Implementing request/reply programming semantics using publish/subscribe middleware

Abstract

A request/reply middleware wrapper that transposes an application's request/reply communications into publish/subscribe communications implemented by publish/subscribe middleware where every distributed application component of a distributed application is referenced by a component type and name. Each component type has associated with it a request publish/subscribe topic and a reply publish/subscribe topic. Each distributed application component subscribes to its request and reply topics and can publish to request and reply topics of other component types. By utilizing callback objects, the middleware wrapper facilitates the transmission of a request and replies between distributed application components by posting the requests or replies on an appropriate request or reply publish/subscribe topic.

1 . A computer system for communicating messages between components of a distributed application, the computer system comprising a plurality of communicating computing devices embodied with computer logic that:
 receives a message formulated according to request/reply semantics from a first distributed application component, wherein the message identifies a second distributed application component;   in response to receiving the message:
 publishes the message to a publish/subscribe topic; and 
   in response to publishing the message to the topic:
 sends the message to the second distributed application component. 
   
     
     
         2 . The computer system of  claim 1 , wherein said message is a request or reply. 
     
     
         3 . The computer system of  claim 1 , wherein the publish/subscribe topic is identified based on a property of the second distributed application component. 
     
     
         4 . A method of communicating messages between components of a distributed application, the method implemented in a computer system comprising a plurality of communicating computing devices, the method comprising:
 receiving in the computer system a message formulated according to request/reply semantics from a first distributed application component, wherein the message identifies a second distributed application component;   
       in response to receiving the message:
 publishing in the computer system the message to a publish/subscribe topic; and 
 
       in response to said publishing the message to the topic:
 sending the message to the second distributed application component. 
 
     
     
         5 . The method of  claim 4 , wherein said message is a request or reply. 
     
     
         6 . The method of  claim 4 , wherein the publish/subscribe topic is identified based on a property of the second distributed application component.