001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.component.seda;
018
019import java.util.LinkedList;
020import java.util.List;
021import java.util.concurrent.BlockingQueue;
022
023import org.apache.camel.Exchange;
024
025/**
026 * Holder for queue references.
027 * <p/>
028 * This is used to keep track of the usages of the queues, so we know when a queue is no longer
029 * in use, and can safely be discarded.
030 */
031public final class QueueReference {
032
033    private final BlockingQueue<Exchange> queue;
034    private Integer size;
035    private Boolean multipleConsumers;
036
037    private List<SedaEndpoint> endpoints = new LinkedList<SedaEndpoint>();
038
039    QueueReference(BlockingQueue<Exchange> queue, Integer size, Boolean multipleConsumers) {
040        this.queue = queue;
041        this.size = size;
042        this.multipleConsumers = multipleConsumers;
043    }
044
045    synchronized void addReference(SedaEndpoint endpoint) {
046        if (!endpoints.contains(endpoint)) {
047            endpoints.add(endpoint);
048            // update the multipleConsumers setting if need
049            if (endpoint.isMultipleConsumers()) {
050                multipleConsumers = true;
051            }
052        }
053    }
054
055    synchronized void removeReference(SedaEndpoint endpoint) {
056        if (endpoints.contains(endpoint)) {
057            endpoints.remove(endpoint);
058        }
059    }
060
061    /**
062     * Gets the reference counter
063     */
064    public synchronized int getCount() {
065        return endpoints.size();
066    }
067
068    /**
069     * Gets the queue size
070     *
071     * @return <tt>null</tt> if unbounded
072     */
073    public Integer getSize() {
074        return size;
075    }
076
077    public Boolean getMultipleConsumers() {
078        return multipleConsumers;
079    }
080
081    /**
082     * Gets the queue
083     */
084    public BlockingQueue<Exchange> getQueue() {
085        return queue;
086    }
087
088    public synchronized boolean hasConsumers() {
089        for (SedaEndpoint endpoint : endpoints) {
090            if (endpoint.getConsumers().size() > 0) {
091                return true;
092            }
093        }
094
095        return false;
096    }
097}