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A mechanism for handling late replies to messages in an application server

IP.com Disclosure Number: IPCOM000016050D
Original Publication Date: 2002-Jul-14
Included in the Prior Art Database: 2003-Jun-21
Document File: 3 page(s) / 50K

Publishing Venue

IBM

Abstract

Disclosed is a method for handling late replies to messages within an application server. The following diagram shows a scenario where an application bean uses a sender bean to handle the sending of a message, and a receiver bean (MDB) to handle the inbound message.

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A mechanism for handling late replies to messages in an application server

Disclosed is a method for handling late replies to messages within an application server. The following diagram shows a scenario where an application bean uses a sender bean to handle the sending of a message, and a receiver bean (MDB) to handle the inbound message.

  The requesting bean in Application1 (Appl Bean 1) can handle replies by one of two techniques, that is, a Synchronous Mode where the senderBean waits for the reply, or a Deferred Mode, where Appl Bean 1 can inquire of the senderBean as to whether the reply has been received. In either mode a problem arises when the expected reply does not arrive in time for Appl bean 1 to process it. Such a "late reply" may occur for a number of reasons, such as, the application system which is producing the reply message is too busy and cannot reply in time, or because of a failure in the messaging system infrastructure. In these situations the application requiring the reply has to decide what action to take to recover from the error.

  This disclosure describes a method whereby the system can identify the arrival of a "late reply", and deliver it to a predefined application bean to handle. This application bean is implemented as a message-driven bean (MDB) or receiverBean (specialized MDB). Simply, the application waiting for the reply requests the messaging service handles the "late reply". When the message is delivered to the system a listener retrieves the message and passes it to the application MDB for processing.

  The first part of this disclosure describes how the late message condition is recognized and registered. It is enabled within the Application and the senderBean which is sending the message and handling the reply. When the senderBean is deployed the deployer may indicate the bean method is interested in the system handling any reply which is identified as being late. When the application bean is invoked it can handle replies from messages in two modes.

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    In Synchronous Mode the senderBean waits for the reply to be returned. If a time-out occurs while waiting for the reply, and the bean has been deployed with the handle late message function enabled, then a request is logged to an outstanding response log together with the correlation information for the reply. This requires no action on the part of the application, other than to be deployed with the handle late message function enabled. In Deferred Mode the senderBean sends the message and returns to the application bean. It is then the responsibility of the application bean to request the reply. Whe...