com.sun.messaging.jmq.jmsclient.QueueBrowserImpl Maven / Gradle / Ivy
/*
* Copyright (c) 2000, 2020 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 com.sun.messaging.jmq.jmsclient;
import java.util.Enumeration;
import java.util.Vector;
import jakarta.jms.*;
import com.sun.messaging.AdministeredObject;
/**
* A client uses a QueueBrowser to look at messages on a queue without removing them.
*
*
* The browse methods return a java.util.Enumeration that is used to scan the queue's messages. It may be an enumeration
* of the entire content of a queue or it may only contain the messages matching a message selector.
*
*
* Messages may be arriving and expiring while the scan is done. JMS does not require the content of an enumeration to
* be a static snapshot of queue content. Whether these changes are visible or not depends on the JMS provider.
*
* @see jakarta.jms.QueueSession#createBrowser(Queue)
* @see jakarta.jms.QueueSession#createBrowser(Queue, String)
* @see jakarta.jms.QueueReceiver
*/
public class QueueBrowserImpl implements QueueBrowser {
private SessionImpl session = null;
private Queue queue = null;
private String messageSelector = null;
private Vector consumers = new Vector();
private boolean isClosed = false;
public QueueBrowserImpl(SessionImpl session, Queue queue) throws JMSException {
this(session, queue, null);
}
public QueueBrowserImpl(SessionImpl session, Queue queue, String selector) throws JMSException {
if (queue == null) {
String errorString = AdministeredObject.cr.getKString(AdministeredObject.cr.X_INVALID_DESTINATION_NAME, "null");
throw new InvalidDestinationException(errorString, AdministeredObject.cr.X_INVALID_DESTINATION_NAME);
}
this.session = session;
this.queue = queue;
this.messageSelector = selector;
init();
}
private void init() throws JMSException {
// ConnectionConsumer workaround 4715054
session.checkBrowserCreation();
session.verifyDestination(queue, messageSelector, true);
}
/**
* Get the queue associated with this queue browser.
*
* @return the queue
*
* @exception JMSException if JMS fails to get the queue associated with this Browser due to some JMS error.
*/
@Override
public Queue getQueue() throws JMSException {
checkState();
return queue;
}
/**
* Get this queue browser's message selector expression.
*
* @return this queue browser's message selector
*
* @exception JMSException if JMS fails to get the message selector for this browser due to some JMS error.
*/
@Override
public String getMessageSelector() throws JMSException {
checkState();
return messageSelector;
}
/**
* Get an enumeration for browsing the current queue messages in the order they would be received.
*
* @return an enumeration for browsing the messages
*
* @exception JMSException if JMS fails to get the enumeration for this browser due to some JMS error.
*/
@Override
public Enumeration getEnumeration() throws JMSException {
checkState();
return (new BrowserConsumer(this, queue, messageSelector));
}
protected void addBrowserConsumer(BrowserConsumer consumer) {
consumers.addElement(consumer);
}
protected void removeBrowserConsumer(BrowserConsumer consumer) {
consumers.removeElement(consumer);
}
/**
* Since a provider may allocate some resources on behalf of a QueueBrowser outside the JVM, clients should close them
* when they are not needed. Relying on garbage collection to eventually reclaim these resources may not be timely
* enough.
*
* @exception JMSException if a JMS fails to close this Browser due to some JMS error.
*/
@Override
public void close() throws JMSException {
BrowserConsumer consumer = null;
for (int i = consumers.size() - 1; i >= 0; i--) {
consumer = (BrowserConsumer) consumers.elementAt(i);
consumer.close();
}
isClosed = true;
}
protected SessionImpl getSession() {
return session;
}
protected void checkState() throws JMSException {
if (isClosed) {
String errorString = AdministeredObject.cr.getKString(AdministeredObject.cr.X_BROWSER_CLOSED);
throw new jakarta.jms.IllegalStateException(errorString, AdministeredObject.cr.X_BROWSER_CLOSED);
}
session.checkSessionState();
}
}