What is new in Version 2.0

The following section details new features and migration information for WebSphere MQ Everyplace version 2.0.

Changes

The following sections give information on new features in WebSphere MQ Everyplace.

Listener architecture

New listener classes have been created that allow the listeners to be managed by WebSphere MQ Everyplace. This means that they can be administered remotely, administered locally, and are persistent in the registry. You no longer have direct access to the implementation classes, but deal with listeners indirectly.

The old listener classes have been deprecated and moved to the deprecated.jar file. The old listeners still work, we strongly discourage you from using them.

Persistence of listeners

Listeners are now persistent in the registry. Once created they exist until removed, even if the queue manager is closed and reopened. This is different from the behaviour in version 1.2.7 and lower versions. If a listener is loaded from the registry at queue manager start-up, the listener starts automatically.

If a new listener is created then it must be explicitly started. All listeners require a name, and this name must be unique within the set of listeners on the same queue manager. This name has no purpose except to distinguish between listeners during administration and during storage in the registry.

Remote administration of listeners

Listeners can be administered by using the new admin message class MQeListenerAdminMessage. All of the local administration actions are available with the exception of check channel timeout.

Message store failure behavior

The behavior of message stores has been changed to throw MQeMessageStoreException when it encounters an irrecoverable situation in the underlying storage media, for example, if a file does not exist when it should, or a file cannot be created or destroyed. Once an MQeMessageStoreException has been thrown, the message store, and hence the queue, cannot be used until it is restarted. However, this should be a rare occurrence, but when it occurs it is serious enough to warrant manual intervention.

Registry

Improvements to the persistent data representation in the registry and the message store means changes in the format of the data. These changes mean that a registry generated under version 1 of WebSphere MQ Everyplace is not acceptable to a queue manager started using Version 2.0 of WebSphere MQ Everyplace. The application generates an exception error to signal this fact. In Java this is com.ibm.mqe.MQeExceptionCodes.Except_QMgr_RegistryDataVersion. If you encounter this exception you will need to migrate the data in the registry. WebSphere MQ Everyplace provides classes to perform this migration. The required classes are in the package com.ibm.mqe.validation, and the only public class is com.ibm.mqe.validation.MQeDiskImageValidator. An example of how to use this class to perform migration is provided in examples.migration.Migrator.

Enhancements

WebSphere MQ Everyplace version 2.0 includes many new features. It now supports even more platforms including Windows XP. There are more programming options available through the introduction of a new native C language implementation for Microsoft Pocket PC. It also supports point-to-point messaging using the Java Message Service (JMS), an integral part of Java 2 Platform, Enterprise Edition (J2EE) technology that improves programmer productivity by defining a common set of messaging concepts and programming strategies.

A subset of WebSphere MQ Everyplace now also runs on the Java 2 Platform, Micro Edition (J2ME) technology, which covers a range of smaller devices such as smart cards, pagers and small PDAs. These and many other enhancements in WebSphere MQ Everyplace 2.0 are listed below:

If you are migrating from earlier versions of WebSphere MQ Everyplace we strongly recommend that you read the migration section of this book and the WebSphere MQ Everyplace Application Programming Guide for details of changes.



© IBM Corporation 2002. All Rights Reserved