Java Enterprise in a Nutshell, Second Edition

Name

MessageConsumer

Synopsis

A message consumer is used by JMS clients to receive messages. A message consumer is created by a client by specifying a Destination from which to receive messages, and an optional message selector that filters messages according to their header fields and property values. The methods for creating MessageConsumers are defined in subclasses of the Connection interface.

A message selector is a filter string whose syntax is based on the SQL92 conditional expression syntax. More details on the syntax of message selectors can be found in chapter X, “Java Message Service”.

A client can use a MessageConsumer synchronously, by polling it using its receive methods, or asynchronously, by registering a MessageListener with the consumer. When a message arrives that matches the sending Destination and the message selector, then the onMessage() method on the registered listener is called.

MessageConsumers should be freed by calling their close() method, to free up any resources allocated for them by the provider.

public interface MessageConsumer {
// Public Instance Methods
   public abstract void close() throws JMSException;  
   public abstract MessageListener getMessageListener(
        ) throws JMSException;  
   public abstract String getMessageSelector(
        ) throws JMSException;  
   public abstract javax.jms.Message receive(
        ) throws JMSException;  
   public abstract javax.jms.Message receive(
        long timeout) throws JMSException;  
   public abstract javax.jms.Message receiveNoWait( ) throws JMSException; ...