Creating proxies for distributed beans and event objects

• US 6,230,160 B1
• Filed: 07/16/1998
• Issued: 05/08/2001
• Est. Priority Date: 07/17/1997
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Yu, Paul Kwong-Hung, Chan, Victor Shih-Chuan
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): JUNG, DAVID YIUK
• Application Number:
  US09/116,836
• Time in Patent Office: 1,027 Days
• Field of Search: 707/100-104, 707/200-206, 707/3-6, 707/7-10, 709/315, 709/201-223
• US Class Current: 1/1
• CPC Class Codes: G06F 9/548 Object oriented; Remote method invocation [RMI] non-remote method invocation G06F9/449
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99946 Object-oriented database structure network

Abstract

The invention provides a mechanism for distributing objects from a object oriented framework that permits method invocation and state information notification, such as event notification in a JavaBeans software component model. A code generation tool generates code from an existing server object that contains only application domain specific logic, to support deployment of the server object on a remote machine in a distributed application. The generated code includes a proxy class to reside locally with a client program that might invoke methods on the server object or receive notification of state information (events) from the server object, and a proxy class to be remotely deployed with the server object. The proxies created provide all the middleware specific logics. More importantly, the proxy on the client side contains all of the public methods, properties and event interfaces of the server object, so that a client program using this proxy can invoke the server object'"'"'s methods and register to receive notification of state information on the proxy as if it were interacting locally with the server object. A proxy on the server side communicates the client program'"'"'s method invocations and registrations to receive event notifications to the server object as if this proxy were a local client. When an event notification is issued by the server object, it is received by the proxy on the client side which transmits the notification through the middleware of the distributed application to the proxy on the client side. The proxy on the client side overrides the identification of the source of the notification, substituting itself, to receive any requests for data on the state information from the client program, but then delegates such requests to the object containing the state information to be fulfilled.

Claims

1. In a distributed object oriented programming environment, a mechanism to provide access to a server object in a first domain containing domain-specific logic for remote method invocations and state information notifications, comprising:

a first proxy located in the first domain having middleware-specific logic to transmit and receive method invocations and state information notifications over the distributed environment, and an interface to interact with the server object as a local client program;

a second proxy located in a remote domain with a client program, the second proxy having middleware-specific logic to transmit method invocations and receive state information notifications over the distributed environment, and having an interface to interact with the client program as a local server object, means to instantiate a proxy object in the second proxy for an instance of state information notification received from the server object through the first proxy and the middleware, said proxy object identifying the second proxy as source of the instance of state information notification; and

means to transmit the proxy object to the client program.

2. The mechanism, according to claim 1, wherein the second proxy has interfaces identical to interfaces in the server object, whereby the client program interacts with the second proxy as a local copy of the server object.

3. The mechanism, according to claim 1, wherein the means to instantiate the proxy object further include means to generate a delegate in the proxy object to the instance of state information, whereby the proxy object provides an interface for requests from the client program for data on the instance and responses from the instance to said requests.

4. A code generation tool for generating proxy classes from a domains-specific server object for remote method invocation on the server object and communication of state information from the server object over a distributed object oriented application, the code generation tool being adapted to generate:

an event proxy for each item of state information communicable by the server object;

a first proxy for deployment with the server object and adapted to provide a communication interface for method invocations from remote clients on the server object and for state information communications from the server object to communications middleware in the distributed object oriented application; and

a second proxy for deployment with a client program remotely from the server object, and adapted to;

(a) provide a communications interface for method invocations on remote servers from the client program to the communications middleware,

(b) instantiate an event proxy object from the event proxy for each item of state information communicated from the server object through the first proxy, and

(c) communicating the event proxy object to the client program.

5. The code generation tool, according to claim 4, adapted to generate the event proxy as further including means to create a delegation service from the event proxy object instantiated by the second proxy to the item of state information, whereby data on the state information item requested by the client program can be retrieved.

6. The code generation tool, according to claim 4, adapted to generate the second proxy with interfaces identical to the server object.