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/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.activemq;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import org.apache.activemq.command.MessageDispatch;
public class SimplePriorityMessageDispatchChannel implements MessageDispatchChannel {
private static final Integer MAX_PRIORITY = 10;
private final Object mutex = new Object();
private final LinkedList[] lists;
private boolean closed;
private boolean running;
private int size = 0;
@SuppressWarnings("unchecked")
public SimplePriorityMessageDispatchChannel() {
this.lists = new LinkedList[MAX_PRIORITY];
for (int i = 0; i < MAX_PRIORITY; i++) {
lists[i] = new LinkedList();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#enqueue(org.apache.activemq.command.MessageDispatch)
*/
@Override
public void enqueue(MessageDispatch message) {
synchronized (mutex) {
getList(message).addLast(message);
this.size++;
mutex.notify();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#enqueueFirst(org.apache.activemq.command.MessageDispatch)
*/
@Override
public void enqueueFirst(MessageDispatch message) {
synchronized (mutex) {
getList(message).addFirst(message);
this.size++;
mutex.notify();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#isEmpty()
*/
@Override
public boolean isEmpty() {
return this.size == 0;
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#dequeue(long)
*/
@Override
public MessageDispatch dequeue(long timeout) throws InterruptedException {
synchronized (mutex) {
// Wait until the consumer is ready to deliver messages.
while (timeout != 0 && !closed && (isEmpty() || !running)) {
if (timeout == -1) {
mutex.wait();
} else {
mutex.wait(timeout);
break;
}
}
if (closed || !running || isEmpty()) {
return null;
}
return removeFirst();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#dequeueNoWait()
*/
@Override
public MessageDispatch dequeueNoWait() {
synchronized (mutex) {
if (closed || !running || isEmpty()) {
return null;
}
return removeFirst();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#peek()
*/
@Override
public MessageDispatch peek() {
synchronized (mutex) {
if (closed || !running || isEmpty()) {
return null;
}
return getFirst();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#start()
*/
@Override
public void start() {
synchronized (mutex) {
running = true;
mutex.notifyAll();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#stop()
*/
@Override
public void stop() {
synchronized (mutex) {
running = false;
mutex.notifyAll();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#close()
*/
@Override
public void close() {
synchronized (mutex) {
if (!closed) {
running = false;
closed = true;
}
mutex.notifyAll();
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#clear()
*/
@Override
public void clear() {
synchronized (mutex) {
for (int i = 0; i < MAX_PRIORITY; i++) {
lists[i].clear();
}
this.size = 0;
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#isClosed()
*/
@Override
public boolean isClosed() {
return closed;
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#size()
*/
@Override
public int size() {
synchronized (mutex) {
return this.size;
}
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#getMutex()
*/
@Override
public Object getMutex() {
return mutex;
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#isRunning()
*/
@Override
public boolean isRunning() {
return running;
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.MessageDispatchChannelI#removeAll()
*/
@Override
public List removeAll() {
synchronized (mutex) {
ArrayList result = new ArrayList(size());
for (int i = MAX_PRIORITY - 1; i >= 0; i--) {
List list = lists[i];
result.addAll(list);
size -= list.size();
list.clear();
}
return result;
}
}
@Override
public String toString() {
String result = "";
for (int i = MAX_PRIORITY - 1; i >= 0; i--) {
result += i + ":{" + lists[i].toString() + "}";
}
return result;
}
protected int getPriority(MessageDispatch message) {
int priority = javax.jms.Message.DEFAULT_PRIORITY;
if (message.getMessage() != null) {
priority = Math.max(message.getMessage().getPriority(), 0);
priority = Math.min(priority, 9);
}
return priority;
}
protected LinkedList getList(MessageDispatch md) {
return lists[getPriority(md)];
}
private final MessageDispatch removeFirst() {
if (this.size > 0) {
for (int i = MAX_PRIORITY - 1; i >= 0; i--) {
LinkedList list = lists[i];
if (!list.isEmpty()) {
this.size--;
return list.removeFirst();
}
}
}
return null;
}
private final MessageDispatch getFirst() {
if (this.size > 0) {
for (int i = MAX_PRIORITY - 1; i >= 0; i--) {
LinkedList list = lists[i];
if (!list.isEmpty()) {
return list.getFirst();
}
}
}
return null;
}
}