Creating a user-defined JMS data binding

A user-defined JMS data binding is necessary when the JMS client is expecting a Enterprise JavaBeans (EJB) and the SCA application is expecting business objects.

public class BookObject implements java.io.Serializable {

	private String ISDN;

	private String author;

	private String title;

	private float price;

	public String getAuthor() {
		return author;
	}

	public void setAuthor(String author) {
		this.author = author;
	}

	public String getISDN() {
		return ISDN;
	}

	public void setISDN(String isdn) {
		ISDN = isdn;
	}

	public float getPrice() {
		return price;
	}

	public void setPrice(int price) {
		this.price = price;
	}

	public String getTitle() {
		return title;
	}

	public void setTitle(String title) {
		this.title = title;
	}
}

1. You will need to represent the BookObject class as a business object. If you do not already have a business object to represent BookObject, the easiest way to accomplish this would be to create a business object with four fields to represent the four fields of the BookObject class. Right click Data in your module, and select New > Business Object from the contextual menu. Specify an appropriate name such as BookObjectBO for your business object, and select Finish. Add the appropriate fields to your business object to fully describe it, and save.
   
2. You will now need to create a JMS data binding that would map the BookObject class to the business object BookObjectBO created in step 1. The data binding implementation must implement com.ibm.websphere.sca.jms.data.JMSDataBinding. The skeleton of such a class is shown as follows:

   import javax.jms.JMSException;
   import javax.jms.Message;
   
   import com.ibm.websphere.sca.jms.data.JMSDataBinding;
   import commonj.connector.runtime.DataBindingException;
   import commonj.sdo.DataObject;
   
   public class BookObjectDataBinding implements JMSDataBinding {
   
   public int getMessageType() {return 0;}
   public void read(Message arg0) throws JMSException {}
   public void write(Message arg0) throws JMSException {}
   public boolean isBusinessException() {return false;}
   public void setBusinessException(boolean arg0) {}
   public DataObject getDataObject() throws DataBindingException {return null;}
   public void setDataObject(DataObject arg0) throws DataBindingException {}
   }

3. You will now need to provide the implementation. For a detailed description of the methods, see Overview of JMS, MQ JMS and generic JMS bindings. The following implementation of the getMessageType(), read(Message arg0) and write(Message arg0) could be used to map between the BookObjectBO business object and the BookObject class.

   	public void read(Message message) throws JMSException {
   		//		 Get the payload of the JMS Object message
   		BookObject bookObj = (BookObject) ((ObjectMessage) message).getObject();
   
   		//		 Create the SDO
   		com.ibm.websphere.sca.ServiceManager serviceManager = new com.ibm.websphere.sca.ServiceManager();
   		com.ibm.websphere.bo.BOFactory factory = (com.ibm.websphere.bo.BOFactory) serviceManager
   				.locateService("com/ibm/websphere/bo/BOFactory");
   		DataObject bookBO = factory.create("http://BB_Books_SCA",
   				"BookObjectBO");
   
   		bookBO.setString("ISDN", bookObj.getISDN());
   		bookBO.setString("Author", bookObj.getAuthor());
   		bookBO.setString("Title", bookObj.getTitle());
   		bookBO.setFloat("Price", bookObj.getPrice());
   
   		try {
   			//		 Set the data object
   			setDataObject(bookBO);
   		} catch (DataBindingException e) {
   			throw new JMSException(e.getLocalizedMessage());
   		}
   	}
   
   	public void write(Message message) throws JMSException {
   		try {
   			//		 Get the data object
   			DataObject bookBO = getDataObject();
   
   			//		 Create the Book Object
   			BookObject bookObj = new BookObject();
   			bookObj.setISDN(bookBO.getString("ISDN"));
   			bookObj.setAuthor(bookBO.getString("Author"));
   			bookObj.setTitle(bookBO.getString("Title"));
   			bookObj.setPrice(bookBO.getFloat("Price"));
   
   			//		 Set the payload of the JMS Object Message
   			((ObjectMessage) message).setObject(bookObj);
   
   		} catch (DataBindingException e) {
   			throw new JMSException(e.getLocalizedMessage());
   		}
   	}