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.impl;
018
019import java.util.ArrayList;
020import java.util.Collection;
021import java.util.concurrent.ArrayBlockingQueue;
022import java.util.concurrent.BlockingQueue;
023import java.util.concurrent.ConcurrentHashMap;
024import java.util.concurrent.ConcurrentMap;
025
026import org.apache.camel.spi.ServicePool;
027import org.apache.camel.support.ServiceSupport;
028import org.apache.camel.util.ServiceHelper;
029import org.slf4j.Logger;
030import org.slf4j.LoggerFactory;
031
032/**
033 * Default implementation to inherit for a basic service pool.
034 *
035 * @version 
036 */
037public abstract class DefaultServicePool<Key, Service> extends ServiceSupport implements ServicePool<Key, Service> {
038    protected final Logger log = LoggerFactory.getLogger(getClass());
039    protected final ConcurrentMap<Key, BlockingQueue<Service>> pool = new ConcurrentHashMap<Key, BlockingQueue<Service>>();
040    protected int capacity = 100;
041
042    protected DefaultServicePool() {
043    }
044
045    public DefaultServicePool(int capacity) {
046        this.capacity = capacity;
047    }
048
049    public int getCapacity() {
050        return capacity;
051    }
052
053    public void setCapacity(int capacity) {
054        this.capacity = capacity;
055    }
056
057    public synchronized int size() {
058        int size = 0;
059        for (BlockingQueue<Service> entry : pool.values()) {
060            size += entry.size();
061        }
062        return size;
063    }
064
065    public synchronized Service addAndAcquire(Key key, Service service) {
066        BlockingQueue<Service> entry = pool.get(key);
067        if (entry == null) {
068            entry = new ArrayBlockingQueue<Service>(capacity);
069            pool.put(key, entry);
070        }
071        log.trace("AddAndAcquire key: {} service: {}", key, service);
072
073        // test if queue will be full
074        if (entry.size() >= capacity) {
075            throw new IllegalStateException("Queue full");
076        }
077        return service;
078    }
079
080    public synchronized Service acquire(Key key) {
081        BlockingQueue<Service> services = pool.get(key);
082        if (services == null || services.isEmpty()) {
083            log.trace("No free services in pool to acquire for key: {}", key);
084            return null;
085        }
086
087        Service answer = services.poll();
088        log.trace("Acquire: {} service: {}", key, answer);
089        return answer;
090    }
091
092    public synchronized void release(Key key, Service service) {
093        log.trace("Release: {} service: {}", key, service);
094        BlockingQueue<Service> services = pool.get(key);
095        if (services != null) {
096            services.add(service);
097        }
098    }
099
100    public void purge() {
101        pool.clear();
102    }
103
104    protected void doStart() throws Exception {
105        log.debug("Starting service pool: {}", this);
106    }
107
108    protected void doStop() throws Exception {
109        log.debug("Stopping service pool: {}", this);
110        for (BlockingQueue<Service> entry : pool.values()) {
111            Collection<Service> values = new ArrayList<Service>();
112            entry.drainTo(values);
113            ServiceHelper.stopServices(values);
114            entry.clear();
115        }
116        pool.clear();
117    }
118
119}