Using the Java Messaging System

CXF provides a transport plug-in that enables endpoints to use Java Messaging System (JMS) queues and topics. CXF's JMS transport plug-in uses the Java Naming and Directory Interface (JNDI) to locate and obtain references to the JMS provider that brokers for the JMS destinations. Once CXF has established a connection to a JMS provider, CXF supports the passing of messages packaged as either a JMS ObjectMessage or a JMS TextMessage.

JMS Namespaces

WSDL Namespace

The WSDL extensions for defining a JMS endpoint are defined in the namespace http://cxf.apache.org/transports/jms. In order to use the JMS extensions you will need to add the namespace definition shown below to the definitions element of your contract.

xmlns:jms="http://cxf.apache.org/transports/jms"

Configuration Namespaces

In order to use the JMS configuration properties you will need to add the lines shown below to the beans element of your configuration.

xmlns:jms="http://cxf.apache.org/transports/jms"

Basic Endpoint Configuration

JMS endpoints need to know certain basic information about how to establish a connection to the proper destination. This information can be provided in one of two places: WSDL or XML configuration. The following configuration elements which are described can be used in both the client side Conduits and the server side Destinations.

Using WSDL

The JMS destination information is provided using the jms:address element and its child, the jms:JMSNamingProperties element. The jms:address element's attributes specify the information needed to identify the JMS broker and the destination. The jms:JMSNamingProperties element specifies the Java properties used to connect to the JNDI service.

The address element

The basic configuration for a JMS endpoint is done by using a jms:address element as the child of your service's port element. The jms:address element uses the attributes described below to configure the connection to the JMS broker.

The JMSNamingProperties element

To increase interoperability with JMS and JNDI providers, the jms:address element has a child element, jms:JMSNamingProperties, that allows you to specify the values used to populate the properties used when connecting to the JNDI provider. The jms:JMSNamingProperties element has two attributes: name and value. The name attribute specifies the name of the property to set. The value attribute specifies the value for the specified property. The jms:JMSNamingProperties element can also be used for specification of provider specific properties.
The following is a list of common JNDI properties that can be set:

1. java.naming.factory.initial
2. java.naming.provider.url
3. java.naming.factory.object
4. java.naming.factory.state
5. java.naming.factory.url.pkgs
6. java.naming.dns.url
7. java.naming.authoritative
8. java.naming.batchsize
9. java.naming.referral
10. java.naming.security.protocol
11. java.naming.security.authentication
12. java.naming.security.principal
13. java.naming.security.credentials
14. java.naming.language
15. java.naming.applet

For more details on what information to use in these attributes, check your JNDI provider's documentation and consult the Java API reference material.

Using a named reply destination

By default, CXF endpoints using JMS create a temporary queue for sending replies back and forth. You can change this behavior by setting the jndiReplyDestinationName attribute in the endpoint's contract. A client endpoint will listen for replies on the specified destination and it will specify the value of the attribute in the ReplyTo field of all outgoing requests. A service endpoint will use the value of the jndiReplyDestinationName attribute as the location for placing replies if there is no destination specified in the request's ReplyTo field.
The following example shows an example of a JMS WSDL port specification.

<service name="JMSService">
  <port binding="tns:Greeter_SOAPBinding" name="SoapPort">
    <jms:address jndiConnectionFactoryName="ConnectionFactory"
                 jndiDestinationName="dynamicQueues/test.cxf.jmstransport">
      <jms:JMSNamingProperty name="java.naming.factory.initial"
                             value="org.activemq.jndi.ActiveMQInitialContextFactory" />
      <jms:JMSNamingProperty name="java.naming.provider.url"
                             value="tcp://localhost:61616" />
    </jms:address>
  </port>
</service>

Using Configuration

In addition to using the WSDL file to specify the connection information for a JMS endpoint, you can also supply it in the endpoint's XML configuration. The information in the configuration file will override the information in the endpoint's WSDL file.

The addressPolicy property

JMS connection information is specified using the addressPolicy property. The addressPolicy property has a single value: jms:address. It is identical to the jms:address element used in the WSDL file. Like the jms:address element in the WSDL file, the jms:address configuration element also has a jms:JMSNamingProperties child element that is used to specify additional information used to connect to a JNDI provider. The following example shows a CXF configuration entry for configuring the addressing information for a JMS consumer endpoint.

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:ct="http://cxf.apache.org/configuration/types"
       xmlns:jms="http://cxf.apache.org/transports/jms"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<jms:conduit id="{http://cxf.apache.org/jms_endpt}HelloWorldJMSPort.jms-conduit">
  <jms:address destinationStyle="queue"
               jndiConnectionFactoryName="myConnectionFactory"
               jndiDestinationName="myDestination"
               jndiReplyDestinationName="myReplyDestination"
               connectionUserName="testUser"
               connectionPassword="testPassword">
    <jms:JMSNamingProperty name="java.naming.factory.initial"
                           value="org.apache.cxf.transport.jms.MyInitialContextFactory"/>
    <jms:JMSNamingProperty name="java.naming.provider.url"
                           value="tcp://localhost:61616"/>
  </jms:address>
</jms:conduit>
</beans>

The jms:address may also be used inside a jms:destination as well (see below).

Consumer Endpoint Configuration

JMS consumer endpoints specify the type of messages they use. JMS consumer endpoint can use either a JMS ObjectMessage or a JMS TextMessage. When using an ObjectMessage the consumer endpoint uses a byte[] as the method for storing data into and retrieving data from the JMS message body. When messages are sent, the message data, including any formating information, is packaged into a byte[] and placed into the JMS message body before it is placed on the wire. When messages are received, the consumer endpoint will attempt to unmarshall the data stored in the JMS body as if it were packed in a byte[].

When using a TextMessage, the consumer endpoint uses a string as the method for storing and retrieving data from the JMS message body. When messages are sent, the message information, including any format-specific information, is converted into a string and placed into the JMS message body. When messages are received the consumer endpoint will attempt to unmashall the data stored in the JMS message body as if it were packed into a string.

When native JMS applications interact with CXF consumers, the JMS application is responsible for interpreting the message and the formatting information. For example, if the CXF contract specifies that the binding used for a JMS endpoint is SOAP, and the messages are packaged as TextMessage, the receiving JMS application will get a text message containing all of the SOAP envelope information.

Consumer endpoint can be configured by both XML configuration and via WSDL.

Using Configuration

Specifying the message type

You can specify the message type supported by the consumer endpoint using jms:client element that has a single attribute:

• messageType – Specifies how the message data will be packaged as a JMS message. text specifies that the data will be packaged as a TextMessage. binary specifies that the data will be packaged as an ObjectMessage.

The following example shows a configuration entry for configuring a JMS consumer endpoint.

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:ct="http://cxf.apache.org/configuration/types"
       xmlns:jms="http://cxf.apache.org/transports/jms"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
...
<jms:conduit id="{http://cxf.apache.org/jms_endpt}HelloWorldJMSPort.jms-conduit">
  <jms:client messageType="binary"/>
...
</jms:conduit>
...
</beans>

The id on the jms:conduit is in the form of {WSDLNamespace}WSDLPortName.jms-conduit. This provides CXF with the information so that it can associate the configuration with your service's endpoint.

Using WSDL

The type of messages accepted by a JMS consumer endpoint is configured using the optional jms:client element. The jms:client element is a child of the WSDL port element and has one attribute:

• messageType – Specifies how the message data will be packaged as a JMS message. text specifies that the data will be packaged as a TextMessage. binary specifies that the data will be packaged as an ObjectMessage.

Service Endpoint Configuration

JMS service endpoints have a number of behaviors that are configurable in the contract. These include:

• how messages are correlated
• the use of durable subscriptions
• if the service uses local JMS transactions
• the message selectors used by the endpoint

Service endpoints can be configure in one of two ways:

• Configuration
• WSDL

Using Configuration

Specifying configuration data

Using the jms:destination element you can configure your service's endpoint to use JMS. You can specify the service endpoint's behaviors using the server property. It has a single element, jms:server, that has a the following attributes:

The following example shows a CXF configuration entry for configuring a JMS service endpoint.

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:ct="http://cxf.apache.org/configuration/types"
       xmlns:jms="http://cxf.apache.org/transports/jms"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
...
<jms:destination id="{http://cxf.apache.org/jms_endpt}HelloWorldJMSPort.jms-destination">
  <jms:server messageSelector="cxf_message_selector"
              useMessageIDAsCorrelationID="true"
              transactional="true"
              durableSubscriberName="cxf_subscriber" />
</bean>
...
</beans>

Adding address information

The jms:address described above can also be embedded in the jms:destination:

<jms:destination id="{http://cxf.apache.org/jms_endpt}HelloWorldJMSPort.jms-destination">
  <jms:address .../>
  <jms:server .../>
</bean>

Using WSDL

Service endpoint behaviors are configured using the optional jms:server element. The jms:server element is a child of the WSDL port element and has the following attributes:

JMS Runtime Configuration

In addition to configuring the externally visible aspects of your JMS endpoint, you can also configure aspects of its internal runtime behavior. There are three types of runtime configuration:

• Session pool configuration (common to both services and consumers)
• Consumer specific configuration
• Service specific configuration

Session Pool Configuration

You configure an endpoint's JMS session pool using the sessionPoolConfig property. This property allows you to set a high and low water mark for the number of JMS sessions an endpoint will keep pooled. The endpoint is guaranteed to maintain a pool of sessions equal to the low water mark and to never pool more sessions than specified by the high water mark.
The sessionPool property takes a single jms:sessionPool element. The jms:sessionPool element's attributes, listed below, specify the high and low water marks for the endpoint's JMS session pool.

The following example shows an example of configuring the session pool for a CXF JMS service endpoint.

<jms:destination id="{http://cxf.apache.org/jms_endpit}HelloWorldJMSPort.jms-destination">
...
  <jms:sessionPool lowWaterMark="10" highWaterMark="5000" />
</jms:destination>

The jms:sessionPool element can also be used within a jms:conduit.

Consumer Specific Runtime Configuration

The JMS consumer configuration allows you to specify two runtime behaviors:

• the number of milliseconds the consumer will wait for a response.
• the number of milliseconds a request will exist before the JMS broker can remove it.

You use the clientConfig property to set JMS consumer runtime behavior. This property has a single element called jms-conf:clientConfig. This element's attributes, listed in the following table, specify the configuration values for consumer runtime behavior.

The following example shows a configuraiton fragment that sets the consumer endpoint's request lifetime to 500 milliseconds and its timeout value to 500 milliseconds.

<jms:conduit id="{http://cxf.apache.org/jms_endpt}HelloWorldJMSPort.jms-conduit">
...
  <jms:runtimePolicy clientReceiveTimeout="500"
                          messageTimeToLive="500" />
</jms:conduit>

Service Specific Runtime Configuration

The JMS service configuration allows you to specify to runtime behaviors:

• the amount of time a response message can remain unreceived be fore the JMS broker can delete it.
• the client identifier used when creating and accessing durable subscriptions.

The serverConfig property is used to specify the service runtime configuration. It takes a single jms-conf:serverConfig element. This element's attributes, listed below, specify the configuration values that control the service's runtime behavior.

The following example shows a configuration fragment that sets the service endpoint's response lifetime to 500 milliseconds and its durable subscription client identifier to jms-test-id.

<jms:destination id="{http://cxf.apache.org/jms_endpt}HelloWorldJMSPort.jms-destination">
  <jms:runtimePolicy messageTimeToLive="500"
                      durableSubscriptionClientId="jms-test-id" />
</jms:destination>