Abstract:
A method in a distributed application environment is provided. The method includes, in a network, encapsulating data requests generated by an application in a first system, transferring the encapsulated data requests to a second system, executing the encapsulated data requests in the second system, and processing in the first system responses generated by the encapsulated data requests in the second system.

Description:
CLAIM OF PRIORITY 
   This application claims priority under 35 USC §119(e) to U.S. patent application Ser. No. 60/257,212, filed on Dec. 20, 2000, the entire contents of which are hereby incorporated by reference. 

   TECHNICAL FIELD 
   This invention relates to rapid development in a distributed application environment. 
   BACKGROUND 
   There is a need to interact with applications over the Internet. The development of web browsers aided this need. For example, a web browser sends a Hyper Text Markup Language (HTML) request to a web server via Hyper Text Transfer Protocol (HTTP). The web server receives the request and routes it to an appropriate database via an Open Database Connection (ODBC). Active Server Pages (ASP) or Java Scripts are used on the web server to translate and determine location and routing of the HTML requests and responses from the application database. The responses are translated into an HTML web page and sent back to the web browser using HTTP. 
   Application servers speed up the access to application databases. Servlets or enterprise java beans (EJB) reside on the application server and are “hardcoded” to make specific database calls. The requests from the application server are made through Java Database Connections (JDBC). 
   SUMMARY 
   In an aspect, the invention features a method including in a network, encapsulating data requests generated by an application in a first system, transferring the encapsulated data requests to a second system, executing the encapsulated data requests in the second system, and processing in the first system responses generated by the encapsulated data requests in the second system. 
   Embodiments may include one or more of the following. Encapsulating may include generating an Extensible Markup Language (XML) structure for each data request, and converting the XML structure to an XML request. The XML structure may include a variable stream of data stored in memory of the first system, the stream including an XML element for each request. The XML element may be a class object whose data is stored to generate XML. The XML element may include data from a data set object. The data set object may include table dictionaries, column names and data from record sets, and stored procedure parameters. 
   Transferring may include a text transmission protocol and the test transmission protocol may be Hypertext Transfer Protocol. 
   Executing may include de-encapsulating the encapsulated data requests by parsing into request statements, and executing the request statements. The method may also include translating responses from the executed request statements into an XML format, and sending the XML formatted responses to the first system. 
   In another aspect, the invention features a distributed application method including converting application requests in a first system, transmitting the converted application requests to a second system over a network, parsing the converted application requests in the second system into request statements, and executing the request statements in the second system. 
   Embodiments may include one or more of the following. Converting may include generating a data structure for storing data and parameters related to an application that produced the application requests, translating the application requests into a standardized delimited data structure stored in a memory of the first system, and transforming the standardized delimited data structure in conjunction with the data structure into a stream of text based data utilizing a Extensible Markup Language (XML) format. 
   Parsing may include breaking down the converted application requests to an executable command format utilizing data and parameters related to an application. 
   Executing may also include evaluating executable commands prior to execution in the second system and/or evaluating results generated by the executable commands. 
   The method may also include converting the results into a stream of text based data in a standardized XML format, and transmitting the converted results over the network to the first system. 
   In another aspect, the invention features an application server method including generating a first data structure for storing data and parameters related to an application residing in the server, translating application requests from the application into a delimited second data structure stored in a memory, generating a stream of text-based data in an Extensible Markup Language (XML) format from the second data structure. 
   Embodiments may include one or more of the following. The first data structure may include database tables, procedure results from logic calls and status/error messages. The second data structure may include an element for each of the application requests and the element may be a class object. 
   In another aspect, the invention features a method including, in a server, receiving a stream of text-based data in an Extensible Markup Language (XML) format, parsing the stream into request statements, and executing each of the request statements. 
   Embodiments may include one or more of the following. Executing may also include intercepting the request statements prior to execution and applying additional logic based on a type or content of the request statements. Executing may also include applying additional logic to responses generated from executing the request statements. 
   The method may also include converting responses generated from each of the executed request statements into an XML format. 
   Embodiments of the invention may have one or more of the following advantages. 
   The method provides a computer software application with the ability to send and receive database requests over any type of computer network to and from multiple databases in a distributed application environment. 
   The method provides a computer software application with the ability to send and receive logic requests over any type of computer network in a distributed application environment, and automatically display, render and/or using the responses to the requests. 
   The method provides a technique for making each request/response sent over the network variable length so that it can contain multiple and different request/responses. 
   The method provides a technique for wrapping requests and responses into a format that is network independent. 
   The method is a technique for formatting data retrieved via a database request or logic call or some other method type in such a way that it can contain multiple records, logic call results and error messages that are easily accessible. 
   The technique provides for nesting or chaining the database and logic call methodology so that when a request is made from a client side of a computer application to a server side of the computer application, the server side can make its own requests and receive responses to other applications and/or databases, independent of their location in the same manner as the client side. 
   The method provides for setting up database relationships for Database Enabled Controls such as, for example, text boxes, drop down boxes, check boxes, and radio buttons, via property settings. 
   The technique allows a developer the ability to manipulate the retrieved data results in a method specific to the retrieved data format. 
   The technique provides for backward compatibility of the request/response structure so that when future request/response structures are added, they do not conflict with earlier versions of the response/request structure. 
   The technique provides for translating the requests into a structure/language understandable by the intended recipients (i.e. database, application logic, etc.). 
   Various programming languages can be used to implement the techniques described herein and accepted programming techniques are utilized in order to increase industry acceptance and maximize the adaptability and flexibility of the techniques. 
   The technique uses structured or modularized programming so that the addition of new functionality, request types, and action types is simplified. 
   The method extends the Server Application Interface to perform future actions not yet developed based on the XML requests passed to it. An example of an action being a “SELECT” statement for a database or an “execute” statement for computer code. 
   The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 

   
     DESCRIPTION OF DRAWINGS 
       FIG. 1  is a block diagram of a distributed application environment. 
       FIG. 2  is a block diagram of a user system. 
       FIG. 3  is a block diagram of a server system. 
       FIG. 4  is a diagram of the application development front-end process. 
       FIG. 5  illustrates a general format of an XML request. 
       FIG. 6  is a diagram of the application development back-end process. 
       FIG. 7  illustrates a general format of an XML response. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a distributed application environment  10  is shown. The environment  10  is a computing environment in which computer software applications are implemented or installed. The environment  10  includes user systems (also referred to as client systems)  12  and  14 . Each of the user systems  12  and  14  is connected to a network of computers such as the Internet  16 . Other networks may include, for example, local area networks (LANs), wide area networks (WANs), intranets, and wireless Internet. A server system  18  and a server system  20  are linked to the Internet  16 . Server systems  18  and  20  are often referred to as application servers or database servers. An example server system is a web server such as an Apache web server (see http://www.apache.org). In general, the servers  18  and  20  each execute a computer program that provides services to other computer programs in the same or other computers, such as user systems  12  and  14 . In a client/server programming model, each of the server systems  18  and  20  executes a program that awaits and fulfills requests from client programs in the same or other computers, such as the user systems  12  and  14 . Fulfillment of a request is generally referred to as a response. 
   In the World Wide Web (“Web”), servers  18  and  20  are generally referred to as Web servers. A Web server uses the client/server programming model and the Web&#39;s Hypertext Transfer Protocol (HTTP) to serve files that form Web pages to Web users on user systems  12  and  14 . The user systems  12  and  14  typically contain HTTP clients that forward the requests to the servers. Popular Web servers are, for example, Microsoft&#39;s Internet Information Server (IIS), which comes with the Windows NT server; Netscape FastTrack and Enterprise servers; and Apache, a Web server for UNIX-based operating systems. Other example Web servers include Novell&#39;s Web Server for users of its NetWare operating system, and IBM&#39;s family of Lotus Domino servers. 
   Referring to  FIG. 2 , each of the user systems, user system  12  for example, includes a computer  40 . The computer  40  is linked to the Internet  16  using TCP/IP (Transmission Control Protocol/Internet Protocol) or another suitable protocol. Computer  40  contains a processor  42 , a memory  44  and an input/output (I/O) interface  46 . Memory  44  stores an operating system (“OS”)  48 , a TCP/IP protocol stack  50  for communicating over network  16  and machine-executable instructions executed by processor  42  to perform an application development front-end process  52 . Computer  40  may also include an input/output (I/O) device  54  linked to the I/O interface  46 . The I/O device  54  may display a graphical user interface (GUI)  56  to a user  58 . In other examples, the user  58  may interact with the I/O device  54  through a non-visual interface such as a programmatic interface (not shown). 
   In general, a GUI  56  is a graphical (rather than purely textual) user interface to a computer. The term came into existence because the first interactive user interfaces to computers were not graphical; they were text-and-keyboard oriented and usually included commands that had to be remembered and computer responses that were infamously brief. Elements of a GUI  56  include such things as: windows, pull-down menus, buttons, scroll bars, iconic images, wizards and the mouse. With the increasing use of multimedia as part of the GUI  56 , sound, voice, motion video, and virtual reality interfaces become part of the GUI  56  for many applications. A system&#39;s graphical user interface (GUI) along with its input devices is sometimes referred to as its “look-and-feel.” When creating an application, many object-oriented tools exist that facilitate writing a graphical user interface. Each GUI element is typically defined as a class widget from which one may create object instances for a specific application. One may code or modify prepackaged methods that an object will use to respond to user stimuli. 
   The GUI  56 , when utilized, has its standard visual controls modified or extended so that the visual controls are “data enabled.” A control is a GUI element such as a Text Field, List Box, Table, or Radio Button. A data enabled control is a standard GUI control that has properties added to it that describes its relationships to tables in a database. A data enabled control has properties describing the data relationships to the control and the locations of data and data sources that pertain to that control. These properties are set by a programmer and can be modified programmatically. Once the controls are extended, the ability to set and change the properties simplifies the process of mapping data to the data enabled controls. The key properties implemented to “data-enable” a control are a location of a database table, a name of the table, and a column name that the control is related to. Other properties may include, but are not limited to, the following information: a listing of table relationships; an indicator if the control is a key column in the table; an indicator if the control is a primary key column and if is part of a compound primary key; an indicator that sets whether the record is locked when in use, and an indicator if the data in the control has changed. 
   A non-visual interface is an interface of an application through which a developer writes computer software code that automatically interacts with other software based on certain pre-determined conditions or events. This computer software code can be either a single program/module or set of modules contained within an application or outside the application but with programmatic access to it. This computer software code is executed behind the scenes and is generally transparent to the user  58  and not requiring user input. 
   When a non-visual interface is incorporated, two types of interfaces may be present: a programmatic data request interface and a custom request interface. The programmatic data request process generates programmatic data request. The custom request interface generates a custom request that includes a stream of data formatted in Extensible Markup Language (XML). 
   XML is a flexible way to generate common information formats and share both the format and the data on the World Wide Web, intranets, and elsewhere. For example, computer makers might agree on a standard or common way to describe the information about a computer product (processor speed, memory size, and so forth) and then describe the product information format with XML. Such a standard way of describing data enables a user to send an intelligent agent (a program) to each computer maker&#39;s Web site, gather data, and then make a valid comparison. XML can be used by any individual or group of individuals or companies that wants to share information in a consistent way. 
   XML, a formal recommendation from the World Wide Web Consortium (W3C), is similar to the language of today&#39;s Web pages, the Hypertext Markup Language (HTML). Both XML and HTML contain markup symbols to describe the contents of a page or file. HTML, however, describes the content of a Web page (mainly text and graphic images) only in terms of how it is to be displayed and interacted with. For example, the letter “p” placed within markup tags starts a new paragraph. XML describes the content in terms of what data is being described. For example, the word “phonenum” placed within markup tags could indicate that the data that followed was a phone number. This means that an XML file can be processed purely as data by a program or it can be stored with similar data on another computer or, like an HTML file, that it can be displayed. For example, depending on how the application in the receiving computer wanted to handle the phone number, it could be stored, displayed, or dialed. 
   XML is “extensible” because, unlike HTML, the markup symbols are unlimited and self-defining. XML is actually a simpler and easier-to-use subset of the Standard Generalized Markup Language (SGML), the standard for how to create a document structure. 
   Referring to  FIG. 3 , each of the server systems, server system  18  for example, includes a computer  70 . The computer  70  is linked to the Internet  16  using TCP/IP (Transmission Control Protocol/Internet Protocol) or another suitable protocol. Computer  70  contains a processor  72 , a memory  74  and an input/output (I/O) interface  76 . Memory  74  stores an operating system (“OS”)  78 , a TCP/IP protocol stack  80  for communicating over network  16  and machine-executable instructions executed by processor  42  to perform an application development back-end process  90 . Computer  40  includes a link  82  to a storage device  84 . The storage device  84  includes one or more databases  86 . 
   Referring to  FIG. 4 , the application development front-end process  52  of  FIG. 2  includes data set object process  100 , a GUI/data set interface process  102 , an XML structure process  104  and an Extensible Markup Language (XML) transmission process  106 . The XML transmission process  106  includes an XML generation subprocess  108  and an XML parser subprocess  110 . The process  52  does not contain the GUI/data set interface process  102  when a non-visual interface is employed in a user system. 
   The data set object process  100  distributes received data into a data structure called a dataset object. The dataset object holds the data used for interacting with the GUI and non-visual interface, the data sources and/or application logic, i.e., the function of the dataset object is to house application data passed back and forth from the application development front-end process  52  and application development back-end process  90 . 
   There are three basic types of information stored in the dataset object, although other types may be added as needed, i.e., information from database tables or record sets, stored procedure results from logic calls and status/error messages. The dataset object is structured in an object-oriented manner so that it is flexible and easily extended for different types of data structures. 
   In other examples, access to the dataset object may be obtained. For example, a subroutine can be written to access the data contained in the dataset object in order to manipulate it as necessary. Also, more than one dataset object may exist in the GUI/data set interface process  102 . 
   The dataset object houses a dataset. The dataset may contain multiple record sets (one for each table/relation in the dataset, logic call or stored procedure results and error or status messages). For each record set in the dataset, there is a corresponding table dictionary or layout that contains a data structure of a database table from which that data comes from and a set of records or rows from a table that contains the actual data that includes fields or columns. The number of fields or columns depends upon the table layout/dictionary. Depending on the data source, the fields may contain data in any format specific to that data source. There can be multiple record sets in a dataset object, each with their own table layout and set of records. The flexible structure of the dataset allows for a user to implement logic that is specific to accessing that particular type of data. This functionality allows for the ability to manipulate any type of data from such varied sources as, for example, relational databases, object databases, LDAP directories and proprietary database formats. 
   In the stored procedure results object, the results of algorithm, subroutine, function, method or other logic calls are stored. The results are written to the dataset in the same structure as the subroutine produced them. 
   In the Status/Error Messages object the results of any status or error messages generated on the application development back-end process  90  are stored. The error messages may come from problems with accessing data in a database, custom generated error messages from validations and various other sources. 
   The dataset object is not limited to the storage of record sets, stored procedure results and status/error messages. The dataset object structure is expandable and new data types may be added in the future as they are developed. As these new data types are developed, the dataset structure can be modified to accommodate the new data required by the new data types. The structuring of the dataset in an object-oriented manner allows for this flexibility and ease of expansion and addition of new types. 
   The GUI/data set interface process  102  provides an interface between controls (not shown) in the GUI  56  and a dataset object. One purpose of the interface process  102  is to keep the controls of the GUI  56  and data in the dataset object process  100  synchronized. The GUI/dataset interface process  102  monitors the data-enabled controls of the GUI  56  for changes/updates. For example, anytime the focus of a control is changed or the “Return/Enter” key is depressed on a keyboard, a value contained in the control is checked against the corresponding piece of data in a dataset object. If the data is different, the dataset object updates its dataset. If the dataset object receives new data and the new data is different the data in the data-enabled controls of the GUI  56 , the GUI/dataset interface process  102  updates the data-enabled GUI controls affected. 
   The GUI/dataset interface process  102  may also contain a series of functions and event triggers that can be accessed/implemented by a programmer to help manipulate the data in the data enabled controls, perform actions, execute application logic or make database calls. Some examples of common functions are: set the value of a control, get the current value of a control and set the focus to a control. Some common examples of event triggers are: a value of a control has changed and the control in focus has changed. 
   A series of functions are used to update and synchronize the data displayed in the data enabled GUI controls and the dataset object as well as trigger execution of some application logic. The programmer implements the event triggers in order to initiate actions or application logic based on certain criteria. Some examples of actions are the retrieving, updating, or deleting of a database record or the execution of some application logic on the application development back-end process  90 . 
   The XML structure process  104  generates an XML structure in response to a request or action received from the data enabled GUI controls or via a programmatic request or action. An XML structure is a variable stream of data stored in memory that includes an XML Element for each request/action submitted. Each XML Element is a class object whose data is stored in such a way to allow easy generation of XML from the data. The delimited data in the XML structure contains parameters/data for carrying out requests/actions on the applications development back-end process  90 . Depending on the request/action, an XML Element may contain data from a dataset object, such as table dictionaries, column names and data from the record sets, stored procedure parameters or other information. 
   The XML generation subprocess  108  in the XML transmission process  106  takes an XML structure from memory  44  and converts the XML structure into a stream of XML data referred to as an XML request by converting the delimiters in the XML structure into XML tags through a standard naming convention based on the delimiter and its location in the data. The XML transmission process  106  sends the XML Request across the network  16  (of  FIG. 1 ) to the application development back-end process  90  using a text transmission protocol such as Hypertext Transfer Protocol (HTTP). Included in the transmitted stream of data are the application server location/name and the application development back-end process  90  so the stream may be routed properly in the event that multiple application development back-end processes are implemented in a single server or multiple servers in the network  10  contain application development back-end processes. 
   Referring to  FIG. 5 , a general format  120  of an XML request is shown. The naming of the tags in  FIG. 5  is arbitrary and may be changed to fit any naming convention. The format  120  is shown with two types of actions or requests, i.e., a stored procedure or program logic call and a database call. The logic call is defined by the &lt;STPROC&gt; . . . &lt;/STPROC&gt; XML identifier tags and the database call is defined by the &lt;REC&gt; . . . &lt;/REC&gt; XML identifier tags. These tags are used for illustration purposes. As long as the structure is maintained, the nomenclature for the XML tags is irrelevant. It is recommended that standard naming convention be adopted for ease of development. 
   The database calls  120  are illustrated with four different variations delimited by the &lt;ReC&gt;&lt;/REC&gt; tags depending on what interaction is needed with the database. This is accomplished by adding a different parameter or action to the initial &lt;REC&gt;&lt;/REC&gt; tags for each request. These parameters are shown as an example, other parameters and tags would be added to define various other database calls required by different databases. The same is true for the stored procedure calls. Additional functionality or access to various programming structures and languages can be gained by changing the parameter types or by adding new tags. This flexible structure allows not only for the expansion of existing requests but also for the addition of new and different requests as newer technology and requirements come to light. For example, as wireless computer devices become more standardized, an additional call type can be added to the XML Request structure for accessing these devices by assigning a new set of XML tags that would be structured toward the devices parameter/data requirements. This new call type would then be added to the XML structure process  104  to execute the requests. 
   Referring to  FIG. 6 , the application development back-end process  90  includes an XML parser process  150 , an execution process  152  and an XML wrapper process  154 . The execution process  152  includes a pre-execution logic subprocess  156  and a post-execution logic subprocess  158 . 
   The XML parser process  150  receives the stream of XML requests and parses the stream into request statements with the proper syntax that the intended database/data source, logic and/or other recipient can understand. The request statements are generated based on the parameters and data contained within the XML stream. As various request types are added, the XML Parser process  150  can be updated to handle the parsing of the new types without disruption. 
   The execution process  152  receives the request statements from the XML parser process  150  in the pre-execution logic subprocess  156 . One function of the execution process  152  is to execute the request statements and receive any responses to those requests. The pre-execution logic subprocess  156  gives the execution process  152  a chance to perform additional logic based on the type or content of the request statements. The request statements can be modified or canceled in the pre-execution logic subprocess  156 . 
   When the pre-execution logic subprocess  156  is complete request statements are executed in the execution process  152  by sending the request statements to the intended database/data source, logic or other recipient. The execution and processing of the request statements may entail data retrieval, manipulation, calculations, and/or execution of additional logic, before a response is returned. There are different methods for executing the statements depending on the request types and the programming languages used. The results of executing the request statements, if any, are returned to the execution process  152  along with any status and/or error messages generated by the requests. 
   The post-execution logic subprocess  158  gives the execution process  152  a chance to perform additional logic based on the type or content of the responses. When the post-execution logic subprocess  158  is complete the responses are sent to the XML wrapper process  154 . 
   The XML Wrapper process  154  takes the responses or results and translates them back into XML in the form of a XML response utilizing a specific XML format. These responses are returned to the application development front-end process  52  across the network  16 . 
   Referring to  FIG. 7 , a general format  170  of an XML response is shown. The naming of the tags in the figure is arbitrary and can be changed to fit any naming convention. The format  170  is shown with four types of responses: error messages, status messages, stored procedures/program logic results and database results. The error messages are defined by the &lt;ERROR&gt; &lt;/ERROR&gt; tags, the status messages are defined by the &lt;STATUS&gt; &lt;/STATUS&gt; tags, the stored procedure results are defined by the &lt;STPROC&gt; &lt;/STPROC&gt; tags, and the database results are defined by the &lt;TBL&gt; &lt;/TBL&gt; tags. 
   Within the main tags are sub-tags. The parameters and tags are arbitrary and used for illustration purposes. As long as the format  170  is maintained, the nomenclature for the XML tags is irrelevant. Other parameters and tags may be added to define various other response types. 
   The XML response is received by the XML parser subprocess  110  of the XML transmission process  106  in the application development front-end process  52 . The XML parser subprocess  110  takes the responses or results and, based on where the original request originated, parses the data out and case inserts the data into the proper dataset of the dataset object. The placement of the data in the dataset is based on the XML tag structure. Based on where the original request originated, the appropriate logic is notified by the dataset object that makes use of the data. If the originator of the request was the GUI  56  then the GUI/dataset interface process  102  evaluates the data in the appropriate dataset object and updates the GUI controls as necessary. 
   A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, a first application development front-end process may interface with one or more other application development front-end processes in a single or multiple servers. This chaining of application development front-end processes provide multiple levels of data and application access and interaction. Accordingly, other embodiments are within the scope of the following claims.