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Example: Publishing a WS-Notification message

Use this task to write the code for a publisher client application that can publish a notification message to a broker, based on the example code extract provided.

This example is based on using the Java API for XML-based remote procedure calls (JAX-RPC) APIs with code generated using the WSDL2Java tool (run against the Notification Broker WSDL generated as a result of creating the WS-Notification service point) and WebSphere Application Server APIs and SPIs.

In WebSphere Application Server there are two implementations of the WS-Notification service: Version 6.1 and Version 7.0. This JAX-RPC example can interact successfully with Version 6.1 or Version 7.0 WS-Notification service points. However to use WS-Notification with policy sets, for example to enable composition with WS-ReliableMessaging, then the WS-Notification applications must be encoded to use the Java API for XML-based Web Services (JAX-WS) programming model and must interact with Version 7.0 WS-Notification service points. If we are new to programming JAX-WS client applications, see the following topics:

The article Writing JAX-WS applications for WS-Notification includes an example of a JAX-WS publisher client application.

To write the code for a publisher client application that can publish a notification message to a broker... referring to the example code extract for further information.

  1. Look up the JAX-RPC service. The JNDI name is specific to the web services client implementation.

  2. Get a stub for the port on which to invoke operations.

  3. Create the message contents for a notification message.

  4. Create a notification message from the contents.

  5. Add a topic expression to the notification message. The topic expression must indicate to which topic or topics the message corresponds.

  6. Create any optional information.

  7. Optional: If the broker requires publisher client applications to register, associate the request with a particular publisher registration. The registrationEPR is the ConsumerReference EndpointReference returned by the broker in relation to an invocation of the RegisterPublisher operation.

  8. Invoke the Notify operation by calling the associated method on the stub.


Example

The following example code represents a publisher client application that can publish a notification message to a broker: 

// Look up the JAX-RPC service. The JNDI name is specific to the web services client implementation InitialContext context = new InitialContext();
javax.xml.rpc.Service service = (javax.xml.rpc.Service) context.lookup(
    "java:comp/env/services/NotificationBroker");

// Get a stub for the port on which to invoke operations NotificationBroker stub = (NotificationBroker) service.getPort(NotificationBroker.class);

// Create the message contents for a notification message
SOAPElement messageContents = null;
javax.xml.soap.SOAPFactory soapFactory = javax.xml.soap.SOAPFactory.newInstance();
if (soapFactory instanceof IBMSOAPFactory) {
    // We can use the value add methods provided by the IBMSOAPFactory API to create the SOAPElement
    // from an XML string.
    String messageContentsXML = "<xyz:MyData xmlns:xyz=\"uri:mynamespace\">Some data</xyz:MyData>";        
    messageContents = ((IBMSOAPFactory) soapFactory).createElementFromXMLString(messageContentsXML);
} else {
    // Build up the SOAPElement using the standard javax.xml.soap APIs     messageContents = soapFactory.createElement("MyData", "xyz", "uri:mynamespace");
    messageContents.addTextNode("Some data");
}

// Create a notification message from the contents
NotificationMessage message = new NotificationMessage(messageContents);               

// Add a topic expression to the notification message indicating to which topic or topics the // message corresponds
Map prefixMappings = new HashMap();
prefixMappings.put("abc", "uri:example");
TopicExpression exp = 
    new TopicExpression(TopicExpression.SIMPLE_TOPIC_EXPRESSION, "abc:ExampleTopic", prefixMappings);        
message.setTopic(exp);

// Create any optional information
SOAPElement[] optionalInformation =  new SOAPElement[] {};
        
/*
Optional --------
The following line will cause the request to be associated with a particular publisher registration.
We must do this if the broker requires publishers to register. The registrationEPR is the ConsumerReference EndpointReference returned by the broker in relation to an invocation of the 
RegisterPublisher operation.
        
    ((Stub) stub)._setProperty(WSAConstants.WSADDRESSING_DESTINATION_EPR, consumerReferenceEPR);
*/

// Invoke the Notify operation by calling the associated method on the stub
stub.notify(new NotificationMessage[] { message }, optionalInformation);


Related concepts

  • JAX-RPC
  • Brokered notification

  • JAX-RPC

  • WS-Notification


    Related tasks

  • Writing a WS-Notification application that exposes a web service endpoint

  • Writing a WS-Notification application that does not expose a web service endpoint

  • Filtering the message content of publications

  • Example: Subscribing a WS-Notification consumer

  • Example: Pausing a WS-Notification subscription

  • Example: Create a WS-Notification pull point

  • Example: Getting messages from a WS-Notification pull point

  • Example: Registering a WS-Notification publisher

  • Example: Create a Notification consumer web service skeleton

  • Use WS-Notification for publish and subscribe messaging for web services

  • Secure WS-Notification

  • WSDL2Java command for JAX-RPC applications

  • WSDL2Java command for JAX-RPC applications

  • WS-Notification troubleshooting tips
    WS-BrokeredNotification Version 1.3 OASIS Standard
    Writing JAX-WS applications for WS-Notification