jakarta.jms.QueueRequestor Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2017 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package jakarta.jms;
/**
* The {@code QueueRequestor} helper class simplifies making service requests.
*
*
* The {@code QueueRequestor} constructor is given a non-transacted {@code QueueSession} and a destination
* {@code Queue}. It creates a {@code TemporaryQueue} for the responses and provides a {@code request} method that sends
* the request message and waits for its reply.
*
*
* This is a very basic request/reply abstraction which assumes the session is non-transacted with a delivery mode of
* either AUTO_ACKNOWLEDGE or DUPS_OK_ACKNOWLEDGE. It is expected that most applications will create less basic
* implementations.
*
* @see jakarta.jms.TopicRequestor
*
* @version Jakarta Messaging 2.0
* @since JMS 1.0
*/
public class QueueRequestor {
QueueSession session; // The queue session the queue belongs to.
TemporaryQueue tempQueue;
QueueSender sender;
QueueReceiver receiver;
/**
* Constructor for the {@code QueueRequestor} class.
*
*
* This implementation assumes the session parameter to be non-transacted, with a delivery mode of either
* {@code AUTO_ACKNOWLEDGE} or {@code DUPS_OK_ACKNOWLEDGE}.
*
* @param session the {@code QueueSession} the queue belongs to
* @param queue the queue to perform the request/reply call on
*
* @exception JMSException if the Jakarta Messaging provider fails to create the {@code QueueRequestor} due to some internal error.
* @exception InvalidDestinationException if an invalid queue is specified.
*/
public QueueRequestor(QueueSession session, Queue queue) throws JMSException {
if (queue == null) {
throw new InvalidDestinationException("queue==null");
}
this.session = session;
tempQueue = session.createTemporaryQueue();
sender = session.createSender(queue);
receiver = session.createReceiver(tempQueue);
}
/**
* Sends a request and waits for a reply. The temporary queue is used for the {@code JMSReplyTo} destination, and only
* one reply per request is expected.
*
* @param message the message to send
*
* @return the reply message
*
* @exception JMSException if the Jakarta Messaging provider fails to complete the request due to some internal error.
*/
public Message request(Message message) throws JMSException {
message.setJMSReplyTo(tempQueue);
sender.send(message);
return (receiver.receive());
}
/**
* Closes the {@code QueueRequestor} and its session.
*
*
* Since a provider may allocate some resources on behalf of a {@code QueueRequestor} outside the Java virtual machine,
* clients should close them when they are not needed. Relying on garbage collection to eventually reclaim these
* resources may not be timely enough.
*
*
* Note that this method closes the {@code QueueSession} object passed to the {@code QueueRequestor} constructor.
*
* @exception JMSException if the Jakarta Messaging provider fails to close the {@code QueueRequestor} due to some internal error.
*/
public void close() throws JMSException {
// publisher and consumer created by constructor are implicitly closed.
session.close();
tempQueue.delete();
}
}