Patent Publication Number: US-2012030296-A1

Title: Communications system providing reduced access latency and related methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Nos. 60/493,165, 60/493,167, 60/493,163 filed Aug. 7, 2003, and 60/494,235, 60/494,326, 60/494,255, and 60/494,234, filed Aug. 11, 2003 all of which are hereby incorporated herein in their entireties by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of communications systems, and, more particularly, to communications systems using multiple operating protocols for data access operations and related methods. 
     BACKGROUND OF THE INVENTION 
     Software clients operating on or in conjunction with a computer system are often used to access data stored at a server with which the computer system can establish communications, such as through a local area network (LAN). In many known systems, a server accesses a data system in response to a data access request received from a client. 
     However, the data system access time may cause errors for certain types of clients that time out if no response to a request is received within a predetermined response time. Delayed responses tend to be particularly problematic where communications between the client and server use communication channels or media having relatively high latency, such as wireless communication networks. 
     Various prior art approaches have been developed to address latency in data access requests. Once such approach is set forth in U.S. Pat. No. 5,802,292 to Mogul. This patent is directed to a method for predictive prefetching of objects over a computer network including client and server computer systems. The client requests a plurality of objects from the server, which are retrieved by the server and stored along with an identity of the client in a memory of the server. The server sends the plurality of objects from the memory to the client computer system over a network link. 
     The server also predicts a plurality of subsequent retrieval requests from the client computer system according to a predetermined criteria, and it sends the prediction to the client computer system. Prefetching of an object by the client may then be performed based on the prediction and other information. The patent states that with such an arrangement, an object may be prefetched before a user actually requests it, making the retrieval latency appear to be zero when a user requests a prefetched object. 
     Despite such prior art approaches, further techniques for reducing access latency are desirable in many applications, such as in wireless communications networks, for example. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing background, it is therefore an object of the present invention to provide a communications system providing enhanced operating protocol conversion features and reduced access latency and related methods. 
     This and other objects, features, and advantages in accordance with the present invention are provided by a communications system which may include a plurality of mobile wireless communications devices. Each wireless communications device may use at least one of a plurality of different operating protocols to send at least one access request. Moreover, the system may further include a plurality of data storage devices for storing data files. Each data file may be associated with a respective mobile wireless communications device and have a unique identification (UID) associated therewith. Each data storage device may also use at least one of the plurality of different operating protocols. 
     Moreover, the system may additionally include a protocol interface device including a protocol converter module for communicating with the plurality of mobile wireless communications devices using respective operating protocols thereof, and a protocol engine module for communicating with the plurality of data storage devices using respective operating protocols thereof. More particularly, the protocol engine module may also be for polling the data storage devices for UIDs of data files stored thereon, and for cooperating with the protocol converter to provide UIDs for respective data files to the mobile wireless communications devices upon receiving access requests therefrom. 
     Accordingly, the protocol interface device provides reduced latency after access requests, as the UIDs are readably available to be provided to the mobile wireless communications devices as soon as access requests are received. As such, this may result in a significant reduction in time-outs which may otherwise be experienced using operating protocols such as POP for wireless data access, for example. 
     The protocol engine module may also detect new data files stored on the data storage devices based upon UIDs thereof. For example, a memory may be coupled to the protocol engine module for storing UIDs from the most recent polling of the data storage devices. The protocol engine module may thus compare the stored UIDs with new UIDs returned at a next polling interval to detect new data files. Thus, the protocol engine module may advantageously cooperate with the protocol converter module to send alert notifications to respective mobile wireless communications devices upon detecting new data files therefor. The protocol engine module may also advantageously poll the data storage devices only for UIDs. 
     In addition, the protocol engine module may poll the data storage devices based upon a static polling interval, or based upon an adaptive polling interval. Also, the protocol converter module and the protocol engine module may communicate using a common interface protocol able to represent a desired number of protocol-supported elements for a desired operating protocol. By way of example, the common interface protocol may be based upon a Web-based distributed authoring and versioning (WebDAV) protocol. 
     Furthermore, the plurality of data storage devices, the plurality of wireless mobile communications devices, and the protocol interface device may process electronic mail (e-mail) messages, for example. Additionally, the communications system may further include a wide area network (WAN) connecting at least one of the wireless mobile communications devices with the protocol interface device, and/or connecting at least one of the data storage devices with the protocol interface device. 
     A method aspect of the invention is for interfacing a plurality of mobile wireless communications devices with a plurality of data storage devices, such as those discussed briefly above. The method may include providing a protocol converter module for communicating with the plurality of mobile wireless communications devices using respective operating protocols thereof. The method may also include providing a protocol engine module for communicating with the plurality of data storage devices using respective operating protocols thereof. More particularly, the protocol engine module may also be for polling the data storage devices for UIDs of data files stored thereon, and for cooperating with the protocol converter to provide UIDs for respective data files to the mobile wireless communications devices upon receiving access requests therefrom. 
     A protocol interface device in accordance with the present invention is for interfacing a plurality of mobile wireless communications devices with a plurality of data storage devices, and it may include a protocol converter module and protocol engine module such as those described briefly above. Moreover, a computer-readable medium in accordance with the invention may similarly include a protocol converter module and protocol engine module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram of a communications system in accordance with the present invention. 
         FIG. 2  is a schematic block diagram illustrating the protocol interface device of the communications system of  FIG. 1  in greater detail. 
         FIG. 3  is a schematic block diagram illustrating the extensible front-end proxy module of the protocol interface device of  FIG. 2  in greater detail. 
         FIGS. 4 and 5  are schematic block diagrams illustrating an alternate embodiment of a communications system in accordance with the invention implementing an extensible proxy architecture similar to that of  FIG. 3 . 
         FIG. 6  is a schematic block diagram of an alternate embodiment of the protocol interface device of  FIG. 2 . 
         FIG. 7  is a schematic block diagram further illustrating the protocol engine module of the protocol interface device of  FIG. 3  and interface connector modules therefor. 
         FIG. 8  is a schematic block diagram of an alternate embodiment of the protocol engine module and interface connector modules of  FIG. 7 . 
         FIG. 9  is a schematic block diagram of still another alternate embodiment of the protocol interface device of  FIG. 2 . 
         FIG. 10  is a schematic block diagram of yet another alternate embodiment of the protocol interface device of  FIG. 2 . 
         FIG. 11  is a flow diagram illustrating operation of the protocol interface device of  FIG. 2 . 
         FIG. 12  is a flow diagram illustrating operation of the front-end proxy module of  FIG. 3 . 
         FIG. 13  is a flow diagram illustrating operation of the communications system of  FIG. 5 . 
         FIG. 14  is a flow diagram illustrating operation of the protocol interface module of  FIG. 6 . 
         FIG. 15  is a flow diagram illustrating operation of the protocol engine and interface connector modules of  FIG. 7 . 
         FIG. 16  is a flow diagram illustrating operation of the protocol interface device of  FIG. 9 . 
         FIG. 17  is a flow diagram illustrating operation of the protocol interface device of  FIG. 10 . 
         FIG. 18  is a schematic block diagram of an exemplary mobile wireless communications device for use with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout, and prime notation and multiple prime notation are used to indicate similar elements in alternate embodiments. 
     Turning now to  FIG. 1 , a communications system  10  includes a protocol interface device  14  that provides access to a plurality of data storage devices or systems  16 ,  18 ,  20 . The communications system  10  illustratively includes a plurality of communications devices, namely a mobile wireless communications device  11  and a communications device  12  connected to the system via a wired connection. By way of example, various mobile wireless communications devices may be used in accordance with the invention, such as personal data assistants (PDAs), cellular telephones, etc. An exemplary mobile wireless communications device  11  suitable for use with the present invention is described in the example provided below with reference to  FIG. 18 . Moreover, examples of wired communications devices include personal computers, telephones, fax machines, etc. Of course, numerous wired and wireless devices may be used, although only two are shown in the exemplary embodiment for clarity of illustration. 
     The communications devices  11 ,  12  typically include software clients, which are software modules or applications that operate on or in conjunction with their respective communications device to provide access to data stored at one or more of the data storage devices  16 ,  18 , and  20  through the protocol interface device  14 . Those skilled in the art will appreciate that such communications devices also include further components and/or software modules, which have not been explicitly shown in  FIG. 1  for clarity of illustration. With respect to the mobile wireless communications device  11 , its software client communicates with the protocol interface device  14  via a wireless communication network  13 , and perhaps other networks as well (e.g., a public switched telephone network (PSTN) or the Internet), as will be appreciated by those skilled in the art. 
     The various functions and operations of the protocol interface device  14  are preferably implemented in software operating thereon, or in conjunction therewith. The protocol interface device  14  illustratively bridges the software clients of the communications devices  11 ,  12  and the data storage devices  16 ,  18 ,  20 . Communications between the protocol interface device  14 , the communications devices  11 ,  12 , and the data storage devices  16 ,  18 ,  20  are preferably via a wide area network (WAN) such as the Internet. That is, the communications devices  11 ,  12  may communicate with the protocol interface device  14  via the Internet, as noted above, and so too may the protocol interface device communicate with the data storage devices  16 ,  18 ,  20 . 
     Of course, other implementations are also contemplated. For example, the protocol interface device  14  may be implemented in a private network that also includes the data storage devices  16 ,  18 ,  20 , the communications devices  11 ,  12 , or both the data storage devices and the communications devices (e.g., in a WAN). It should be noted that the present invention is in no way limited to any particular connection or communication scheme. 
     The data storage devices  16 ,  18 ,  20  store data to be accessed by the software clients of the communications devices  11 ,  12 . Although some software clients are configurable to directly access certain types of data storage devices, they are often data system specific or protocol specific, as described briefly above. More particularly, on constrained electronic devices such as the mobile wireless communication device  11 , processor power, memory resources, and communication channel characteristics may preclude the installation and operation of software clients having the same capabilities as those commonly used on desktop and laptop computer systems, for example. In addition, while the installation of multiple software clients for accessing data storage devices associated with different protocols is feasible for desktop and laptop computer systems, providing multiple-protocol support on such constrained devices may not be possible. 
     The data storage devices  16 ,  18 ,  20  are accessible using different operating protocols or access schemes. As such, the protocol interface device  14  accesses the data storage devices  16 ,  18 ,  20  via an operating protocol supported by respective data storage devices, and provides data to the communications device  11 ,  12  via a respective client-supported operating protocol. The protocol conversion functionality of the protocol interface device  14  provides a unified approach to support access to multiple types of data system. As described in further detail below, the protocol interface device  14  provides an “any-to-any” bridge between different protocols or access schemes. 
     The protocol interface device  14  is illustrated in further detail in  FIG. 2 . As noted above, the protocol interface device  14  bridges different types of communications devices with different types of data storage devices. In the illustrated embodiment, data storage devices  24 ,  26 ,  28  are systems/servers for storing electronic mail (e-mail). However, it should be noted that the present invention is not limited to mail system access. Each of the mail systems  24 ,  26 ,  28  supports a different operating protocol or access scheme. More particularly, the mail system  24  supports Outlook Web Access (OWA), the mail system  26  supports Microsoft Messaging Application Programming Interface (MAPI), and the mail system  28  supports a proprietary protocol, such as that used by America Online (AOL), for example. 
     The protocol interface system  14  illustratively includes a front-end proxy module  30 . The front-end proxy module illustratively includes proxy modules  34 ,  36 ,  38 ,  40  which respectively support the Wireless Application Protocol (WAP), the Post Office Protocol (POP), the Internet Message Access Protocol (IMAP), and the Hypertext Transfer Protocol (HTTP) for communication with clients. 
     The front-end proxy  30  also communicates with a protocol engine module  32 . The protocol engine module  32  translates OWA, MAPI, the proprietary protocol of the mail system  28  (and other protocols, if desired) into a format compatible with the front-end proxy module  30 . To this end, a respective interface connector module may  70 - 77  ( FIG. 7 ) be coupled to the protocol engine module  32  for each of the operating protocols used by the mail systems  24 ,  26 ,  28 , as will be discussed further below. In a preferred embodiment, the front-end proxy module  30  and the protocol engine module  32  are extensible or expandable to accommodate additional operating protocols as they become available, as will also be discussed further below. 
     In operation, a user accesses a mailbox on one of the mail systems  24 ,  26 ,  28  through client software on his communications device. For example, a WAP browser on a mobile wireless communication device communicates with the WAP proxy module  34  to access the mail system  24 . Access commands or instructions received by the WAP proxy  34  are converted into a format compatible with the protocol engine module  32 . Communications between the front-end proxy module  30  and the protocol engine module  32  are preferably achieved via a common interface protocol, which may be a proprietary protocol or an established public protocol. 
     The protocol engine module  32  then translates the access commands or instructions received from the front-end proxy module  30  into a protocol associated with the mail system to be accessed (e.g., OWA for the mail system  24 ). Data received from the mail system (e.g., e-mail messages, a list of new messages, calendar appointments, tasks, etc., depending on the particular mail system), the features that its access protocol supports, and the nature of the access command are translated into the common interface protocol and transferred to the front-end proxy. 
     The active proxy module (i.e., the WAP proxy module  34  in the present example) then formats the received data, or at least portions thereof, for the requesting client. Further commands from the client are also translated by the protocol interface device  14 . Access commands from other types of clients are similarly processed. It should be noted that several mail systems may be accessed in response to a single access command, where a user has enabled multiple mailbox access through the protocol interface device  14 . 
     The protocol interface device  14  thus allows clients using different operating protocols to access the mail systems  24 ,  26 ,  28 , which also use different operating protocols. Access commands such as move, delete, create, send, fetch, and view, for example, that are generated at a client affect the data stored at the mail systems  24 ,  26 ,  28  instead of copies of the data. Through the protocol interface device  14 , a client compatible with any one of the proxy modules  34 ,  36 ,  38 ,  40  is provided access to one or more of the mail systems  24 ,  26 ,  28 . The client itself advantageously need not support the access protocol or scheme associated with the mail system(s) to be accessed. 
     Since the mail system protocol and the client protocol need not be compatible, feature support between the protocols may be different. For example, a POP client does not support the same features as OWA. The interface protocol used between the protocol engine module  32  and the front-end proxy module  30  is preferably designed to be able to represent a desired number of protocol-supported elements or features for a desired operating protocol. More specifically, the common interface protocol is preferably able to represent all protocol-supported elements for the most “capable” protocol (OWA in the present example), to provide the broadest possible feature support. Further still, the common interface protocol may support a full feature set across all supported protocols, if desired. 
     By way of example, the common interface protocol may be a proprietary protocol based on the Web-based Distributed Authoring and Versioning (WebDAV) protocol. An example of an authentication request using such a common interface protocol is provided as program listing #1, below. This exemplary authentication request routine allows the protocol interface device  14  to be authenticated by a mail system using a user identifier and password provided by a user, and it also retrieves a root folder and basic capabilities of a target mailbox on the mail system. 
     An exemplary inbox request in accordance with a WebDAV-based common interface protocol is set forth below as program listing #2. In accordance with this routine, responsive to an inbox request, the capabilities of the inbox in a target mailbox are queried, and then its contents are queried. Another example is provided below as program listing #3, which is for a folder search request in accordance with the aforementioned WebDAV-based common interface protocol. Here, a list of subfolders for a given folder is returned in response to this request. It will be appreciated by those skilled in the art that numerous other requests and operations may be used as well. 
     It should be noted that the software clients need not initiate data access requests in all embodiments. For example, in some embodiments the protocol interface device  14  may include (or communicate with) a polling or aggregation engine module (not shown) that prompts the protocol engine module  32  to aggregate messages for respective users from the mail systems  24 ,  26 ,  28  at predetermined intervals, as will be appreciated by those skilled in the art. The protocol engine module  14  would then cooperate with the front-end proxy module  30  to provide the aggregated messages to the respective software clients, as described above. Additionally, the front-end proxy module  30  need not communicate directly with the communications devices  11 ,  12  in all embodiments, but it may instead communicate therewith via an intervening mail system or server, for example. Thus, in the case where an aggregation engine module is used, the aggregated messages may be first transferred by the front-end proxy module  30  to an intervening mail server, which in turn provides the messages to the appropriate communications device, as will also be appreciated by those skilled in the art. Here again, the front-end proxy module  30  would use the appropriate protocol(s) supported by such intervening mail server for communicating therewith. 
     A method for providing access to a plurality of data storage devices, such as the mail systems  24 ,  26 ,  28 , using the protocol interface system  14  is illustrated in  FIG. 11 . Beginning at Block  110 , an access command or data is first received, at Block  111 . The access command or data is translated into the common interface protocol, at Block  112 . An access command is then translated (Block  113 ) into a data system protocol associated with the data system to be accessed, such as OWA for the mail system  24 , for example. 
     On the other hand, data is translated into the client protocol, at Block  113 . Depending upon the particular features supported by the client protocol, only those portions of the data corresponding to elements of the interface protocol that are supported by the client protocol are translated during this step. The protocol interface device  14  may generate an error responsive to a non-supported operating protocol. More particularly, non-supported interface protocol elements are preferably ignored or processed according to a default or error-processing scheme. Translated access commands or data are then transferred to a data system or a client, at Block  114 , thus concluding the illustrated method (Block  115 ). 
     Turning now additionally to  FIG. 3 , an exemplary embodiment of the front-end proxy module  30  is now described. The front-end proxy module  30  illustratively includes the proxy modules  34 ,  36 ,  38 ,  40 , a renderer module  44 , an extensible stylesheet language transformations (XSLT) engine module  46 , a memory or template store  48 , a flow controller module  50 , and handlers  52   a - 52   n.    
     As noted above, each proxy module  34 ,  36 ,  38 ,  40  effectively “fronts” the protocol engine module  32  and translates respective operating protocols for different client types. For example, a WAP proxy module provides information retrieved from one or more of the handlers  52   a - 52   n  in the form of WML documents targeted for display on devices such as cell phones and PDAs. A POP proxy makes use of at least some of the same proxy components, including the flow controller module  50  and the renderer module  44  to render data in the form required by the POP protocol. 
     One particularly advantageous benefit of the illustrated front-end proxy module  30  is that each proxy module  34 ,  36 ,  38 ,  40  makes use of the same core services to route traffic, access data, and render data. In other words, the renderer module  44 , XSLT engine module  46 , template memory  48 , flow controller module  50 , and handlers  52   a - 52   n  provide a common core service module for the proxy modules  34 ,  36 ,  38 ,  40 . The only differences between translations by the different proxy modules  34 ,  36 ,  38 ,  40  would be in the configuration of the flow controller  50 , the handlers  52   a - 52   n , and the XSL templates used to translate the data into its final form. It many cases, the same handlers  52   a - 52   n  will be re-used between by the various proxy modules  34 ,  36 ,  38 ,  40 , as will be appreciated by those skilled in the art. 
     During operation, a data access request from a client is passed to the appropriate proxy module  34 ,  36 ,  38 ,  40  using standard mechanisms for the client protocol. For a WAP client, for example, parameters are passed via a query string and/or form variables. The WAP proxy module  34  determines a component identifier (which identifies a target item such as a mail folder), an action identifier (which identifies an action to be performed), and any parameters based on data in the request. In the case of WAP, the component and action identifiers are passed in the query string or form. Other parameters in the query string or form are packaged into a parameter list. 
     The active proxy module then calls the flow controller  50 , passing along the identifiers and parameter list. The flow controller looks up the appropriate handler via the component and action identifiers and constructs the handler, passing the parameters as arguments to a constructor (not shown). Using the handler  52   a  as an example, this handler would processes the request, using a data layer ( FIG. 5 ) to gather information needed for a response. 
     For mail system access, for instance, the data layer communicates with the protocol engine module  32  for any information related to the contents of the user&#39;s mailbox, calendar, or address book, for example. Communications with other components may be established for different types of information, such as information related to authentication services and a user&#39;s e-mail account. The handler  52   a  then decides whether the request should be forwarded to another handler, or if its results should be rendered. 
     All information passed back by the handlers  52   a - 52   n  is preferably in a common format, such as org.xml.sax.InputSource, for example, a provider of extensible mark-up language (XML) data. The active proxy module then calls the renderer module  44 , passing along the InputSource, locale information, the name of the template to be rendered, and an OutputStream. The renderer module  44 , making use of the XSLT engine  46 , renders the page into the OutputStream. The OutputStream is then provided to the client by the active proxy module using the client protocol. 
     The above system provides a generic application framework following the classic model/view/controller (MVC) architecture that implements most of the application infrastructure. One important feature is that a base set of functionality may be defined for similar services and then extended to provide the service-specific functionality required to fully implement a given service. Within a given implementation, the flow controller  50 , the handlers  52   a - 52   n , and/or the data access layer are fully extensible or replaceable. 
     With this in mind, supporting a brand new service simply involves defining and implementing the data layer, defining the control flow and discrete actions within the system (i.e., the flow controller module  50 ), and defining and implementing the interface with the service (i.e., the renderer module  44 ). On the other hand, supporting a new type of client with an existing service involves making minor changes to, and extending actions within, the flow controller module  50  and handlers  52   a - 52   n  to support additional client-required functionality, and defining and implementing the interface between the client and the system (i.e., the renderer module  44 ). 
     Operation of the front-end proxy module  30  to perform protocol translation is further described with respect to the block diagram of  FIG. 12 . Certain of the illustrated operations have been described in detail above, and thus will be described only briefly below to avoid undue repetition. Beginning at Block  120 , an access request or command is received at a proxy module  34 ,  36 ,  38 ,  40 , at Block  121 . The access request is translated into the common interface protocol by one or more of the handlers  52   a - 52   n , at Block  122 . 
     Data is received from a given mail system  24 ,  26 ,  28  in response to the request, at Block  123 . This data, which has already been translated into the common interface protocol by the protocol engine module  32 , is rendered (Block  124 ) and returned to the client, at Block  125 , thus concluding the illustrated method (Block  126 ). Depending upon the particular features supported by the client protocol, only portions of the data corresponding to elements of the common interface protocol that are supported by the client protocol are rendered or translated. Non-supported interface protocol elements may be ignored or processed according to a default or error processing scheme, as noted above. 
     It should be noted that the extensible, common core service architecture of the front-end proxy module  30  may also be used for a variety of applications. One such application is to address various shortcomings of the disparate methods used to respond to HTTP requests from a Web application. Referring now to  FIGS. 4 and 5 , a Web data access system  100  having an extensible architecture in accordance with the present invention is now described. The components of the Web data access system  100  communicate bi-directionally, and they illustratively include a user request  101 , a Web server  102 , a proxy server  104 , and an extensible controller system  106 . 
     More particularly, the user request  101  refers to a user using a web browser or web application to request a web page (e.g., from a PDA or personal computer). Once the request is made, the Web server  102  processes the request. The proxy server  104  assists the Web server  102  in processing the request. For comparison purposes, the proxy server  104  here functions similar to the protocol interface device  14  discussed above, and the extensible controller system  106  would be implemented as a software module that is run on or in conjunction with the proxy server, as will be appreciated by those skilled in the art. Of course, in some embodiments the proxy server  104  and extensible controller system  106  could be implemented in different physical devices or servers, for example. 
     The proxy server  104  provides a process of providing cached or storage items available on other servers which are slower or more resource intensive to access. The proxy server  104  accepts URLs with a special prefix. When it receives a request for such a URL, it strips off the prefix and looks for the resulting URL in its local cache. If found, it returns the document immediately, otherwise it fetches it from the remote server, saves a copy in the cache, and returns it to the requester. The pages returned by the proxy server  104  can be either static or dynamic in nature. The proxy server  104  may communicate with application servers or data servers, and in this specific embodiment, the extensible controller system  106 . 
     More particularly, the components of the proxy server  104  illustratively include an aggregate server  202 , a renderer module  212 , an XSLT engine module  214 , and a memory  216  for storing a series of templates, similar to those described above. The components of the extensible controller system  106  include an action map  204 , and a series of handlers  206 , also similar to those discussed above. 
     The aggregate server  202  performs the processing of incoming information and passes it onto other components for assistance. The renderer module  212  renders the resultant data into a viewable format. The renderer module  212  makes use of the XSLT engine module  214  and any necessary templates from the memory  216  to render the page. 
     The aggregate server  202  sends data to the action map  204 , which maintains the control flow and handles the business logic in the system. The action map  204  interacts with a series of handlers  206 . The handler  206  utilizes the data layer  208  to retrieve information from other data sources  210 . The other data sources  210  may include, for example, XML for web data, a universal proxy for any information related to the contents of user applications (e.g., e-mail, calendar or contact), or a provisioning API for authentication services and data relating to a user account. 
     The system functions by having a user send in a URL as a user request  101 . This request is received at the Web server  102 , which passes on to the proxy server  104  for processing using standard mechanisms for the protocol. For example, a WML request would pass a WAP parameter query string and/or form variables. The aggregate server  202  component of the proxy server  104  determines the component ID, action ID and any parameters based on data in the request. Using the same WAP example, the component and action IDs are passed in the query string or form. All other parameters in the query string or form are packaged up into a parameter list. 
     The aggregate server  202  then calls the action map  204  of the extensible controller system  106  and passes along the IDs and parameter list. The action map  204  looks up the appropriate handler  206  via the component and action IDs and constructs the handler, passing the parameters as arguments to the constructor. The handler  206  processes the request, using the data layer  208  to gather information needed for a response. The data layer  208  will retrieve information from other data sources  210  located within the network or external to the network. The handler  206  then decides whether the request should be forwarded to another handler  206 , or if its results should be rendered. 
     If the system decides to render the data, the data is passed from the handler  206 , back to the action map  204 , and back to aggregate server  202  of the proxy server  104 . The aggregate server  202  then calls the renderer module  212 , which invokes the XSLT engine module  214  and any necessary templates to render the data into a viewable output. This output is then returned to the Web server  102  to serve the data as a viewable web page as a result of the user request  101 . 
     The various steps involved in processing Web data using the extensible controller system  106  will now be further described with reference to  FIG. 13 . More particularly, this diagram illustrates in greater detail the processing and interaction of the proxy server  104  and the extensible controller system  106 . The system flow begins with a user request  101 . This request is sent to the Web server  102 , which passes the information to the proxy server  104  for processing. The proxy server  104  invokes the aggregate server  202  for processing. 
     The aggregate server  202  determines whether a context is available, at Block  302 . If it is available, the system will move to the next step to mine the IDs (Block  306 ). If it is not available, the system will first create the context, at Block  304 , and then continue onto the step to mine the IDs, at Block  306 . The action ID and component ID are also mined out of the system. These IDs, along with the request parameters and any form data, are packaged into an envelope and gathered together, at Block  308 . 
     An invoke procedure is called to pass the data from the aggregate server  202  to the action map  204  of the extensible controller system  106 . This invoke procedure will pass information pertaining to the envelope, an action code, the component ID and context info to the action map  204 . The action map  204  looks up the action, at Block  310 , and determines whether the action exists, at Block  312 . If it does, then it moves to the next step to determine whether the action requires authentication, at Block  316 . If the action does not exist, the system retrieves the default action, at Block  314 , and then determines whether the action requires authentication, at Block  316 . 
     At this point, if the action does not require authentication, the system determines if any requests are pending, at Block  320 . If the action does require authentication, the system then determines whether the context is in an authenticated state, at Block  318 . If the context is in an authenticated state, the system then determines whether a request is pending, at Block  320 . However, if the context is not in an authenticated state, the system returns the request to the retrieve default action, at Block  314 , until authentication is accepted. 
     At Block  320 , the system determines if a request is pending. If a request is pending, the system executes on the pending request and jumps to next stage, determining whether a process is in queue, at Block  346 . If no request is pending, the system executes on the action and validates on the envelope data, at Block  322 , and passes control to the handler  206  to create the action handler, at Block  324 . Once the action handler is created, it is initialized, at Block  326 . 
     The system then determines whether background processing is allowed, at Block  328 . If so, a background handler is created, at Block  344 , and the system determines whether a process is in queue, at Block  346 . However, if background processing is not allowed, the system then processes the action handler, at Block  330 , and then returns the result, at Block  332 . Revisiting the system, at Block  346  the system determines whether a process is in the queue. If the process is in the queue, it then determines whether the action is complete, at Block  350 . If the process is not in the queue, then it submits it to the queue, at Block  348 , and then determines whether the action handler is complete, at Block  350 . 
     If the action handler is complete, the system returns the action handler result, at Block  352 . If the action handler is not complete, the system returns the pending render result, at Block  354 . The output of the steps illustrated at Blocks  352  and  354  (returning either an action handler result or pending renderer result) will be used to determine whether to render the result, at Block  334 . 
     More particularly, the results of the steps illustrated at Blocks  332  (return result),  352  (return action handler result) and  354  (return pending render result) are used to determine whether to render the result (Block  334 ). If the system decides to render the result, the system sends the data from the extensible controller system  106  to the proxy server  404  and renders the data, at Block  340 , at the renderer module  212 . The data is then passed onto the Web server  102  to display the result, at Block  342 , as a response to the user request  101 . However, if the system decides not to render the result and has instead decided to forward the request to another action handler for processing, the system retrieves the ID keys, at Block  336 , retrieves the envelope data, at Block  338 , and then looks up the appropriate action, at Block  310 . The system will loop around at this point until a decision to render a result is ultimately accepted, at Block  334 . 
     The above-described method involves using a single source for defining the components within the system. In this particular embodiment, the source is an XML file, but other formats could be used as well, as will be appreciated by those skilled in the art. This source would define the code that handles the request, the URL syntax and parameters, templates or code used to generate the response for the request, and the routing information for the request, for example. 
     The code that handles the request, along with the parameter definition, is used by the system to create the action handler, pass the correctly typed parameters, and pass control to it for processing. The parameters include type information allowing for strongly typed data. The parameters may also be defined as optional or required. The template or templates are used to generate the response for the request. If an attempt is made to generate a response other than to what was defined an error is generated. 
     The source would also define the routing information for the request. Often times, it is desirable for a handler to perform work within its scope and then hand off control to another handler to allow it to perform its work. However, if the handler attempts to hand control to something not defined in the source, an error is generated. 
     Other variations are also possible. For example, the source may be used whenever generating URL&#39;s for use within the system. Moreover, request routing may be separated from the actual processing of those requests. Control flow is then handled by one component of the system, not by each handler. The handler would then simply ask the controller to forward a request to another handler. Thus, incoming data may be kept in a known state for the life of a particular request. 
     Yet another approach involves enforcing control flow through the system where one handler does not call another handler directly to do its work. Still another approach involves keeping the handlers relatively small and simple. That is, this will limit the handler&#39;s purpose and scope to receiving requests and calling the appropriate business logic to gather the desired results. Another variation involves keeping each handler focused on one task, and upon completion of the task, allowing the results to be rendered or forwarded on to the next handler. 
     A further variation involves providing an extensible mechanism for handling requests that can handle immediate needs, as well as grow over time without becoming overly complex. When loading the system, the user is able to specify a primary and secondary action map. In this way, generic business logic and control flow may be specified by the primary action map while still providing the user with a method of adding or modifying the functionality. Another approach is to provide the developer with a generic mechanism for responding quickly to long running requests to avoid generating a timeout. This enables the developer to specify background processing at either a handler level, or at the entire system. 
     The above-described extensible controller is particularly advantageous for addressing shortcomings in Web or HTTP-based applications. Of course, it will be also appreciated by those skilled in the art that this same architecture may be extended to support other types of non-HTTP based applications as well. 
     Turning now to  FIG. 6 , an alternate embodiment of the protocol interface device  14 ′ is now described. In the illustrated embodiment, all requests to a data storage device, such as the mail systems  24 ′,  26 ′,  28 ′, are defined in configuration files stored in a configuration file store or memory  31 ′. In this way, for a given client category, an application developer can easily request only those properties required to support the client for which it was written. 
     A resource manager, which may be part of the front-end proxy module  30 ′ or a separate component of the protocol interface device  14 ′, advantageously allows a user to specify a primary and secondary set of configuration files. If a secondary configuration file is specified, any resources defined in it will override those specified in the primary configuration file. This allows the user to specify a core set of resources and then tweak them to fit a particular implementation. 
     Moreover, configuration files may be stored for processing operations at different network layers. For example, configuration files for data layer operations for interfacing the front-end proxy module  30 ′ and protocol engine module  32 ′ may be stored in the memory  31 ′, as well for upper network layer operations performed by the flow controller module  50 , for example. Other types of configurations files may be used as well, as will be appreciated by those skilled in the art. 
     A configuration file also preferably specifies the implementation class that is created to handle the response to a given request. This makes it a simple matter to slightly change the behavior of an object in a data model, or even completely replace it. Caching behavior and strength for each request may also be specified in a configuration file. With a combination of these two properties, a developer can have much greater control over memory consumption and response/request performance. 
     In addition, configuration files also allow a user to specify multiple requests for a given resource. This makes it possible to support data systems with different request/response formats. An exemplary configuration file is provided below as program listing #4. This configuration file is suitable for a data store that supports a WebDAV interface, as discussed above, or in the case of the protocol interface device  14 ′, a protocol engine that supports a WebDAV interface. However, it could be used for other types interfaces/data stores as well. 
     It should also be noted that, in addition to the content class specified for the resource, a user may also specify a command to further identify a given resource. This allows the user to perform multiple different operations on a given resource type, as will be appreciated by those skilled in the art. 
     Operation of the protocol interface device  14 ′ using configuration files will now be described further with reference to  FIG. 14 . Beginning at Block  140 , an access request or command is received at a proxy module, at Block  141 . The access request is translated into the common interface protocol by a handler  52   a - 52   n , at Block  142 , with reference to one or more configuration files. Data that is received from the data system (Block  143 ) in response to the request, and which has already been translated into the common interface protocol by the protocol engine module  32 ′, is formatted into a response and rendered, at Block  144 . Again, this is done with reference to one or more configuration files. The rendered response is then returned to the client (Block  145 ), thus concluding the illustrated methods, at Block  146 . 
     Referring now additionally to  FIG. 7 , the protocol engine module  32  will now be described in further detail. The protocol engine module  32  provides a framework to incorporate various interface connector modules  70 - 77  that communicate with various mail systems using different protocols. The protocol engine module  32  also provides a common interface XML and WebDAV, for example, that the clients, through the front-end proxy module  30 , use to access various mail accounts. Common operations like retrieving only the essential headers of new mail and determining the presence and size of attachments without downloading them are highly efficient. All operations are performed directly on the source, and only the essential data is retrieved. 
     The protocol engine module  32  uses an appropriate one of a plurality of interface connector modules  70 - 77  to access a mail account. All of the connector modules  70 - 77  preferably support a common application programming interface (API), such that adapting the protocol engine module  32  to support a new protocol amounts to simply adding a new interface connector module. The connector modules  70 - 77  may be written in Java, for example, although other suitable languages or protocols may also be used. Overall system performance and availability may be improved, for example, by providing multiple dynamically load-balanced protocol engine machines. 
     Results received by the protocol engine module  32  from the mail systems  24 ,  26 ,  28  are similarly translated into the common interface protocol for translation into a client-supported protocol, if necessary, and transmission to a client. The results communicated back to a client preferably include only data that was requested by the client. Data corresponding to features that are supported by a mail system protocol but not by a client protocol may be translated into the common interface protocol, but it may also be ignored or handled according to a default or error processing scheme, as noted above. 
     A method of protocol translation using the protocol engine module  32  and interface connector modules  71 - 77  is now described with reference to  FIG. 15 . Beginning at Block  150 , an access request or command is received, at Block  151 . The access request is translated into a protocol supported by the target data system, at Block  152 . Data is received from the data system in response to the request, at Block  153 , and it is translated into the common interface protocol, at Block  154 . Further translation of the data into a client protocol may be performed, if necessary, at Block  155 , and the data transmitted to the client at Block  156 , thus concluding the illustrated method, at Block  157 . 
     Again, depending upon the particular features supported by the client protocol, only portions of the data corresponding to elements of the common interface protocol that are supported by the client protocol are translated. As described above, non-supported interface protocol elements may be ignored or processed according to a default or error processing scheme. 
     Turning now to  FIG. 8 , an alternate embodiment of the above-described protocol conversion module architecture is now described. Here, the protocol engine module  32  takes the form of a universal proxy (UP) servlet module  80 , and each interface connector module  81 ,  82 ,  83  and a respective provider module  84 ,  85 ,  86  are associated with different operating protocols. In the illustrated example, the different protocols are OWA, IMAP, and POP. Further or different protocols may be supported by corresponding provider/connection pairs, as will be appreciated by those skilled in the art. 
     For a common interface protocol, such as the proprietary interface protocol described above, the UP servlet module  80  takes incoming common format requests and translates them into calls, using the defined interfaces, to the interface connector modules  81 - 83 . The UP servlet module  80  also takes the results of these calls and formats them into common format requests. Each common format request includes a method request and a path in the form of a URL. It may also include an XML document that provides additional parameters for the request. 
     Conceptually, below the UP servlet module  80  there is a provider module  84 - 86  for each supported mail system protocol. The providers take care of handling the calls made by the UP servlet module  80 . As shown, each provider has a connection, which takes care of communicating with the source mailbox/account on a target mail system. Initially, the connection will also be the provider. 
     The interfaces used by the UP servlet  80  and implemented by the provider modules  84 - 86  define a loose folder hierarchy. In fact, it may be conceptualized as a collection of collections of items. An item can be a message, a folder, or a contact, for example, or any other data item to be represented. Each item has a defined type (e.g., mail, contact, appointment). An interface for each type of item defines the properties and actions that are available for that type of item. A folder item includes a collection of items, and provides methods to enumerate the items within a folder. 
     The connector interface modules  81 - 83  provide a common way for the UP servlet module  80  to communicate with different provider modules/interface connector modules. Some connector modules may only implement a subset of the protocol and/or may only support a single folder (collection) of items, as in the case of POP. 
     The basic flow for an exemplary common format request proceeds as follows. The UP servlet module  80  receives the request, and it either retrieves or creates the appropriate provider/connection. The UP servlet module  80  then calls an appropriate “get folder” or similar function associated with the interface connector module, passing a target mail system identifier, such as a URL that was included in the common format request. The interface connection module returns a reference to some object that implements the folder interface and represents the requested folder. In its simplest implementation (e.g., POP), a single object could be the interface connector module and also represent the mailbox folder. 
     The UP servlet module  80  uses the returned folder reference to make additional calls to satisfy the common format request. For example, if the UP servlet module  80  needs to retrieve a specific item, it may first call a “get folder” function, passing the requested URL, and after it has the folder, it will then call a “get item” function, again passing the URL. The results of the call(s) are then formatted into an appropriate format, such as XML, and returned in an HTTP response. 
     It will be up to the provider module/interface connection module to interpret a URL passed in and return the appropriate reference. This will not be complicated because the provider module/interface connection module provides the URLs in the first place. The only URL that any interface connection module will be required to know about is “\”. All other URLs are generated by the provider/connection. As long as the URLs within the hierarchy/collections are unique, the provider will be able to resolve to the correct item when a “get” function is called. 
     The provider modules  84 - 86  and interface connection modules  81 - 83  preferably support a root folder. If only a root folder is supported, then inbox, calendar, and contact items (as appropriate) should be items within that folder if they are to be accessible through a protocol engine. 
     In accordance with one aspect of the invention, a single, advantageous mechanism to access various types of protocols is provided. This mechanism supports the full functionality of each data system protocol for similarly capable client protocols, and degrades when a specific data system protocol feature is not supported by a client protocol. Requests received in a common format are translated into a provider/protocol specific format before forwarding the request on to the destination server. Responses from the destination server, which are in provider/protocol specific format, are translated back into the common format. 
     A mechanism for a client to query supported functionality for a specific provider module, giving the client greater control over how it generates requests to the provider, is also provided. Any client written to support the common protocol format, directly or through a proxy, can easily provide access to any mail store without concerning itself with the details of the mail store provider module/protocol. 
     Referring now additionally to  FIG. 9 , another embodiment of the protocol interface device  14 ″ is now described. Here, user e-mail account information associated with e-mail accounts to be accessed through the protocol interface device  14 ″ is stored in a data store  90 ″. The per-account information preferably includes an indication of the access protocols supported for each e-mail account. 
     Records in the data store  90 ″ may be arranged by an account identifier, such as an e-mail address, or by a user name associated with the protocol interface device  14 ″ such that all e-mail account information for particular users is grouped in the data store  90 ″, for example. Where access protocol support is the same for all e-mail accounts on each of the mail systems  24 ″,  26 ″, the per-account information may include mail system information indicating the operating protocols supported by each mail system. 
     A data store  91 ″ stores a list of all operating protocols supported by the protocol engine module  32 ″, and corresponding metrics (i.e., ranking) representing protocol preferences. These metrics are calculated based on capability criteria, such as the degree to which features of each mail system  24 ″,  26 ″ are supported by a protocol and the security level of a protocol, for example. Other criteria may also be used and will be apparent to those skilled in the art. In the data store  91 ″, OWA would typically have a higher metric or ranking than MAPI, and IMAP would generally be ranked higher than POP. Each of the data stores  90 ″,  91 ″ may be implemented, for example, in a database on a local hard disk or other memory at the protocol interface device  14 ″, or on a file server with which the protocol interface device communicates. 
     The protocol engine module  32 ″ determines to which mailbox(es) or account(s) the command or instruction relates, and then accesses the per-account information in the data store  90 ″ to determine whether more than one access protocol is supported for each account to be accessed. If only one access protocol is supported, then that protocol is selected. Where more than one access protocol is supported for the account, then the protocol engine module  32 ″ accesses the data store  91 ″ to determine which supported protocol is preferred or desired, and the supported protocol with the highest metric or ranking is selected. For the mail system  24 ″, OWA is preferably selected over MAPI, and for the mail system  26 ″, IMAP is preferably selected over POP. 
     The protocol interface device  14 ″ thus allows access to the mail systems  24 ″,  26 ″ using a most capable supported protocol. Through the protocol interface device  14 ″, a client compatible with any of the proxy modules  34 ″,  36 ″,  38 ″,  40 ″ is provided access to one or more of the mail systems  24 ″,  26 ″. The client itself need not support the access protocol or scheme associated with the mail system(s) to be accessed. 
     A method of data system access protocol selection using the protocol interface device  14 ″ is now described with reference to  FIG. 9 . Beginning at Block  160 , an access command is received from a client at Block  161 . A determination is made (Block  162 ) as to whether each data system to be accessed in response to the command supports more than one access protocol. If so, then the most capable supported protocol is selected, at Block  164 . Otherwise, the one supported protocol is selected, at Block  163 . Each data system is accessed using the selected protocol, at Block  165 , thus concluding the illustrated method, at Block  166 . Where more than one data system is to be accessed, the protocol selection steps illustrated at Blocks  162 - 164  are preferably repeated for each data system. 
     It should be noted that the protocol and metric data store  91 ″ is but one example exemplary of a protocol preference ranking technique that may be used in accordance with the present invention. Protocol preferences may be inherent in the ordering of a list of supported protocols, for example. 
     Further criteria than metrics or overall preferences may also be considered when selecting a protocol. The type of client from which the access command is received may also affect protocol selection. Where the access command is received from a POP client, for example, many of the enhanced features supported by OWA cannot be represented in POP for transfer to the device. If a user has only one type of client for accessing the protocol interface device  14 ″, then the per-account information may be adapted to reflect the type of client or to limit the list of supported protocol based on the type of client. Otherwise, a further step in protocol selection may be to determine the type of client from which an access request is received. 
     Alternatively, a most capable protocol supported by a data system to be accessed may always be selected, and any incompatibility between the selected access protocol and the protocol supported by the client is handled during translation of data to the client protocol. Portions of data corresponding to elements of the interface protocol that are supported by the client protocol are translated, whereas non-supported interface protocol elements are ignored or processed according to a default or error processing scheme. 
     Generally speaking, clients often access servers through proxies. Also, the latency is often positively correlated to the cardinality of the collection being accessed (e.g., number of email messages in the mailbox being accessed). As will be evident from the following description, the present invention provides an apparatus and technique that may be used by the proxy to give the client the illusion that the collection being accessed is smaller than it really is. For example, a proxy may show only the 100 most recent messages in a mailbox, while the mailbox itself has 2000+ messages. The present invention advantageously allows this proxy to select a small subset of the collection that can be presented to the client in lieu of the entire collection without a significant impact to the user experience. 
     More particularly, turning now to  FIG. 10 , another advantageous embodiment of the protocol interface device  14 ′″ is now described. Generally speaking, when a data access request is received from a client, the protocol interface device  14 ′″ accesses one or more of the data systems  24 ′″,  26 ′″. However, in some cases accessing the data systems and providing a response to the client might otherwise cause timeouts for certain client protocols, and longer than desired wait times for a user of a client after a request has been sent. Yet, in accordance with the present aspect of the invention, certain data may be stored at the protocol interface device  14 ′″ which may be used to reduce response times. 
     More particularly, the protocol engine module  32 ′″ polls the data systems  24 ′″,  26 ′″ to determine whether they currently store data items associated with users that have been configured for access thereof. Users are configured in the protocol interface device  14 ′″ by establishing a user account associated therewith, for example. Polling is preferably performed in accordance with a polling interval. The polling interface may be a static predetermined polling interval, or an adaptive polling interval that can be adjusted based on operating conditions or the occurrence of particular events, as will be appreciated by those skilled in the art. 
     In response to a poll from the protocol engine module  32 ′″, a given data system  24 ′″,  26 ′″ returns data items, or at least data item identifiers that can be used to retrieve the data items, to the protocol interface device  14 ′″. These data items or identifiers are then stored by the protocol engine module  32 ′″ in the data store or memory  92 ′″. 
     In particular, the protocol engine module  32 ′″ may determine whether new data items for a user are stored in any of the data systems  24 ′″,  26 ′″. Where the data systems  24 ′″,  26 ′″ are e-mail systems, for example, the protocol engine module  32 ′″ queries mailboxes associated with each user configured for e-mail access through the protocol interface device  14 ′″. For each mailbox query, a mail system returns, at a minimum, a list of unique identifiers (UIDs) associated with e-mail messages stored in the mailbox. 
     A current UID list is then compared with a previous UID list for the mailbox in the UID store  92 ′″ to determine whether new messages have been stored in the mailbox at the mail system. If new messages are detected, an alert is preferably sent to a user&#39;s client by the protocol engine module  32 ′″ in cooperation with the front-end proxy module  30 ′″ (or another component of the protocol interface device  14 ′″), and the current UID list including the new messages is stored to the UID store  92 ′″. 
     One of the most common data access operations is viewing a listing of data items currently stored at data systems, especially where the data items are messages stored on mail systems. As described above, the protocol engine module  32 ′″ polls one or more of the data systems  24 ′″,  26 ′″ to detect new data items based on a list of UIDs stored in the UID store  92 ′″. Therefore, the protocol interface device  14 ′″ has a local listing of UIDs of data items that were stored at the data systems  24 ′″,  26 ′″ the last time the data systems were polled. 
     In accordance with the present aspect of the invention, the protocol engine module  32 ′″ retrieves the stored UID list from the UID store  92 ′″ when a “view items” or similar access request is received. This stored UID list, which is accurate to within the current polling interval, is then returned to the requesting client. This provides a much faster response time than accessing the data systems  24 ′″,  26 ′″ when the request is received, as will be appreciated by those skilled in the art. 
     In the case of a POP client, for example, the client times out if no response to a request is received within 30 seconds. Where the POP client is operating on a mobile wireless communications device, latency within the wireless communications network can cause delays that are significant relative to this limited response time. The faster response time associated with providing a stored UID list in response to a data access request is particularly advantageous in these types of scenarios. Even in the absence of such time constraints, a faster response time enhances the user experience at a client by reducing the wait time between sending a data access request and receiving a response. 
     As described above, the stored UID list is accurate to within the polling interval. When the stored UID list is provided to a client in response to a data access request, the protocol engine module  32 ′″ preferably polls the data system(s)  24 ′″,  26 ′″ to determine whether the stored UID list is still accurate. If new items have been stored at the data system(s)  24 ′″,  26 ′″ since the last poll, then a new UID list is sent to the client. This further polling of the data systems  24 ′″,  26 ′″ is performed either according to the polling interval or initiated by the data access request. 
     It will be appreciated that the preceding description relates to “view items” or similar data access requests. Other types of data access requests may be processed by other components or modules of the protocol interface device  14 ′″. For example, such data access requests are translated, if necessary, by the front-end proxy module  30 ′″, as described above. 
     The protocol interface device  14 ′″ thereby allows access to the data systems  24 ′″,  26 ′″, and provides for reduced response times for various types of data access requests. Through the protocol interface device  14 ′″, a client compatible with any of the protocols handled by the front-end proxy module  30 ′″ is provided access to one or more of the data systems  24 ′″,  26 ′″. The client itself need not support the access protocol or scheme associated with the data system(s)  24 ′″,  26 ′″ to be accessed, as noted above. 
     A method of reducing response times for data system access requests using the protocol interface device  14 ′″ is now described with respect to  FIG. 17 . Beginning at Block  170 , a data access request is received at Block  171 . A determination is then made, at Block  172 , as to whether data pertinent to the data access request (i.e., a UID list) is locally stored. Where such data is in a local store  92 ′″, then the stored data is provided to the requesting client, at Block  173 . After the stored data has been transmitted to the client, or if no such data has been stored, the data system(s)  24 ′″,  26 ′″ to which the data access request relates is polled, at Block  174 . 
     An optional step of determining whether the polled data received in response to a poll is different from the stored data may then be performed at Block  175 . If so, this means that there is new data stored on the data system(s)  24 ′″,  26 ′″, and the data received in response to the poll is provided to the client, at Block  176 . It is also locally stored in the data store  92 ′″, at Block  177 , thus concluding the illustrated method (Block  178 ). 
     By way of example, data access systems and methods according to aspects of the invention may be applied to other types of data storage devices than mail systems, and other protocols and access schemes than those specifically described above and shown in the drawings. 
     Additional features of the invention may be found in co-pending applications entitled COMMUNICATIONS SYSTEM INCLUDING PROTOCOL INTERFACE DEVICE PROVIDING ENHANCED OPERATING PROTOCOL SELECTION FEATURES AND RELATED METHODS, attorney docket number ID-495; COMMUNICATIONS SYSTEM INCLUDING PROTOCOL INTERFACE FOR MULTIPLE OPERATING PROTOCOLS AND RELATED METHODS, attorney docket number ID-493; COMMUNICATIONS SYSTEM PROVIDING MULTI-LAYERED EXTENSIBLE PROTOCOL INTERFACE AND RELATED METHODS, attorney docket number ID-503; COMMUNICATIONS SYSTEM PROVIDING EXTENSIBLE PROTOCOL TRANSLATION FEATURES AND RELATED METHODS, attorney docket number ID-507; COMMUNICATIONS SYSTEM WITH DATA STORAGE DEVICE INTERFACE PROTOCOL CONNECTORS AND RELATED METHODS, attorney docket number ID-506; and COMMUNICATIONS SYSTEM PROVIDING EXTENSIBLE PROTOCOL TRANSLATION AND CONFIGURATION FEATURES AND RELATED METHODS, attorney docket number ID-502; the entire disclosures of which are hereby incorporated herein by reference. 
     Example 
     An exemplary hand-held mobile wireless communications device  1000  that can be used in the present invention is further described in the example below with reference to  FIG. 18 . The device  1000  includes a housing  1200 , a keyboard  1400  and an output device  1600 . The output device shown is a display  1600 , which is preferably a full graphic LCD. Other types of output devices may alternatively be utilized. A processing device  1800  is contained within the housing  1200  and is coupled between the keyboard  1400  and the display  1600 . The processing device  1800  controls the operation of the display  1600 , as well as the overall operation of the mobile device  1000 , in response to actuation of keys on the keyboard  1400  by the user. 
     The housing  1200  may be elongated vertically, or may take on other sizes and shapes (including clamshell housing structures). The keyboard may include a mode selection key, or other hardware or software for switching between text entry and telephony entry. 
     In addition to the processing device  1800 , other parts of the mobile device  1000  are shown schematically in  FIG. 18 . These include a communications subsystem  1001 ; a short-range communications subsystem  1020 ; the keyboard  1400  and the display  1600 , along with other input/output devices  1060 ,  1080 ,  1100  and  1120 ; as well as memory devices  1160 ,  1180  and various other device subsystems  1201 . The mobile device  1000  is preferably a two-way RF communications device having voice and data communications capabilities. In addition, the mobile device  1000  preferably has the capability to communicate with other computer systems via the Internet. 
     Operating system software executed by the processing device  1800  is preferably stored in a persistent store, such as the flash memory  1160 , but may be stored in other types of memory devices, such as a read only memory (ROM) or similar storage element. In addition, system software, specific device applications, or parts thereof, may be temporarily loaded into a volatile store, such as the random access memory (RAM)  1180 . Communications signals received by the mobile device may also be stored in the RAM  1180 . 
     The processing device  1800 , in addition to its operating system functions, enables execution of software applications  1300 A- 1300 N on the device  1000 . A predetermined set of applications that control basic device operations, such as data and voice communications  1300 A and  1300 B, may be installed on the device  1000  during manufacture. In addition, a personal information manager (PIM) application may be installed during manufacture. The PIM is preferably capable of organizing and managing data items, such as e-mail, calendar events, voice mails, appointments, and task items. The PIM application is also preferably capable of sending and receiving data items via a wireless network  1401 . Preferably, the PIM data items are seamlessly integrated, synchronized and updated via the wireless network  1401  with the device user&#39;s corresponding data items stored or associated with a host computer system. 
     Communication functions, including data and voice communications, are performed through the communications subsystem  1001 , and possibly through the short-range communications subsystem. The communications subsystem  1001  includes a receiver  1500 , a transmitter  1520 , and one or more antennas  1540  and  1560 . In addition, the communications subsystem  1001  also includes a processing module, such as a digital signal processor (DSP)  1580 , and local oscillators (LOs)  1601 . The specific design and implementation of the communications subsystem  1001  is dependent upon the communications network in which the mobile device  1000  is intended to operate. For example, a mobile device  1000  may include a communications subsystem  1001  designed to operate with the Mobitex™, Data TAC™ or General Packet Radio Service (GPRS) mobile data communications networks, and also designed to operate with any of a variety of voice communications networks, such as AMPS, TDMA, CDMA, PCS, GSM, etc. Other types of data and voice networks, both separate and integrated, may also be utilized with the mobile device  1000 . 
     Network access requirements vary depending upon the type of communication system. For example, in the Mobitex and DataTAC networks, mobile devices are registered on the network using a unique personal identification number or PIN associated with each device. In GPRS networks, however, network access is associated with a subscriber or user of a device. A GPRS device therefore requires a subscriber identity module, commonly referred to as a SIM card, in order to operate on a GPRS network. 
     When required network registration or activation procedures have been completed, the mobile device  1000  may send and receive communications signals over the communication network  1401 . Signals received from the communications network  1401  by the antenna  1540  are routed to the receiver  1500 , which provides for signal amplification, frequency down conversion, filtering, channel selection, etc., and may also provide analog to digital conversion. Analog-to-digital conversion of the received signal allows the DSP  1580  to perform more complex communications functions, such as demodulation and decoding. In a similar manner, signals to be transmitted to the network  1401  are processed (e.g. modulated and encoded) by the DSP  1580  and are then provided to the transmitter  1520  for digital to analog conversion, frequency up conversion, filtering, amplification and transmission to the communication network  1401  (or networks) via the antenna  1560 . 
     In addition to processing communications signals, the DSP  1580  provides for control of the receiver  1500  and the transmitter  1520 . For example, gains applied to communications signals in the receiver  1500  and transmitter  1520  may be adaptively controlled through automatic gain control algorithms implemented in the DSP  1580 . 
     In a data communications mode, a received signal, such as a text message or web page download, is processed by the communications subsystem  1001  and is input to the processing device  1800 . The received signal is then further processed by the processing, device  1800  for an output to the display  1600 , or alternatively to some other auxiliary I/O device  1060 . A device user may also compose data items, such as e-mail messages, using the keyboard  1400  and/or some other auxiliary I/O device  1060 , such as a touchpad, a rocker switch, a thumb-wheel, or some other type of input device. The composed data items may then be transmitted over the communications network  1401  via the communications subsystem  1001 . 
     In a voice communications mode, overall operation of the device is substantially similar to the data communications mode, except that received signals are output to a speaker  1100 , and signals for transmission are generated by a microphone  1120 . Alternative voice or audio I/O subsystems, such as a voice message recording subsystem, may also be implemented on the device  1000 . In addition, the display  1600  may also be utilized in voice communications mode, for example to display the identity of a calling party, the duration of a voice call, or other voice call related information. 
     The short-range communications subsystem enables communication between the mobile device  1000  and other proximate systems or devices, which need not necessarily be similar devices. For example, the short-range communications subsystem may include an infrared device and associated circuits and components, or a Bluetooth™ communications module to provide for communication with similarly-enabled systems and devices. 
     Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims. 
     Computer Program Listings 
     Program Listing #1—Exemplary Authentication Request 
       
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 PROPFIND /ups HTTP/1.1 
               
               
                   
                 Depth: 0 
               
               
                   
                 Brief: t 
               
               
                   
                 Pragma: no-cache 
               
               
                   
                 Content-Type: text/xml 
               
               
                   
                 X_UP_LOGIN: 
               
            
           
           
               
            
               
                 svr=login.oscar.aol.com&amp;prt=5190&amp;ssl=0&amp;pcol=aol&amp;uid= 
               
               
                 ******&amp;pwd=******&amp;pwp= X_UP_SYNC: false 
               
            
           
           
               
               
            
               
                   
                 X_UP_REFRESH_CACHE: force 
               
               
                   
                 X_UP_NEWCON: 1 
               
               
                   
                 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0) 
               
               
                   
                 Connection: Keep-Alive 
               
               
                   
                 Host: localhost:9080 
               
               
                   
                 Content-Length: 664 
               
               
                   
                 &lt;?xml version=“1.0”?&gt; 
               
               
                   
                 &lt;D:propfind  xmlns:D=“DAV:” 
               
            
           
           
               
            
               
                 xmlns:h=“http://schemas.microsoft.com/hotmail/” 
               
               
                 xmlns:hm=“urn:schemas:httpmail:” 
               
               
                 xmlns:up=“urn:schemas:corp:universalproxy” &gt; 
               
            
           
           
               
               
            
               
                   
                 &lt;D:prop&gt; 
               
               
                   
                  &lt;hm:contacts/&gt; 
               
               
                   
                   &lt;hm:calendar/&gt; 
               
               
                   
                   &lt;hm:journal/&gt; 
               
               
                   
                   &lt;hm:notes/&gt; 
               
               
                   
                   &lt;hm:inbox/&gt; 
               
               
                   
                   &lt;hm:outbox/&gt; 
               
               
                   
                   &lt;hm:sendmsg/&gt; 
               
               
                   
                   &lt;hm:sentitems/&gt; 
               
               
                   
                   &lt;hm:deleteditems/&gt; 
               
               
                   
                   &lt;hm:drafts/&gt; 
               
               
                   
                   &lt;hm:msgfolderroot/&gt; 
               
               
                   
                   &lt;up:corporatecontacts/&gt; 
               
               
                   
                   &lt;h:maxpoll/&gt; 
               
               
                   
                   &lt;h:sig/&gt; 
               
               
                   
                  &lt;/D:prop&gt; 
               
               
                   
                 &lt;/D:propfind&gt; 
               
               
                   
                 HTTP/1.1 207 Multi-Status 
               
               
                   
                 Set-Cookie: 
               
               
                   
                 JSESSIONID=C70CD1AED7D2BE210B34D93F7ACD6935; 
               
               
                   
                 Path=/ups 
               
               
                   
                 Content-Type: text/xml 
               
               
                   
                 Transfer-Encoding: chunked 
               
               
                   
                 Date: Wed, 06 Aug 2003 18:20:28 GMT 
               
               
                   
                 Server: Apache Coyote/1.0 
               
               
                   
                 &lt;?xml version=“1.0” encoding=“UTF-8”?&gt; 
               
               
                   
                 &lt;D:multistatus   xmlns:D=“DAV:” 
               
               
                   
                 xmlns:up=“urn:schemas:corp:universalproxy” 
               
               
                   
                 xmlns:c=“urn:schemas:calendar:” xmlns:a=“urn:schemas:contacts:” 
               
               
                   
                 xmlns:hm=“urn:schemas:httpmail:” 
               
               
                   
                 xmlns:m=“urn:schemas:mailheader:”&gt; 
               
               
                   
                  &lt;D:response&gt; 
               
               
                   
                   &lt;D:href&gt;http://localhost:9080/ups/&lt;/D:href&gt; 
               
               
                   
                   &lt;D:propstat&gt; 
               
               
                   
                    &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                    &lt;D:prop&gt; 
               
               
                   
                     &lt;hm:inbox&gt;http://localhost:9080/ups/INBOX/&lt;/hm:inbox&gt; 
               
               
                   
                 &lt;hm:sendmsg&gt;http://localhost:9080/ups/ 
               
               
                   
                 AOL_MAIL_SUBMISSION_URL/&lt;/hm:sendmsg&gt; 
               
               
                   
                     &lt;hm:sentitems&gt;http://localhost:9080/ups/Sent Items/ 
               
               
                   
                     &lt;/hm:sentitems&gt; 
               
               
                   
                     &lt;hm:msgfolderroot&gt;http://localhost:9080/ups/ 
               
               
                   
                     &lt;/hm:msgfolderroot&gt; 
               
               
                   
                    &lt;/D:prop&gt; 
               
               
                   
                   &lt;/D:propstat&gt; 
               
               
                   
                  &lt;/D:response&gt; 
               
               
                   
                 &lt;/D:multistatus&gt; 
               
               
                   
                   
               
            
           
         
       
     
     Program Listing #2—Exemplary Inbox Request 
       
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 Query Folder Capabilities: 
               
               
                   
                 REQUEST: 
               
               
                   
                 OPTIONS /ups/INBOX/ HTTP/1.1 
               
               
                   
                 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0) 
               
               
                   
                 Connection: Keep-Alive 
               
               
                   
                 Host: localhost:9080 
               
               
                   
                 Cookie: JSESSIONID=C70CD1AED7D2BE210B34D93F7ACD6935 
               
               
                   
                 Content-Length: 0 
               
               
                   
                 RESPONSE: 
               
               
                   
                 HTTP/1.1 200 OK 
               
               
                   
                 allow: OPTIONS, PROPFIND, MOVE, DELETE, BDELETE, 
               
               
                   
                 BMOVE, SEARCH dasl: 
               
               
                   
                 &lt;urn:schemas:corp:universalproxy:basicsearch&gt; 
               
               
                   
                 Content-Type: text/plain 
               
               
                   
                 Content-Length: 0 
               
               
                   
                 Date: Wed, 06 Aug 2003 18:20:28 GMT 
               
               
                   
                 Server: Apache Coyote/1.0 
               
               
                   
                 List messages in INBOX: 
               
               
                   
                 REQUEST: 
               
               
                   
                 PROPFIND /ups/INBOX/ HTTP/1.1 
               
               
                   
                 Range: rows=0-24 
               
               
                   
                 Depth: 1,noroot 
               
               
                   
                 Brief: t 
               
               
                   
                 Pragma: no-cache 
               
               
                   
                 Content-Type: text/xml 
               
               
                   
                 X_UP_REFRESH_CACHE: force 
               
               
                   
                 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0) 
               
               
                   
                 Connection: Keep-Alive 
               
               
                   
                 Host: localhost:9080 
               
               
                   
                 Cookie: JSESSIONID=C70CD1AED7D2BE210B34D93F7ACD6935 
               
               
                   
                 Content-Length: 586 
               
               
                   
                 &lt;?xml version=“1.0”?&gt; 
               
               
                   
                 &lt;D:propfind xmlns:D=“DAV:” xmlns:hm=“urn:schemas:httpmail:” 
               
            
           
           
               
            
               
                 xmlns:m=“urn:schemas:mailheader:” 
               
               
                 xmlns:up=“urn:schemas:corp:universalproxy”&gt; 
               
            
           
           
               
               
            
               
                   
                  &lt;D:prop&gt; 
               
               
                   
                   &lt;D:uid/&gt; 
               
               
                   
                   &lt;D:isfolder/&gt; 
               
               
                   
                   &lt;D:ishidden/&gt; 
               
               
                   
                   &lt;hm:read/&gt; 
               
               
                   
                   &lt;hm:hasattachment/&gt; 
               
               
                   
                   &lt;hm:importance/&gt; 
               
               
                   
                   &lt;m:from/&gt; 
               
               
                   
                   &lt;m:subject/&gt; 
               
               
                   
                   &lt;m:date/&gt; 
               
               
                   
                   &lt;up:isdeleted/&gt; 
               
               
                   
                   &lt;D:getcontentlength/&gt; 
               
               
                   
                   &lt;D:contentclass/&gt; 
               
               
                   
                  &lt;/D:prop&gt; 
               
               
                   
                 &lt;/D:propfind&gt; 
               
               
                   
                 RESPONSE: 
               
               
                   
                 HTTP/1.1 207 Multi-Status 
               
               
                   
                 Content-Range: rows 0-8; total=9 
               
               
                   
                 Content-Type: text/xml 
               
               
                   
                 Transfer-Encoding: chunked 
               
               
                   
                 Date: Wed, 06 Aug 2003 18:20:28 GMT 
               
               
                   
                 Server: Apache Coyote/1.0 
               
               
                   
                 &lt;?xml version=“1.0” encoding=“UTF-8”?&gt; 
               
               
                   
                 &lt;D:multistatus   xmlns:D=“DAV:” 
               
            
           
           
               
            
               
                 xmlns:up=“urn:schemas:corp:universalproxy” 
               
               
                 xmlns:c=“urn:schemas:calendar:” xmlns:a=“urn:schemas:contacts:” 
               
               
                 xmlns:hm=“urn:schemas:httpmail:” 
               
               
                 xmlns:m=“urn:schemas:mailheader:”&gt; 
               
            
           
           
               
               
            
               
                   
                 &lt;D:contentrange&gt;0-8&lt;/D:contentrange&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6623963;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;3ac59b38c08ad3356435efea144660e3&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;0&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;0&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;Mail Delivery Subsystem 
               
               
                   
                    &amp;lt;MAILER-DAEMON@aol.com&gt;&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;Returned mail: User unknown&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-08-05T23:12:48Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;3247&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content-classes:message&lt;/ 
               
               
                   
                    D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6623954;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;51073b22a28c2820115bc80d42e8c6ec&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;1&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;0&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;johnsmith@demo.com&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;Re: Test #1-All -French template&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-08-05T23:10:30Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;1577&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content- 
               
               
                   
                    classes:message&lt;/D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6623926;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;b072c3748ceff1320f9fa746f797e64b&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;1&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;0&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;johnsmith@demo.com&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;Re: xxxFWD: Re: Test #1&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-08-05T23:07:18Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;1927&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content- 
               
               
                   
                    classes:message&lt;/D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6623922;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;11f1c8e69555d33971aea12c09be5021&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;1&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;0&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;johnsmith@demo.com&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;Re: xxxFWD: Re: Test #1&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-08-05T23:06:45Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;1930&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content- 
               
               
                   
                    classes:message&lt;/D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6623915;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;55bc30adfb4fb66f3d11b0416c82b701&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;1&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;1&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;johnsmith@demo.com&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;xxxFWD: Re: Test #1&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-08-05T23:05:27Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;3254&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content- 
               
               
                   
                    classes:message&lt;/D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6623910;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;07cdf24a06f8e849754f90fe6dc8bf4f&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;1&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;0&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;johnsmith@demo.com&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;Re: Test #1-All&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-08-05T23:04:31Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;1258&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content- 
               
               
                   
                    classes:message&lt;/D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6623909;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;0e79a3593253ffb9596bf9d86873f498&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;1&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;0&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;johnsmith@demo.com&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;Re: Test #1&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-08-05T23:04:13Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;1241&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content- 
               
               
                   
                    classes:message&lt;/D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6605332;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;6060b944e60256c814498af29e5f0e47&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;0&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;0&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;aolmbrsecurity@aol.com&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;Security Notice to AOL Members&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-08-01T23:00:58Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;5137&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content- 
               
               
                   
                    classes:message&lt;/D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;D:response&gt; 
               
               
                   
                  &lt;D:href&gt;http://localhost:9080/ups/INBOX/6567082;1&lt;/D:href&gt; 
               
               
                   
                  &lt;D:propstat&gt; 
               
               
                   
                   &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                   &lt;D:prop&gt; 
               
               
                   
                    &lt;D:uid&gt;f47b72c8c1aa91458f40f81fce3b5e05&lt;/D:uid&gt; 
               
               
                   
                    &lt;D:isfolder&gt;0&lt;/D:isfolder&gt; 
               
               
                   
                    &lt;D:ishidden&gt;0&lt;/D:ishidden&gt; 
               
               
                   
                    &lt;hm:read&gt;0&lt;/hm:read&gt; 
               
               
                   
                    &lt;hm:hasattachment&gt;0&lt;/hm:hasattachment&gt; 
               
               
                   
                    &lt;hm:importance&gt;1&lt;/hm:importance&gt; 
               
               
                   
                    &lt;m:from&gt;aolmemberinfo@aol.com&lt;/m:from&gt; 
               
               
                   
                    &lt;m:subject&gt;Coming Soon - AOL 9.0 Optimized&lt;/m:subject&gt; 
               
               
                   
                    &lt;m:date&gt;2003-07-25T21:15:22Z&lt;/m:date&gt; 
               
               
                   
                    &lt;up:isdeleted&gt;0&lt;/up:isdeleted&gt; 
               
               
                   
                    &lt;D:getcontentlength&gt;10012&lt;/D:getcontentlength&gt; 
               
               
                   
                    &lt;D:contentclass&gt;urn:content- 
               
               
                   
                    classes:message&lt;/D:contentclass&gt; 
               
               
                   
                   &lt;/D:prop&gt; 
               
               
                   
                  &lt;/D:propstat&gt; 
               
               
                   
                 &lt;/D:response&gt; 
               
               
                   
                 &lt;/D:multistatus&gt; 
               
               
                   
                   
               
            
           
         
       
     
     Program Listing #3—Exemplary Folder Search Request 
       
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 Capabilities of folder: 
               
               
                   
                 REQUEST: 
               
               
                   
                 OPTIONS /ups HTTP/1.1 
               
               
                   
                 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0) 
               
               
                   
                 Connection: Keep-Alive 
               
               
                   
                 Host: localhost:9080 
               
               
                   
                 Cookie: JSESSIONID=C70CD1AED7D2BE210B34D93F7ACD6935 
               
               
                   
                 Content-Length: 0 
               
               
                   
                 RESPONSE: 
               
               
                   
                 HTTP/1.1 200 OK 
               
               
                   
                 allow: OPTIONS, PROPFIND, MOVE, DELETE, BDELETE, 
               
               
                   
                 BMOVE, SEARCH dasl: 
               
               
                   
                 &lt;urn:schemas:corp:universalproxy:basicsearch&gt; 
               
               
                   
                 Content-Type: text/plain 
               
               
                   
                 Content-Length: 0 
               
               
                   
                 Date: Wed, 06 Aug 2003 18:20:28 GMT 
               
               
                   
                 Server: Apache Coyote/1.0 
               
               
                   
                 Search for folders: 
               
               
                   
                 REQUEST: 
               
               
                   
                 SEARCH /ups HTTP/1.1 
               
               
                   
                 Depth: 1,noroot 
               
               
                   
                 Brief: t 
               
               
                   
                 Pragma: no-cache 
               
               
                   
                 Content-Type: text/xml 
               
               
                   
                 User-Agent: Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0) 
               
               
                   
                 Connection: Keep-Alive 
               
               
                   
                 Host: localhost:9080 
               
               
                   
                 Cookie: JSESSIONID=C70CD1AED7D2BE210B34D93F7ACD6935 
               
               
                   
                 Content-Length: 922 
               
               
                   
                 &lt;?xml version=“1.0”?&gt; 
               
               
                   
                 &lt;D:searchrequest xmlns:D=“DAV:” 
               
               
                   
                 xmlns:t=“urn:schemas:corp:universalproxy”&gt; 
               
               
                   
                  &lt;t:basicsearch&gt; 
               
               
                   
                   &lt;D:select&gt; 
               
               
                   
                    &lt;D:prop&gt;&lt;D:uid/&gt;&lt;/D:prop&gt; 
               
               
                   
                    &lt;D:prop&gt;&lt;D:contentclass/&gt;&lt;/D:prop&gt; 
               
               
                   
                    &lt;D:prop&gt;&lt;D:displayname/&gt;&lt;/D:prop&gt; 
               
               
                   
                   &lt;/D:select&gt; 
               
               
                   
                   &lt;D:from&gt; 
               
               
                   
                    &lt;D:scope&gt; 
               
               
                   
                     &lt;D:href&gt;url&lt;/D:href&gt; 
               
               
                   
                     &lt;D:depth&gt;1&lt;/D:depth&gt; 
               
               
                   
                    &lt;/D:scope&gt; 
               
               
                   
                   &lt;/D:from&gt; 
               
               
                   
                   &lt;D:where&gt; 
               
               
                   
                    &lt;D:eq&gt; 
               
               
                   
                     &lt;D:prop&gt;&lt;D:contentclass/&gt;&lt;/D:prop&gt; 
               
               
                   
                     &lt;D:literal&gt;urn:content-classes:mailfolder&lt;/D:literal&gt; 
               
               
                   
                    &lt;/D:eq&gt; 
               
               
                   
                   &lt;/D:where&gt; 
               
               
                   
                  &lt;/t:basicsearch&gt; 
               
               
                   
                 &lt;/D:searchrequest&gt; 
               
               
                   
                 RESPONSE: 
               
               
                   
                 HTTP/1.1 207 Multi-Status 
               
               
                   
                 Content-Type: text/xml 
               
               
                   
                 Transfer-Encoding: chunked 
               
               
                   
                 Date: Wed, 06 Aug 2003 18:20:28 GMT 
               
               
                   
                 Server: Apache Coyote/1.0 
               
               
                   
                 &lt;?xml version=“1.0” encoding=“UTF-8”?&gt; 
               
               
                   
                 &lt;D:multistatus   xmlns:D=“DAV:” 
               
            
           
           
               
            
               
                 xmlns:up=“urn:schemas:corp:universalproxy” 
               
               
                 xmlns:c=“urn:schemas:calendar:” xmlns:a=“urn:schemas:contacts:” 
               
               
                 xmlns:hm=“urn:schemas:httpmail:” 
               
               
                 xmlns:m=“urn:schemas:mailheader:”&gt; 
               
            
           
           
               
               
            
               
                   
                  &lt;D:response&gt; 
               
               
                   
                   &lt;D:href&gt;http://localhost:9080/ups/INBOX/&lt;/D:href&gt; 
               
               
                   
                   &lt;D:propstat&gt; 
               
               
                   
                    &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                    &lt;D:prop&gt; 
               
               
                   
                     &lt;D:uid&gt;c90d66b2362a1a0bc3df1852021a6f63&lt;/D:uid&gt; 
               
               
                   
                     &lt;D:contentclass&gt;urn:content- 
               
               
                   
                     classes:mailfolder&lt;/D:contentclass&gt; 
               
               
                   
                     &lt;D:displayname&gt;INBOX/&lt;/D:displayname&gt; 
               
               
                   
                    &lt;/D:prop&gt; 
               
               
                   
                   &lt;/D:propstat&gt; 
               
               
                   
                  &lt;/D:response&gt; 
               
               
                   
                  &lt;D:response&gt; 
               
               
                   
                   &lt;D:href&gt;http://localhost:9080/ups/VOICE-MAIL/&lt;/D:href&gt; 
               
               
                   
                   &lt;D:propstat&gt; 
               
               
                   
                    &lt;D:status&gt;HTTP/1.1 200 OK&lt;/D:status&gt; 
               
               
                   
                    &lt;D:prop&gt; 
               
               
                   
                     &lt;D:uid&gt;cabbce34709ab79d2ad2d5334d998272&lt;/D:uid&gt; 
               
               
                   
                     &lt;D:contentclass&gt;urn:content- 
               
               
                   
                     classes:mailfolder&lt;/D:contentclass&gt; 
               
               
                   
                     &lt;D:displayname&gt;VOICE-MAIL/&lt;/D:displayname&gt; 
               
               
                   
                    &lt;/D:prop&gt; 
               
               
                   
                   &lt;/D:propstat&gt; 
               
               
                   
                  &lt;/D:response&gt; 
               
               
                   
                 &lt;/D:multistatus&gt; 
               
               
                   
                   
               
            
           
         
       
     
     Program Listing #4—Exemplary Configuration File 
       
     
       
         
           
               
             
               
                   
               
             
            
               
                 &lt;resource 
               
               
                   contentclass=“urn:content-classes:mailfolder” 
               
               
                   javaclass=“com.teamon.proxy.data.impl.MailFolderImpl” 
               
               
                   responsecacheduration=“0” 
               
               
                   cachestrength=“0”&gt; 
               
               
                  &lt;request method=“PROPFIND”&gt; 
               
               
                   &lt;header name=“Brief”  value=“t” /&gt; 
               
               
                   &lt;header name=“Content-Type” value=“text/xml”/&gt; 
               
               
                   &lt;header name=“Depth”  value=“1,noroot”/&gt; 
               
               
                   &lt;header name=“Range”  value=“rows=$rangeStart$-$rangeEnd$”/&gt; 
               
               
                   &lt;header name=“Pragma”  value=“no-cache”/&gt; 
               
               
                   &lt;header name=“X_UP_REFRESH_CACHE” value=“force” /&gt; 
               
               
                   &lt;body&gt;&lt;![CDATA[ 
               
               
                    &lt;?xml version=“1.0”?&gt; 
               
               
                    &lt;D:propfind 
               
               
                      xmlns:D=“DAV:” 
               
               
                      xmlns:hm=“urn:schemas:httpmail:” 
               
               
                      xmlns:m=“urn:schemas:mailheader:” 
               
               
                      xmlns:up=“urn:schemas:teamon:universalproxy”&gt; 
               
               
                     &lt;D:prop&gt; 
               
               
                      &lt;D:uid/&gt; 
               
               
                      &lt;D:isfolder/&gt; 
               
               
                      &lt;D:ishidden/&gt; 
               
               
                      &lt;hm:read/&gt; 
               
               
                      &lt;hm:hasattachment/&gt; 
               
               
                      &lt;hm:importance/&gt; 
               
               
                      &lt;m:from/&gt; 
               
               
                      &lt;m:subject/&gt; 
               
               
                      &lt;m:date/&gt; 
               
               
                      &lt;up:isdeleted/&gt; 
               
               
                      &lt;D:getcontentlength/&gt; 
               
               
                      &lt;D:contentclass/&gt; 
               
               
                     &lt;/D:prop&gt; 
               
               
                    &lt;/D:propfind&gt; 
               
               
                    ]]&gt; 
               
               
                   &lt;/body&gt; 
               
               
                  &lt;/request&gt; 
               
               
                 &lt;/resource&gt;