Chapter 1. Introduction to the FUSE ESB JMS Binding Component

The JMS binding component allows you to create endpoints that interact with JMS destinations outside of the FUSE ESB's runtime environment. It provides a robust and highly configurable means to interact with JMS systems.

Overview

The FUSE ESB JMS binding component is built on top of the Spring 2.0 JMS framework. It allows you to create two types of endpoints:

Consumer Endpoints: A Consumer endpoint's primary roll is to listen for messages on an extrenal JMS destination and pass them into to the NMR for delivery to endpoints inside of the FUSE ESB container. Consumer endpoints can send responses if one is required.
Provider Endpoints: A Provider endpoint's primary roll is to take messages from the NMR and send them to an external JMS destination.

	Note
	The JMS binding component also supports non-Spring based endpoints. However, the non-Spring based endpoints are deprecated.

In most instances, you do not need to write any Java code to create endpoints. All of the configuration is done using Spring XML that is placed in an xbean.xml file. There are some instances where you will need to develop your own Java classes to supplement the basic functionality provided by the binding components default implementations. These cases are discussed at the end of this guide.

Key features

The FUSE ESB JMS binding component provides a number of enterprise quality features including:

Support for JMS 1.0.2 and JMS 1.1
JMS transactions
XA transactions
Support of all MEP patterns
SOAP support
MIME support
Customizable message marshaling

Contents of a JMS service unit

A service unit that configures the JMS binding component will contain two artifacts:

xbean.xml

The xbean.xml file contains the XML configuration for the endpoint defined by the service unit. The contents of this file are the focus of this guide.

	Note
	The service unit can define more than one endpoint.

meta-inf/jbi.xml

The jbi.xml file is the JBI descriptor for the service unit. Example 1.1 shows a JBI descriptor for a JMS service unit.

Example 1.1. JBI Descriptor for a JMS Service Unit

<jbi xmlns="http://java.sun.com/xml/ns/jbi" version="1.0">
  <services binding-component="false" 
            xmlns:b="http://servicemix.apache.org/samples/bridge"> 
    <provides service-name="b:jms" 
              endpoint-name="endpoint"/> 
    <consumes interface-name="b:MyConsumerInterface"/>  
  </services>
</jbi>

The elements shown in Example 1.1 can be explained as follows:

The service element is required by the JBI specification and is the root element of all service unit descriptors. The value of the binding-component attribute is always false.

The service element contains namespace references for all of the namespaces defined in the xbean.xml file's bean element.

The provides element corresponds to a JMS provider endpoint. The service-name attribute derives its value from the service attribute in the JMS provider's configuration.

	Note
	This attribute can also appear on a `consumes` element.

The endpoint-name attribute derives its value from the endpoint attribute in the JMS provider's configuration.

	Note
	This attribute can also appear on a `consumes` element.

The consumes element corresponds to a JMS consumer endpoint. The interface-name attribute derives its value from the interfaceName attribute in the JMS consumer's configuration.

	Note
	This attribute can also appear on a `provides` element.

Using the Maven JBI tooling

The FUSE ESB Maven tooling provides two archetypes for seeding a project whose result is a service unit for the JMS binding component:

servicemix-jms-consumer-endpoint

The servicemix-jms-consumer-endpoint archetype creates a project that results in a service unit that configures a JMS consumer endpoint.

	Tip
	You can use the smx-arch command to in place of typing the entire Maven command. smx-arch su jms-consumer ["-DgroupId=`my.group.id`"] ["-DartifactId=`my.artifact.id`"]

servicemix-jms-provider-endpoint

The servicemix-jms-provider-endpoint archetype creates a project that results in a service unit that configures a JMS provider endpoint.

	Tip
	You can use the smx-arch command to in place of typing the entire Maven command. smx-arch su jms-provider ["-DgroupId=`my.group.id`"] ["-DartifactId=`my.artifact.id`"]

The resulting project will contain two generated artifacts:

a pom.xml file containing the metadata needed to generate and package the service unit

a src/main/resources/xbean.xml file containing the configuration for the endpoint.

	Important
	The endpoint configuration generated by the archetype is for the deprecated JMS endpoints. While this configuration will work, it is not recommended for new projects and is not covered in this guide.

If you wanted to add custom marshalers, custom destination choosers, or other custom Java code, you would need to add a java folder to the generated src folder. You would also need to modify the generated pom.xml file to compile the code and package it with the service unit.

OSGi Packaging

You can package JMS endpoints in an OSGi bundle. To do so you need to make two minor changes:

you will need to include an OSGi bundle manifest in the META-INF folder of the bundle.
You need to add the following to your service unit's configuration file:
```
<bean class="org.apache.servicemix.common.osgi.EndpointExporter" />
```

	Important
	When you deploy JMS endpoints in an OSGi bundle, the resulting endpoints are deployed as a JBI service unit.

For more information on using the OSGi packaging see Appendix D.

Namespace

The elements used to configure JMS endpoints are defined in the http://servicemix.apache.org/jms/1.0 namespace. You will need to add a namespace declaration similar to the one in Example 1.2 to your xbeans.xml file's beans element.

Example 1.2. Namespace Declaration for Using JMS Endpoints

<beans ...
      xmlns:jms="http://servicemix.apache.org/jms/1.0"
      ... >
  ...
</beans>

In addition, you need to add the schema location to the Spring beans element's xsi:schemaLocation as shown in Example 1.3.

Example 1.3. Schema Location for Using JMS Endpoints

<beans ...
       xsi:schemaLocation="...
http://servicemix.apache.org/jms/1.0 http://servicemix.apache.org/jms/1.0/servicemix-jms.xsd
...">
  ...
</beans>