= Changing JMS Implementations
:index-group: Configuration
:jbake-date: 2018-12-05
:jbake-type: page
:jbake-status: published

NOTE: Licensed to the Apache Software
Foundation (ASF) under one or more contributor license agreements. See
the NOTICE file distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file to you under
the Apache License, Version 2.0 (the "License"); you may not use this
file except in compliance with the License. You may obtain a copy of the
License at . http://www.apache.org/licenses/LICENSE-2.0 . Unless
required by applicable law or agreed to in writing, software distributed
under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
OR CONDITIONS OF ANY KIND, either express or implied. See the License
for the specific language governing permissions and limitations under
the License.

ActiveMQ is the default JMS provider in Apache TomEE and OpenEJB.

Changing JMS implementation is as simple as using that implementation's
Java EE Connector. The connector which will be a `.rar` file should be
bundled with the application in a `.ear` file. All JMS usage in that
`.ear` will favor the JMS ConnectionFactory and Topic and Queue
implementations that are configured in the `.rar` file rather than
ActiveMQ.

If the JMS implementation does not have a `.rar` file, there are still
some options for wiring in an alternate implementation.

== Generic JMS Resource Adapter

If the JMS implementation does not have a Resource Archive (`.rar` file)
that defines a compliant Resource Adapter, the
http://genericjmsra.java.net/[Generic Resource Adapter for JMS] should
work fine.

To use this Adapter in TomEE or OpenEJB you'll need to create a
`service-jar.xml` file and include that in a jar file and add it to the
`<tomee.home>/lib/` directory. Then you can declare `ConnectionFactory`,
`Topic`, and `Queue` and more via the `tomee.xml` file.

The one below should be considered boiler plate. Updating it to contain
some useful default values for your JMS implementation would be good.
These values can be overridden in the `tomee.xml` or `openejb.xml`

Let's say that the following file lives in the jar at
`META-INF/org.superbiz/service-jar.xml`

[source,xml]
----
<?xml version="1.0" encoding="UTF-8"?>
<ServiceJar>
  <ServiceProvider
      id="genericra"
      service="Resource"
      types="GenericJMSRA"
      class-name="com.sun.genericra.GenericJMSRA">
          UserName
          Password
          ProviderIntegrationMode
          ConnectionFactoryClassName
          QueueConnectionFactoryClassName
          TopicConnectionFactoryClassName
          XAConnectionFactoryClassName
          XAQueueConnectionFactoryClassName
          XATopicConnectionFactoryClassName
          UnifiedDestinationClassName
          TopicClassName
          QueueClassName
          SupportsXA
          ConnectionFactoryProperties
          JndiProperties
          CommonSetterMethodName
          RMPolicy
          LogLevel
          DeliveryType
          UseFirstXAForRedelivery
  </ServiceProvider>

  <ServiceProvider
      id="ConnectionFactory"
      service="Resource"
      types="jakarta.jms.ConnectionFactory, jakarta.jms.QueueConnectionFactory, jakarta.jms.TopicConnectionFactory, QueueConnectionFactory, TopicConnectionFactory"
      class-name="com.sun.genericra.outbound.ManagedJMSConnectionFactory">
          ConnectionFactoryJndiName
          ClientId
          ConnectionValidationEnabled
          ResourceAdapter
  </ServiceProvider>

  <ServiceProvider
      id="Queue"
      service="Resource"
      types="jakarta.jms.Queue, Queue"
      class-name="com.sun.genericra.outbound.QueueProxy">
          DestinationJndiName
          ResourceAdapter
          UserName
          Password
          JndiProperties
          QueueClassName
  </ServiceProvider>

  <ServiceProvider
      id="Topic"
      service="Resource"
      types="jakarta.jms.Topic, Topic"
      class-name="com.sun.genericra.outbound.TopicProxy">
          DestinationJndiName
          ResourceAdapter
          UserName
          Password
          JndiProperties
          TopicClassName
  </ServiceProvider>
</ServiceJar>
----

It is strongly recommended to not leave the values in the
service-jar.xml file blank as shown above. It is possible to set up
several sets of defaults in a `service-jar.xml` or via several
`service-jar.xml` files.

Once this file is packed in a jar and added to the `<tomee.home>/lib` or
`<openejb.home>/lib` directory, you can then declare and configure
"instances" of these things in your `tomee.xml` or `openejb.xml` config
file as follows:

[source,xml]
----
<Resource id="My Generic Adapter" type="GenericJMSRA" provider="org.superbiz:genericra">
AdapterProperty1 PropertyValue1
AdapterProperty2 PropertyValue2
...
</Resource>
----

Or in properties like so:

[source,properties]
----
myGenericAdapter = new://Resource?type=GenericJMSRA&provider=org.superbiz:genericra
myGenericAdapter.AdapterProperty1 = PropertyValue1
myGenericAdapter.AdapterProperty2 = PropertyValue2
----

This is basically the same as all configuration in TomEE/OpenEJB, but
with the addition that you must specify the `provider` attribute so the
server knows where to look for the `service-jar.xml` file that defines
the resource and all its defaults.

In this example:

* the file is `META-INF/org.superbiz/service-jar.xml`
* so the `provider` attribute is `org.superbiz`

You can use whatever prefix you like for the `provider` id, though for
obvious reasons we'd advise not using `org.apache.openejb` or
`org.apache.tomee` in the prefix.
