. Types ending with “A” are used for administration functions, types ending with “S” are used for server functions, and types ending with “C” are used for client functions. As can be seen in  FIG. 16 , some workstations perform multiple types of functions. For example, the first workstation listed serves both administrator and server functions. Roles indicate the functions allowed to be performed on the workstation. Roles typically relate to client functions, so therefore workstations that do not have a client type do not have roles assigned. Workstations that have assigned roles often have multiple roles. For example, the third workstation listed has four roles that are allowed to be performed on the workstation (teller, loan-officer, branch manager, and guest). However, the fourth and fifth workstation shown only have one role that is allowed to be performed on each workstation. The IP address is the network address that is assigned to the workstation. In some environments the IP address is a static address, while in other environments the IP address is dynamically assigned. The description of each workstation is optional, yet helps the administrator better identify particular workstations and the roles such workstations play. 
     FIG. 17  is a flowchart showing steps taken to distribute self-contained desktops to servers. Administrator desktop distribution processing commences at  1700  whereupon the first desktop for distribution is selected (step  1705 ). A request is created with the desktop name and a unique signature, such as a CRC value (step  1710 ). The created desktop request is sent to one or more servers (step  1715 ). A determination is made as to whether there are more desktops to distribute (decision  1720 ). If there are more desktops to distribute, decision  1720  branches to “yes” branch  1722  whereupon processing selects the next desktop for distribution (step  1725 ) and loops back to create the request and send the request to the servers. This looping continues until there are no more desktops to distribute, at which point decision  1720  branches to “no” branch  1728 . 
   Server responses resulting from the previously sent desktop request are received by the administrator (step  1730 ). A determination is made based upon the response as to whether the desktop already exists at the server (decision  1735 ). If the desktop does not yet exist at the server, decision  1735  branches to “no” branch  1738  whereupon the identified desktop is sent to the server in a data stream (step  1740 ). On the other hand, if the desktop already exists at the server decision  1735  branches to “yes” branch  1742  bypassing step  1740 . 
   A determination is made as to whether there are more responses to receive from servers regarding the desktop request (decision  1745 ). If there are more responses, decision  1745  branches to “yes” branch  1746  to loop back and process the responses. This looping continues until there are no more responses to process, at which time decision  1745  branches to “no” branch  1748  and administrator desktop distribution processing ends at  1750 . 
   Server desktop collection processing commences at  1755  whereupon the server receives the desktop distribution request sent by the administrator (step  1760 ). The unique identifier for the desktop included in the administrator&#39;s request is compared with desktop data  1768  that is currently on hand at the server (step  1765 ). A determination is made based upon the comparison as to whether the desktop is needed by the server (decision  1770 ). If the desktop is not needed (i.e. the desktop already exists at the server) decision  1770  branches to “no” branch  1772  whereupon a message is sent to the administrator indicating that the server already has the desktop (step  1775 ) and server processing ends at  1795 . 
   On the other hand, if the server does not yet have the desktop decision  1770  branches to “yes” branch  1778  whereupon the server request the desktop (step  1780 ). The server receives the desktop data stream in response to the request (step  1785 ). The server then creates a self-contained desktop file from the received data stream and stores the desktop file in desktop data storage area  1768  (step  1790 ). Server desktop collection processing then ends at  1798 . 
     FIG. 18  is a flowchart showing steps taken to distribute self-contained desktops from a server to a client. Client desktop reception commences at  1800  whereupon the client sends a desktop list request to a server (step  1805 ). The desktop list request includes the client&#39;s machine (workstation) identifier and the client&#39;s user identifier. 
   Server desktop distribution processing commences at  1840  whereupon the server receives the desktop list request from the client (step  1845 ). The server looks up the roles that have been assigned to the user (step  1850 ) by searching user roles data store  1852 . The server also looks up the roles that have been assigned to the workstation being used by the user (step  1855 ) by searching machine roles data store  1858 . 
   The server retrieves desktop information based upon the intersection, or overlap, between the user roles and the machine roles (step  1860 ) and locates the desktops that correspond to the overlapping roles in desktop data store  1862 . The desktop information that is retrieved includes a desktop identifier and a desktop signature, such as a CRC, that is used to uniquely identify the desktop. A user may have a default role and a default desktop that corresponds that role. If the user has a default role, the server determines the default role (step  1865 ). 
   The server creates a response string (step  1870 ) of valid roles, desktop signatures, a default desktop identifier (if applicable), and a default role (if applicable). The server then returns the response string to the client (step  1875 ). 
   The client receives the desktop list that includes the roles that have been assigned to both the user and the workstation along with any default role and default desktop information from the server (step  1810 ). The client compares the desktops included in the desktop list with desktops that have already been cached on the client workstation (step  1815 ). This is done so that the client only needs to request those desktops that have not previously been transmitted to the client workstation and cached in the workstations volatile or nonvolatile storage areas. 
   The client determines whether additional components, or desktops, are needed from the server by identifying such desktops or components that have not yet been cached on the client workstation (decision  1820 ). If the client determines that no additional desktop components are needed, decision  1820  branches to “no” branch  1832  (bypassing the steps used to request and retrieve additional desktop information) and client processing ends at  1835 . 
   On the other hand, if the client needs additional components or desktops, decision  1820  branches to “yes” branch  1822  whereupon the needed desktops are requested from the server (step  1825 ). This request is received by the server at server step  1885 . The server responds by retrieving the request desktop information from desktop data store  1862  and returning it to the client workstation (step  1890 ). The server desktop distribution processing then ends at  1895 . 
   Returning to client processing, the client receives and caches the requested desktop information at step  1830  and client desktop reception processing ends at  1835 . 
     FIG. 19  is a flowchart showing steps taken to create custom application extensions. Custom application extensions allow a third party to extend a preexisting object oriented class to modify the behavior or attributes of a server class object to better serve the needs of a particular organization. Custom application extension creation processing commences at  1900  whereupon the client object oriented class is provided that implements a particular component interface (step  1910 ). A determination is made as to whether to extend the server abstract class (decision  1920 ). If the abstract class is not being extended, decision  1920  branches to “no” branch  1925  whereupon the default server component is used for the component interface (step  1930 ). On the other hand, if the abstract class is being extended, decision  1920  branches to “yes” branch  1935  whereupon the server class that extends the server component abstract class is provided (step  1940 ). 
   A determination is made as to whether additional resources are needed for the custom application extensions (decision  1950 ). If additional resources are needed, decision  1950  branches to “yes” branch  1955  whereupon the additional resources used by the application extension are provided (step  1960 ). The additional resources may include images, property files, and other class files used by the application extension. On the other hand, if additional resources are not needed decision  1950  branches to “no” branch  1965  bypassing step  1960 . 
   The client classes, server classes, and any additional resources are packaged in Java archive (JAR) files (step  1970 ). The packaged custom extensions are stored in custom extensions library  1980 . The creation of custom application extension process ends at  1995 . 
     FIG. 20  is a flowchart showing an application extension lifecycle. The application extension lifecycle begins at step  2000 . During the first phase of the application extension lifecycle, the application extension uses a no-arg constructor (step  2025 ). The no-arg constructor is used to create the application extension component by loading its Java implementation class and invoking a no-arg constructor. At this point, the application extension component has no reference to the client desktop and cannot interact with the desktop environment. During this phase, instance variables and default settings are initialized. 
   During the next phase of the application extension lifecycle, the application extension initializes (step  2050 ). During the initialization phase, the initialized method corresponding to the application extension is defined in the component interface. References to component configuration items, initial locale information, and desktop references are also provided. Desktop references are preferably saved as instance variables during this phase. 
   During the final phase of the application extension lifecycle, the start method corresponding to the application extension is invoked (step  2075 ). The start method is called by the desktop. For example the start method may be called when the icon corresponding to the application extension is selected by a user. During this phase, the application extension may use desktop references as well as references to other desktop components. In addition the application extension may at this time start threads and perform I/O operations. 
     FIG. 21A  is a block diagram showing components and resources being distributed from an administrator to multiple clients. Administrator  2100  publishes components and resource libraries  2105  that had been packaged into various desktop packages  2110  by transmitting these packages to various servers. 
   In the example shown in  FIG. 21A , there are three servers that receive desktop packages from the administrator. The servers include server  2120 , server  2140 , and server  2160 . Each of the servers includes a nonvolatile storage area for storing desktop packages receive from the administrator. Server  2120  uses nonvolatile storage area  2125  for storing desktop packages, server  2140  uses nonvolatile storage area  2145 , and server  2160  uses nonvolatile storage area  2165 . The desktop packages are distributed from the administrator to the servers in the process described in  FIG. 17 . The servers are used to provide desktop packages to various clients. 
   In the example shown in  FIG. 21A , there are two clients that receive desktop packages from each of the servers. Clients  2130  and  2135  receive desktops from server  2120 , clients  2150  and  2155  receive desktops from server  2140 , and clients  2170  and  2175  receive desktops from server  2160 . The desktops are distributed from the servers to clients using the process described in  FIG. 18 . In this manner, components and resources used in the various self-contained desktops are distributed from an administrator throughout the system to servers and eventually to clients. 
     FIG. 21B  is a block diagram showing components and resources being recovered by an administrator from servers following a data loss by the administrator. When a disaster event, such as a computer crash, fire, or flood occurs, the administrator may be left without the components and resources used to create the various self-contained desktops. In order to recover these files, administrator  2100  requests desktop packages, including the components that comprise the desktop packages, from the various servers. Using the topography described in  FIG. 21A , the administrator requests packages from servers  2120 ,  2140 , and  2160 . The servers retrieve self-contained desktop packages that include desktop components from storage areas  2125 ,  2145 , and  2165  respectively. The desktop information is transmitted from the various servers back to the administrator. The administrator stores the received self-contained desktop packages in restored package library  2180 . The components and resources that are included in the self-contained desktops are extracted from the desktop files and stored in restored components and resource libraries  2190 . In this manner, the administrator is able to recover and restore the components and resources that had previously been published to the various servers. This recovery is performed without having to have the administrator make separate backup copies of the components and resources. Because components and resources include unique identifiers, multiple versions, or levels, of components and resources are also able to be recovered. A flowchart showing the steps taken by the administrator to recover desktop data is shown in  FIG. 22 . 
     FIG. 22  is a flowchart showing steps taken by an administrator in distributing self-contained desktops and subsequently recovering self-contained desktops following a disaster event. Administrator processing commences at  2200  whereupon the administrator creates components and resources (step  2205 ) that will be used in self-contained desktops. These components and resources are stored in a library that is stored in nonvolatile storage area  2210 . 
   The components and resources are packaged (step  2215 ) into various self-contained desktops for use by various users based upon the users&#39; roles. The self-contained desktops are stored in self-contained desktop library  2225 . The self-contained desktops are distributed (step  2220 ) to various servers. Administrator distribution processing ends at  2230 . Further detail regarding the distribution of self-contained desktops can be found in  FIG. 17 . 
   Server reception of self-contained desktops commences at  2235  whereupon the server receives the self-contained desktop packages (step  2240 ) and stores the received packages in nonvolatile storage area  2245 . The server then distributes self-contained desktops to clients has needed (step  2250 ). Further detail regarding the distribution of self-contained desktops to clients can be found in  FIG. 18 . 
   At some point, a disaster event occurs destroying packages, resources, and components from the computer system and storage devices use by the administrator (step  2255 ). The self-contained desktop information is then recovered by the administrator using the recovery process commencing at step  2260 . The administrator identifies unique packages that have been destroyed and are no longer stored on the administrator&#39;s computer system (step  2265 ). The identified packages are requested from the various servers (step  2270 ). 
   The servers receive desktop package requests from the administrator (step  2275 ). The requested desktop packages are retrieve from the server&#39;s nonvolatile storage area  2245  and transmitted to the administrator&#39;s computer system (step  2280 ) and server recovery processing ends at  2295 . 
   The administrator computer systems receives the self-contained desktop packages sent by the servers and stores the received desktop packages in package library  2225  (step  2285 ). The self-contained desktop packages are unpacked and the components and resources that are included in self-contained desktop packages are used to repopulate components and resource libraries  2210  (step  2290 ). At this point, all packages, components, and resources that were previously distributed by the administrator have been recovered and stored in the appropriate libraries. Administrator recovery processing then ends at  2298 . 
     FIG. 23  is a flowchart showing steps taken by a client to receive and display desktops based upon the client&#39;s role (or roles) in the organization. Processing commences at  2300  whereupon the client machine receives the first desktop from server (step  2305 ). The received desktop is stored on client&#39;s local storage  2315 , either in a volatile or a nonvolatile storage area (step  2310 ). 
   A determination is made as to whether the received desktop is the default desktop for the client (decision  2320 ). If the receive desktop is the default desktop, decision  2320  branches to “yes” branch  2325  whereupon the received desktop is displayed on the client&#39;s display device (step  2330 ). On the other hand, if the received desktop is not the default desktop, decision  2320  branches to “no” branch  2335  bypassing step  2330 . 
   A determination is made as to whether there are more desktops for the client machine to receive from the server (decision  2340 ). If there are more desktops to receive, decision  2340  branches to “yes” branch  2345  whereupon processing loops back to receive the next desktop (step  2350 ) and determine whether the next desktop is the default desktop. This looping continues until all needed desktops have been received from the server, at which point decision  2340  branches to “no” branch  2355 . 
   A determination is made as to whether more than one desktop is accessible by the client (decision  2380 ). If more than one desktop is accessible, decision  2380  branches to “yes” branch  2385  whereupon the available desktop descriptions are inserted as items within a pop-up selection window that is accessible by the client (step  2390 ). For example, the user could “right” click in the desktop area using appointing device, such as a mouse, which would cause the pop-up menu to be displayed. The user could then select the desired desktop from the list provided in the pop-up menu (see  FIG. 27  for an example desktop screen and pop-up menu). For example, if a branch manager also has an assigned role of a loan officer, the branch manager can select the loan officer desktop from the pop-up menu. After selecting the loan officer desktop, the desktop components used for loan officer functions would be displayed and be accessible from the desktop area. On the other hand, if there are no more than one desktop accessible by the client, decision  2380  branches to “no” branch  2392  bypassing step  2390 . Display desktop processing then ends at  2395 . 
     FIG. 24  is a flowchart showing steps taken by a server to provide desktop information to a client based on the user&#39;s role and the workstation&#39;s role. Processing commences at  2400  whereupon the server receives a desktop request (step  2405 ) from client  2410 . The request includes the client&#39;s user ID, password, and the client workstation&#39;s MAC address. 
   The server looks up the client&#39;s MAC address (step  2415 ) from workstation table  2420  that includes the roles that are allowed to be performed on various workstations. In the example shown, the workstation with a MAC address of “123” is allowed to perform both teller and loan officer functions, while the workstation with a MAC address of “456” is only allowed to perform branch manager functions. 
   A determination is made as to whether the client&#39;s MAC address was found in the workstation table (decision  2425 ). If the MAC address was not found, decision  2425  branches to “no” branch  2428  whereupon a determination is made as to whether client workstation registration is required by the system (decision  2430 ). If workstation registration is required, decision  2430  branches to “yes” branch  2430  whereupon an error is returned to the client (step  2435 ) indicating that the client&#39;s workstation is not registered and server processing ends at  2440 . On the other hand, if workstation registration is not required decision  2430  branches to “no” branch  2442  and processing continues. Returning to decision  2425 , if the client&#39;s MAC address was found in the workstation table, decision  2425  branches to “yes” branch  2445  and processing continues. 
   The first desktop that has been assigned to the user&#39;s identifier (user ID) is retrieved (step  2450 ) from user desktop table  2455 . In the example shown, the user ID “Able” has been assigned to the “teller” role, while the user ID “Jones” has been assigned to the “teller,” “loan officer,” and “branch manager” roles. A determination is made as to whether the retrieved desktop assigned to the user is allowed to be used on the workstation that is being used by the user (decision  2460 ). If the desktop is allowed to be used to the workstation, decision  2460  branches to “yes” branch  2465  whereupon the desktop is sent to the client (step  2470 ). On the other hand, if the retrieved desktop is not allowed to be used on the workstation, decision  2460  branches to “no” branch  2472  bypassing step  2470 . 
   A determination is made as to whether there are more roles, or desktops, that have been assigned to the user (decision  2475 ). If there are more roles that have been assigned to the user, decision  2475  branches to “yes” branch  2480  whereupon the next desktop assigned to the user is selected (step  2485 ) and processing loops back to determine whether the next desktop should be set to client. This looping continues until all desktops assigned to the user have been processed, at which point decision  2475  branches to “no” branch  2490  and server processing ends at  2495 . 
     FIG. 25  is a block diagram showing processing performed by a server and interaction between the server, clients, and administrator. Server  2500  performs role identification function  2570  by receiving role assignments from administrator  2575 . Role assignments included roles that have been assigned to the user as well as roles that have been assigned to workstations located throughout the network. Workstation roles are stored in workstation role data store  2560 . The user roles are stored in user role data store  2555 . 
   Server  2500  also performs desktop collection processing  2580  by receiving desktop information from administrator  2575 . The desktop information is stored in desktop definition data store  2590 . The desktop information includes self-contained desktops that, in turn, included desktop components and resources for use by client  2525 . 
   Server  2500  receives authentication information from client  2525 , such as a user ID and password, which is used to authenticate the client. Server  2500  performs authentication processing  2510  by checking the client&#39;s authentication information with authentication data that is located in authentication data store  2520 . Once the client has been authenticated, the client receives access to client&#39;s data storage area  2540  which is stored on server  2500 . The server provides access to the client&#39;s data storage by performing home directory access process  2530 . In this manner, a user can access his or her data regardless of which workstation he or she is using. 
   Server  2500  performs desktop distribution process  2550  to determine which self-contained desktops to send to client  2525 . Desktop distribution process  2550  is performed by comparing user roles stored in user role data store  2555  with workstation roles stored in workstation role data store  2560 . Desktops, or roles, that are assigned to both the user and the workstation are distributed to the client. Server  2500  retrieves the desktop information from desktop data store  2590  and transmits the desktop information to client  2525 . 
     FIG. 26  is a flowchart showing steps taken by a client in initializing and displaying self-contained desktops. Client  2600  performs authentication request, home directory request, and password updates by sending the corresponding information to the server. Client  2600  uses an underlying operating system platform  2610  to perform native operations. JSLLIB  2680  is a native library that includes native commands and programs used to perform native operations. 
   Shell  2605  is a Java-based application that is adapted to run on any of the operating system platforms used in the system (e.g., Windows XP™, OS/2™, or Linux™). The shell makes a determination as to whether the client login is performed remotely through a server or locally (decision  2620 ). If the login is performed remotely, decision  2620  branches to “yes” branch  2622  whereupon the client receives desktops from the server (step  2625 ). In one embodiment, the desktops are received by first receiving a list of desktops and then retrieving individual desktops from the list. 
   The list, or map, of desktops is cached to local storage located on the client machine (step  2630 ). The received desktops are also cached to local storage (step  2635 ). Returning to decision  2620 , if the desktops are not retrieved remotely, decision  2620  branches to “no” branch  2638  bypassing steps  2625 ,  2630 , and  2635 . 
   The desktops that have been assigned to both the user and the workstation are retrieved from local storage (step  2640 ). Local storage is used to store user desktop map  2660  and desktops  2670 . Desktops are self-contained packages that include desktop components and resources needed to display and execute the desktop. The retrieved desktop information is used to create desktop objects (step  2645 ). Desktop class loader  2650  is used to create the desktop objects. Resources, such as national language translations, are loaded from the desktop information (step  2655 ). Desktop class loader  2650  is also used to load the needed resources. 
   At this point, the desktops assigned to the user in workstation have been retrieved and made available to the user within shell  2605 . Desktop objects and resources have been extracted from the self-contained desktops and have been made available to the user through shell  2605 . 
     FIG. 27  is a screen layout of a sample desktop displayed on a client workstation along with a pop-up menu of other self-contained desktops available to the client. Desktop screen layout  2700  includes a number of objects  2750 . Objects  2750  include desktop components that are accessible from the desktop. Each desktop component corresponds to a graphical image, such as an icon, which is selectable by the user using a pointing device such as a mouse. 
   Pop-up menu  2710  includes two items allowing the user to either change the desktop or display the shell version. Selecting the “Change Desktop” item causes the display of desktop selection menu  2720 . The user selects the desktop that is desired by placing a check mark in the box beside the desired desktop. In the example shown, the “administrator” desktop is being displayed on the client display as evidenced by the check mark shown in desktop selection menu  2720 . If the user wishes to change the desktop, for example to the branch manager desktop, the user simply uses a pointing device, such as a mouse, and places a check mark in the box next to the “branch manager” menu item. 
   Components  2750  may change depending upon the desktop that has been selected. For example, the “Branch Desktop Administrator” desktop component is displayed because the “Administrator” desktop has been selected. However, if another desktop, such as the “Teller” desktop, is selected, the “Branch Desktop Administrator” will no longer appear and will not be accessible from the display. In this manner, components for a selected role are displayed and accessible, while components used by a different role are not displayed and are not accessible. Moreover, components that are used by multiple roles are each available from the various desktops that correspond to the roles. 
     FIG. 28A  is a hierarchy chart of directories used by the client shell in displaying and managing desktops. Shell home directory  2800  includes a number of subdirectories used by the client for performing desktop functions. In one embodiment, the shell home directory and its subdirectories are stored on a server accessible by the client. In another embodiment, the shell home directory and its subdirectories are stored on a nonvolatile storage device local to the client machine. Native library  2805  is a subdirectory used to store programs used to interface with the client&#39;s operating system platform. In one embodiment, native library information is stored in Java archive (JAR) files. Properties subdirectory  2810  is a subdirectory used to store properties that are used by the shell program. These properties can include display attributes and other configuration items used by the shell program. 
   Desktop subdirectory  2815  is the directory in which self-contained desktop files are stored. In one embodiment, self-contained desktop files are packaged into Java archive (JAR) files. In this manner, all components and resources used by particular desktop are packaged and included in a self-contained desktop JAR file. Log subdirectory  2820  is used to store client-based logs that detail the actions taken by the client. “Conf” subdirectory  2825  is used to store initialization information used by the shell application. “Bin” subdirectory  2830  is used to store executables, such as program files, that are used to launch the shell application. 
     FIG. 28B  is a hierarchy chart of sections included with the shell configuration file. The shell configuration file includes number of sections. Each of these sections includes information about a particular aspect of the shell. In one embodiment, the shell configuration file is an XML file that includes a number of sections. The sections include locales section  2840  that includes information about the locale, such as national language translations, used by the shell application. Component section  2845  includes information about the components that are included with the self-contained desktop. Components include applications and other programs that are accessible from the desktop when the user selects an appropriate icon or other command. Folders section  2850  includes information about the various folders that are accessible from the desktop. Toolbars section  2855  includes information about the various toolbars that are displayed and accessible from the desktop. Desktop section  2860  includes information about the desktop, such as appearance data and policy information. 
     FIG. 28C  is a hierarchy chart of objects included in the self-contained desktop file. In one embodiment, the self-contained desktop is a Java archive (JAR) file. Self-contained desktop file  2865  includes number of components. The components include manifest  2870  which details the objects included in the self-contained desktop file. The components also include a Shell Document Type Definition (DTD) object  2875 . The Shell DTD object states what kinds of attributes are used to describe content in the Shell XML document, where each tag is allowed, and which tags can appear within other tags. Classes objects  2880  include the Java classes that are used by the desktop. Resources  2885  include resource information, such as national language translation information, that is used by the desktop. JAR objects  2890  include additional objects needed by the desktop that are packaged into further JAR files. XML object  2895  includes the XML document that is used to describe the self-contained desktop. 
     FIG. 29  is a flowchart showing steps taken to initialize the client&#39;s workstation to use self-contained desktops. Processing commences at  2900  whereupon user  2920  is prompted for a user ID and password (step  2910 ). The user ID and password are received from the user (step  2925 ). When authenticated, the virtual machine, such as a Java virtual machine (JVM), is loaded on the client operating system platform (step  2930 ) by JSL. The virtual machine is designed to execute platform-neutral code, such as Java applications. In this manner, the same desktops can be written in a platform independent language, such as Java, and executed on a variety of platforms that have implemented the needed virtual machine. 
   A Java-based lockdown shell is invoked (step  2940 ) to provide a desktop environment and prevent the user from accessing the underlying operating system being used by the client machine. Desktops that are assigned to both the workstation and the user are requested from a server (step  2945 ). Server  2950  receives requests and responds by sending self-contained desktops to the client. The client receives a response from the server (step  2955 ). The response may be an error or a list of desktops. 
   A determination is made as to whether an error was received from the server (decision  2960 ). If an error was received, decision  2960  branches to “yes” branch  2962  whereupon an error message is displayed on the client&#39;s display device (step  2965 ) and processing ends at  2995 . On the other hand, if an error was not receive, decision  2960  branches to “no” branch  2968  whereupon a determination is made as to whether there are any desktops to display on the client&#39;s display device (decision  2970 ). If there are no desktops display on the client&#39;s display device, decision  2970  branches to “yes” branch  2972 , the user is informed that there are no desktops to displayed (step  2975 ), and processing ends at  2995 . On the other hand, if there are desktops assigned to the user and the workstation, decision  2970  branches to “no” branch  2978  whereupon the desktops are displayed on the client&#39;s display device (predefined process  2980 ) and processing ends at  2995 . 
     FIG. 30  is a flowchart showing steps taken during client initialization. Processing commences at  3000  whereupon native login code is executed (step  3005 ). Login data is gathered from the user and sent to the server for processing (step  3010 ). The server sends a response back to the client which is received at step  3015 . 
   A determination is made as to whether the user was authenticated (decision  3020 ). If the user was not authenticated, decision  3020  branches to “no” branch  3025  whereupon processing ends at  3030 . On the other hand, if the user was authenticated, decision  3020  branches to “yes” branch  3035  to continue initialization. 
   The virtual machine application, such as a Java virtual machine, is invoked on the client workstation (step  3040 ). A lockdown process is launched in the Java environment in order to lock the shell and prevent the user from using the underlying operating system without using the shell environment (step  3045 ). The server is queried for the desktops have been assigned to the user/workstation (step  3050 ). The client receives a list of available desktops and compares the listed desktop information with desktop data that has already been cached on the client workstation (step  3060 ). Desktops that are included in list but not yet cached on the client workstation are retrieve from the server and cached on the client workstation (step  3070 ). The received desktops are stored in client accessible cache  3075 . An initial, or default, desktop is selected from the list of available desktops (step  3080 ). The components that comprise the default desktop are then displayed on the client display device with other available desktops made available to the user through a pop-up window (predefined process  3090 , see  FIG. 27  for example of a desktop display and  FIG. 9  for a flowchart showing details of creating desktops). Client initialization processing then ends at  3095 . 
     FIG. 31  is a flowchart showing steps taken during native operating system login. Native operating system login processing commences at  3100  whereupon a list of available network domains is displayed to the user (step  3110 ). A domain is selected from the list by the user (step  3120 ). A determination is made as to whether to authenticate the client locally or remotely (decision  3130 ). If the client is authenticated locally, decision  3130  branches to “yes” branch  3135  whereupon the user is authenticated at the local machine (step  3140 ). On the other hand, if the user is not authenticated locally, decision  3130  branches to “no” branch  3145  whereupon the user is authenticated on a server to which the client is connected (step  3150 ). 
   A determination is made as to whether the client was authenticated (decision  3160 ). If the user was not authenticated, decision  3160  branches to “no” branch  3165  whereupon an error is displayed on the client&#39;s display device (step  3170 ) and processing ends at  3195 . On the other hand, if the user was authenticated, decision  3160  branches to “yes” branch  3175  whereupon the Java shell launcher is invoked (predefined process  3180 , see  FIG. 32  for processing details) and processing ends at  3195 . 
     FIG. 32  is a flowchart showing steps taken when invoking the Java shell launcher. Java Shell Launcher execution commences at  3200  whereupon a class path, or directory, is set (step  3210 ). The Java virtual machine (JVM) is loaded on the client computing device (step  3220 ). 
   A determination is made as to whether the Jshell application is launched remotely or locally (decision  3230 ). If the Jshell application is launched locally, decision  3230  branches to “local” branch  3235  whereupon the Jshell application is launched with the user&#39;s user ID as a parameter (step  3240 ). On the other hand, if the Jshell application is launched remotely, decision  3230  branches to “remote” branch  3245  whereupon the Jshell application is launched remotely by providing the server hostname, the user ID, and the platform ID as parameters (step  3250 ). 
   After the Jshell application has been launched, JSL enumerates the OS window list to find the window corresponding to the Java shell (step  3260 ). The Java shell window is pinned to the bottom of the Z-order list of the operating system windows so that the Java shell window will always remain in the foreground (step  3270 ). The Java shell window is maximized to fit the display screen and all frame controls, such as minimize and resize buttons, are removed from the Java shell window (step  3280 ). In this manner, the shell application appears as the foreground page on the display and the user is prevented from using the shell page provided by the native operating system platform. Java shell launching processing ends at  3295 . 
     FIG. 33A  is a screen layout showing an example of a smart graphical component. The actual container type corresponds to an implementation construct such as a class in C++ and Java or a struct in C. This implementation construct will be referred to as the classtype. The smart component attempts to determine the classtype of it&#39;s parent component (e.g., a container) at runtime. If the identified classtype is of a type that the component recognizes, the component modifies its behavior and appearance according to the identified classtype. The behavior and appearance modifications can be programmatically incorporated into the smart component or read from a configuration file. If the classtype of the parent is not recognized, the component may be programmed to ascend it&#39;s parent hierarchy until a recognized container is found. In this manner, the component may be placed inside of a container with an unknown classtype, but if the parent container is itself inside of another container with a known classtype, then the component can configure itself as if it had been placed directly in the known container classtype. 
   The appearance and behavior of the smart component is determined by the classtype of it&#39;s parent container. For example, a smart icon will display a text description if it&#39;s parent classtype is a desktop. However, the same smart icon will not display the text description if it&#39;s parent classtype is a toolbar. Furthermore, the smart icons behavior may differ depending on the type of parent container. For example, if the icond is placed in a toolbar it may be programmed to draw a border around itself when the user places the mouse pointer over it. However, if the same icon is placed on the desktop it may be programmed to not display a border when the pointer passes over it. In addition, the smart icon may be programmed to execute different code related to the component upon activation depending upon the type of container to which it belongs. 
   Screen image  3300  includes two examples of a smart graphical component in the form of a time clock. Time clock  3305  is a component that has been placed in a toolbar container. Time clock  3330  is the same component, but this time the time clock has been placed in the desktop container. The appearance and behavior of the object changes depending upon the type of parent object, or container, to which the object belongs. In the example shown, time clock  3305  is displayed as a digital time because of the smaller area available in the parent toolbar container. Conversely, time clock  3330  displays an analog time because of the greater area available in the desktop container. In addition, time clock  3330  displays additional information such as the digital time and date underneath the analog clock image. Furthermore, time clock  3330  displays the name of the object (i.e. “clock”) underneath the object. 
   When the user selects time clock  3305  located in the toolbar, pop-up window  3320  is displayed. Pop-up window  3320  displays the day of the week, date, and has menu items to adjust the time/date and to set notifications. 
     FIG. 33B  is a screen layout showing an second example of a smart graphical component. Screen image  3350  is similar to a screen image shown in  FIG. 33A , however in  FIG. 33B  time clock  3330  has been selected and pop-up menu  3390  is displayed. The behavior of displayed pop-up menu shown in  FIG. 33B  is different from that shown for the same time clock component shown in  FIG. 33A . In particular, in  FIG. 33B  the user has display options as to whether a digital time clock, a day of the week, and display date should be shown along with the analog clock. These additional display options are available because of the larger size available for showing icons in the desktop container, rather than in a toolbar container. 
     FIG. 34  is a hierarchy chart showing various desktop objects. Desktop object  3400  is at the top of the hierarchy chart and includes component objects  3410  and container objects  3470 . Component objects  3410  include both visual components  3420  and non-visual components  3440 . Visual component objects include icons  3425 , folders  3430 , and toolbars  3435 . Non-visual component objects include application extension code  3445  and application definitions  3450 . 
   As the name implies, container objects  3470  include objects that can include, or hold, other objects. Container objects include folders  3480  and toolbars  3490 . Visual components such as icons can be included in container objects. 
     FIG. 35  is a flowchart showing steps taken in initializing smart graphical components. Smart graphical component initialization processing commences at  3500  whereupon a object oriented parent object is selected for component (step  3510 ). The object oriented class type for the selected parent object is retrieved (step  3520 ). A determination is made as to whether the retrieved class type is a recognized class type, such as a folder or a toolbar (decision  3525 ). If the retrieved class type is not recognized, decision  3525  branches to “no” branch  3545  whereupon a determination is made as to whether there are more parents in the object hierarchy (decision  3550 ). If there are more parents in the object hierarchy, the parent of the last selected object (i.e. the parent of the last parent, or the grandparent of the subject object) is selected (step  3560 ) and processing loops back to determine whether the newly selected parent is a recognized class type. This looping continues until either a recognized class type is found or there are no more parents in the object hierarchy. If a recognized class type is found, decision  3525  branches to “yes” branch  3530  whereupon the recognized class type is selected (step  3540 ). On the other hand, if there are no more parents in the object hierarchy, decision  3550  branches to “no” branch  3565  whereupon a default class type is selected for the object (step  3570 ). 
   Component appearance data, such as the icon size and other display characteristics, are retrieved along with object behavior characteristics that correspond to the selected class type (step  3575 ). For example, if the retrieved class type is a toolbar then the icon size and display characteristics would be based upon the smaller area available to an icon that is displayed in a toolbar. However, if the retrieved class type is the desktop then the icon size and display characteristics are based upon the larger area available in the desktop. 
   The component is displayed using the retrieved appearance data that corresponds to the class type. The system waits for the component to be invoked (step  3585 , i.e. until the component is selected by the user). When the component is invoked, the component is executed using behavior attributes that correspond to the class type (step  3590 ). 
     FIG. 36  is a flowchart showing steps taken in processing display attributes for smart graphical components. Smart desktop processing commences at  3600  whereupon a determination is made as to whether the class type is a toolbar (decision  3605 ). If the class type is a  20  toolbar, decision  3605  branches to “yes” branch  3610  whereupon the toolbar icon for the component is retrieved and displayed in the toolbar (step  3615 ), a border is drawn around the icon in the toolbar (step  3620 ), and processing ends at  3625 . 
   If the class type is not a toolbar, decision  3605  branches to “no” branch  3630  whereupon a determination is made as to whether the class type is a folder (decision  3635 ). If the class type is a folder, decision  3635  branches to “yes” branch  3640  whereupon the folder icon for  30  the component is retrieved and displayed in the folder (step  3645 ), a short component description is displayed underneath the icon (step  3650 ), and processing ends at  3655 . 
   If the class type is not a toolbar or a folder, decision  3635  branches to “no” branch  3660  whereupon a determination is made as to whether the class type is the desktop (decision  3665 ). If the class type is the desktop, decision  3665  branches to “yes” branch  3668  whereupon the larger icon is retrieved in displayed on the desktop (step  3670 ), a longer component description is displayed under the icon (decision  3675 ), and processing ends at  3680 . 
   If the class type is not a toolbar, a folder, or desktop, then decision  3665  branches to “no” branch  3682  whereupon a default icon is retrieved and displayed (step  3685 ), other default display characteristics are retrieved and applied to the icon (step  3690 ), and processing ends at  3695 . 
     FIG. 37  is a flowchart showing steps taken in processing behavior attributes for smart graphical components. Smart desktop processing commences at  3700  whereupon a determination is made as to whether the invoked component has a parent with a toolbar class type (decision  3705 ). If the invoked component has a toolbar parent class type, decision  3705  branches to “yes” branch  3710  whereupon the component&#39;s toolbar behavior is retrieved (step  3715 ), the retrieved toolbar behavior is executed (step  3720 ), and processing ends at  3725 . 
   If the invoked component does not have a parent with a toolbar class type, decision  3705  branches to “no” branch  3730  whereupon a determination is made as to whether the invoked component has a parent with a folder class type (decision  3735 ). If the invoked component has a folder parent class type, decision  3735  branches to “yes” branch  3740  whereupon the component&#39;s folder behavior is retrieved (step  3745 ), executed (step  3750 ), and processing ends at  3755 . 
   If the invoked component does not have any parent with a toolbar or folder class type, decision  3735  branches to “no” branch  3760  whereupon a determination is made as to whether the invoked component has a parent with a desktop class type (decision  3765 ). If the invoked component has a desktop parent class type, decision  3765  branches to “yes” branch  3768  whereupon the component&#39;s desktop behavior is retrieved (step  3770 ), executed (step  3775 ), and processing ends at step  3780 . 
   If the invoked component does not have a parent with a class type of toolbar, folder, or desktop, decision  3765  branches to “no” branch  3782  whereupon the components default behavior is retrieved (step  3785 ), executed (step  3790 ), and processing ends at step  3795 . 
     FIG. 38  illustrates information handling system  3801  which is a simplified example of a computer system capable of performing the operations described herein. Computer system  3801  includes processor  3800  which is coupled to host bus  3805 . A level two (L 2 ) cache memory  3810  is also coupled to the host bus  3805 . Host-to-PCI bridge  3815  is coupled to main memory  3820 , includes cache memory and main memory control functions, and provides bus control to handle transfers among PCI bus  3825 , processor  3800 , L 2  cache  3810 , main memory  3820 , and host bus  3805 . PCI bus  3825  provides an interface for a variety of devices including, for example, LAN card  3830 . PCI-to-ISA bridge  3835  provides bus control to handle transfers between PCI bus  3825  and ISA bus  3840 , universal serial bus (USB) functionality  3845 , IDE device functionality  3850 , power management functionality  3855 , and can include other functional elements not shown, such as a real-time clock (RTC), DMA control, interrupt support, and system management bus support. Peripheral devices and input/output (I/O) devices can be attached to various interfaces  3860  (e.g., parallel interface  3862 , serial interface  3864 , infrared (IR) interface  3866 , keyboard interface  3868 , mouse interface  3870 , fixed disk (HDD)  3872  coupled to ISA bus  3840 . Alternatively, many I/O devices can be accommodated by a super I/O controller (not shown) attached to ISA bus  3840 . 
   BIOS  3880  is coupled to ISA bus  3840 , and incorporates the necessary processor executable code for a variety of low-level system functions and system boot functions. BIOS  3880  can be stored in any computer readable medium, including magnetic storage media, optical storage media, flash memory, random access memory, read only memory, and communications media conveying signals encoding the instructions (e.g., signals from a network). In order to attach computer system  3801  to another computer system to copy files over a network, LAN card  3830  is coupled to PCI bus  3825  and to PCI-to-ISA bridge  3835 . Similarly, to connect computer system  3801  to an ISP to connect to the Internet using a telephone line connection, modem  3875  is connected to serial port  3864  and PCI-to-ISA Bridge  3835 . 
   While the computer system described in  FIG. 38  is capable of executing the invention described herein, this computer system is simply one example of a computer system. Those skilled in the art will appreciate that many other computer system designs are capable of performing the invention described herein. 
   One of the preferred implementations of the invention is an application, namely, a set of instructions (program code) in a code module which may, for example, be resident in the random access memory of the computer. Until required by the computer, the set of instructions may be stored in another computer memory, for example, on a hard disk drive, or in removable storage such as an optical disk (for eventual use in a CD ROM) or floppy disk (for eventual use in a floppy disk drive), or downloaded via the Internet or other computer network. Thus, the present invention may be implemented as a computer program product for use in a computer. In addition, although the various methods described are conveniently implemented in a general purpose computer selectively activated or reconfigured by software, one of ordinary skill in the art would also recognize that such methods may be carried out in hardware, in firmware, or in more specialized apparatus constructed to perform the required method steps. 
   While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention. Furthermore, it is to be understood that the invention is solely defined by the appended claims. It will be understood by those with skill in the art that if a specific number of an introduced claim element is intended, such intent will be explicitly recited in the claim, and in the absence of such recitation no such limitation is present. For a non-limiting example, as an aid to understanding, the following appended claims contain usage of the introductory phrases “at least one” and “one or more” to introduce claim elements. However, the use of such phrases should not be construed to imply that the introduction of a claim element by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an”; the same holds true for the use in the claims of definite articles.