/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can obtain
* a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
* or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
* Sun designates this particular file as subject to the "Classpath" exception
* as provided by Sun in the GPL Version 2 section of the License file that
* accompanied this code. If applicable, add the following below the License
* Header, with the fields enclosed by brackets [] replaced by your own
* identifying information: "Portions Copyrighted [year]
* [name of copyright owner]"
*
* Contributor(s):
*
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
//NOTE: Tabs are used instead of spaces for indentation.
// Make sure that your editor does not replace tabs with spaces.
// Set the tab length using your favourite editor to your
// visual preference.
/*
* Filename: BlockingQueue.java
*
* Copyright 2000-2001 by iPlanet/Sun Microsystems, Inc.,
* 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
* All rights reserved.
*
* This software is the confidential and proprietary information
* of iPlanet/Sun Microsystems, Inc. ("Confidential Information").
* You shall not disclose such Confidential Information and shall
* use it only in accordance with the terms of the license
* agreement you entered into with iPlanet/Sun Microsystems.
*/
/**
* <BR> <I>$Source: /cvs/glassfish/appserv-commons/src/java/com/sun/enterprise/util/collection/BlockingQueue.java,v $</I>
* @author $Author: tcfujii $
* @version $Revision: 1.4 $ $Date: 2007/05/05 05:32:10 $
*/
package com.sun.enterprise.util.collection;
import java.util.LinkedList;
import java.util.Collection;
import com.sun.enterprise.util.pool.TimedoutException;
//Bug 4677074 begin
import java.util.logging.Logger;
import java.util.logging.Level;
import com.sun.logging.LogDomains;
//Bug 4677074 end
/**
* A BlockingQueue is a queue where remove() blocks if the queue is empty. The thread calling
* remove() blocks if the queue is empty while the add() notifies any waiting thread.
*/
/*
* NOTE:- Make sure that you synchronize the entire object on critical sections. For example,
* DO NOT try to synchronize just the access to the lnked list, because the FastThreadPool
*
*/
public class BlockingQueue {
//Bug 4677074 begin
static Logger _logger=LogDomains.getLogger(LogDomains.UTIL_LOGGER);
//Bug 4677074 end
private boolean closed = false;
private boolean aborted = false;
private int limit;
private LinkedList list;
private int waiters=0; // added for 4682740
/**
* Create a BlockingQueue that has an infinite queuelength with the
* specified timeout.
* @param The maximum time remove() will block.
* @see remove()
*/
public BlockingQueue() {
this(Integer.MAX_VALUE);
}
/**
* Create a BlockingQueue that has the specified queue limit with the
* specified timeout.
* @param The maximum time remove() will block.
* @param The queue length after which TooManyTasksException is thrown.
* @see remove()
*/
public BlockingQueue(int queueLimit) {
this.limit = queueLimit;
this.list = new LinkedList();
// START OF IASRI 4682740
com.sun.enterprise.util.MonitorTask.addORBMonitorable(this);
// END OF IASRI 4682740
}
/**
* Add to the head of the queue. Probably a high priority job?
*/
public void addFirst(Object object)
throws TooManyTasksException, QueueClosedException
{
if (closed)
throw new QueueClosedException("Queue closed.");
synchronized (list) {
if (list.size() >= limit) {
throw new TooManyTasksException("Too many tasks in queue...");
}
list.addFirst(object);
list.notify();
}
}
/**
* Add to the tail of the queue.
*/
public void addLast(Object object)
throws TooManyTasksException, QueueClosedException
{
if (closed)
throw new QueueClosedException("Queue closed.");
synchronized (list) {
if (list.size() >= limit) {
throw new TooManyTasksException("Too many tasks in queue...");
}
list.add(object);
list.notify();
}
}
/**
* Add the job at the specified position. Probably based on priority?
*/
public void add(int index, Object object)
throws TooManyTasksException, QueueClosedException
{
if (closed)
throw new QueueClosedException("Queue closed.");
synchronized (list) {
if (list.size() >= limit) {
throw new TooManyTasksException("Too many tasks in queue...");
}
list.add(index, object);
list.notify();
}
}
/**
* Appends all of the elements in the specified collection to the end of
* this list, in the order that they are returned by the specified
* collection's iterator.
*/
public void addAll(Collection c)
throws TooManyTasksException, QueueClosedException
{
if (closed)
throw new QueueClosedException("Queue closed.");
synchronized (list) {
if (list.size() >= limit) {
throw new TooManyTasksException("Too many tasks in queue...");
}
list.addAll(c);
list.notify();
}
}
/**
*
*/
public int size() {
synchronized (list) {
return list.size();
}
}
// Start 4682740 - ORB to support standalone monitoring
/**
* Return the size of the queue, unsynchronized method.
*/
public int getUnsyncSize () {
return list.size();
}
/**
* Return the number of waiting Threads on the queue.
*/
public int getUnsyncWaitingThreads () {
return waiters;
}
/**
* Return a String with information about this queue. Good for monitoring.
*/
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append("BlockingQueue [TW=").append(waiters);
sb.append(", CS=").append(list.size());
sb.append(", MS=").append(limit).append("]");
return sb.toString();
}
// End 4682740 - ORB to support standalone monitoring
/**
* Remove a task from the queue. If there are no objects then the thread blocks. The thread
* will be notified if any object is added to the queue.
* @return An object from the queue.
*/
public Object remove(boolean canWait)
throws InterruptedException, QueueClosedException
{
while (true) {
if (aborted) {
throw new QueueClosedException("Queue closed....");
}
synchronized (list) {
if (list.size() > 0) {
//System.out.println(Thread.currentThread().getName() + ": GOT SOME TASK!!....");
//Bug 4677074 begin
//_logger.log(Level.FINE,Thread.currentThread().getName() + ": GOT SOME TASK!!....");
//Bug 4677074 end
return list.removeFirst();
}
if (closed) {
throw new QueueClosedException("Queue closed....");
} else {
if (! canWait) {
return null;
}
//System.out.println(Thread.currentThread().getName() + ": waiting....");
//Bug 4677074 begin
//_logger.log(Level.FINE,Thread.currentThread().getName() + ": waiting....");
//Bug 4677074 end
waiters++; // added for 4682740
list.wait();
waiters--; // added for 4682740
}
}
}
}
/**
* Remove a task from the queue. If there are no objects then the thread blocks. The thread
* will be notified if any object is added to the queue.
* @return An object from the queue.
*/
public Object remove(long waitFor)
throws InterruptedException, QueueClosedException
{
// Fixed for Bug No. 4673949
if (aborted) {
throw new QueueClosedException("Queue closed....");
}
synchronized (list) {
if (list.size() > 0) {
//System.out.println(Thread.currentThread().getName() + ": GOT SOME TASK!!....");
//Bug 4677074 begin
//_logger.log(Level.FINE,Thread.currentThread().getName() + ": GOT SOME TASK!!....");
//Bug 4677074 end
return list.removeFirst();
}
if (closed) {
throw new QueueClosedException("Queue closed....");
} else {
waiters++; // added for 4682740
list.wait(waitFor);
waiters--; // added for 4682740
if (list.size() > 0) {
//System.out.println(Thread.currentThread().getName() + ": GOT SOME TASK!!....");
//Bug 4677074 begin
//_logger.log(Level.FINE,Thread.currentThread().getName() + ": GOT SOME TASK!!....");
//Bug 4677074 end
return list.removeFirst();
} else {
// We timed out
return null;
}
}
} //Synchronized list
}
public void shutdown() {
this.closed = true;
synchronized (list) {
list.notifyAll();
}
}
public void abort() {
this.closed = this.aborted = true;
synchronized (list) {
list.notifyAll();
}
}
}
|