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.Map;
020
021import org.apache.camel.CamelContext;
022import org.apache.camel.Endpoint;
023import org.apache.camel.Exchange;
024import org.apache.camel.FailedToCreateConsumerException;
025import org.apache.camel.IsSingleton;
026import org.apache.camel.PollingConsumer;
027import org.apache.camel.RuntimeCamelException;
028import org.apache.camel.ServicePoolAware;
029import org.apache.camel.spi.EndpointUtilizationStatistics;
030import org.apache.camel.spi.ServicePool;
031import org.apache.camel.support.ServiceSupport;
032import org.apache.camel.util.CamelContextHelper;
033import org.apache.camel.util.LRUCache;
034import org.apache.camel.util.LRUCacheFactory;
035import org.apache.camel.util.ServiceHelper;
036import org.slf4j.Logger;
037import org.slf4j.LoggerFactory;
038
039/**
040 * Cache containing created {@link org.apache.camel.Consumer}.
041 *
042 * @version 
043 */
044public class ConsumerCache extends ServiceSupport {
045    private static final Logger LOG = LoggerFactory.getLogger(ConsumerCache.class);
046
047    private final CamelContext camelContext;
048    private final ServicePool<Endpoint, PollingConsumer> pool;
049    private final Map<String, PollingConsumer> consumers;
050    private final Object source;
051
052    private EndpointUtilizationStatistics statistics;
053    private boolean extendedStatistics;
054    private int maxCacheSize;
055
056    public ConsumerCache(Object source, CamelContext camelContext) {
057        this(source, camelContext, CamelContextHelper.getMaximumCachePoolSize(camelContext));
058    }
059
060    public ConsumerCache(Object source, CamelContext camelContext, int cacheSize) {
061        this(source, camelContext, createLRUCache(cacheSize));
062    }
063    
064    public ConsumerCache(Object source, CamelContext camelContext, Map<String, PollingConsumer> cache) {
065        this(source, camelContext, cache, camelContext.getPollingConsumerServicePool());
066    }
067
068    public ConsumerCache(Object source, CamelContext camelContext, Map<String, PollingConsumer> cache, ServicePool<Endpoint, PollingConsumer> pool) {
069        this.camelContext = camelContext;
070        this.consumers = cache;
071        this.source = source;
072        this.pool = pool;
073        if (consumers instanceof LRUCache) {
074            maxCacheSize = ((LRUCache) consumers).getMaxCacheSize();
075        }
076
077        // only if JMX is enabled
078        if (camelContext.getManagementStrategy().getManagementAgent() != null) {
079            this.extendedStatistics = camelContext.getManagementStrategy().getManagementAgent().getStatisticsLevel().isExtended();
080        } else {
081            this.extendedStatistics = false;
082        }
083    }
084
085    public boolean isExtendedStatistics() {
086        return extendedStatistics;
087    }
088
089    /**
090     * Whether extended JMX statistics is enabled for {@link org.apache.camel.spi.EndpointUtilizationStatistics}
091     */
092    public void setExtendedStatistics(boolean extendedStatistics) {
093        this.extendedStatistics = extendedStatistics;
094    }
095
096    /**
097     * Creates the {@link LRUCache} to be used.
098     * <p/>
099     * This implementation returns a {@link LRUCache} instance.
100
101     * @param cacheSize the cache size
102     * @return the cache
103     */
104    @SuppressWarnings("unchecked")
105    protected static LRUCache<String, PollingConsumer> createLRUCache(int cacheSize) {
106        // Use a regular cache as we want to ensure that the lifecycle of the consumers
107        // being cache is properly handled, such as they are stopped when being evicted
108        // or when this cache is stopped. This is needed as some consumers requires to
109        // be stopped so they can shutdown internal resources that otherwise may cause leaks
110        return LRUCacheFactory.newLRUCache(cacheSize);
111    }
112    
113    /**
114     * Acquires a pooled PollingConsumer which you <b>must</b> release back again after usage using the
115     * {@link #releasePollingConsumer(org.apache.camel.Endpoint, org.apache.camel.PollingConsumer)} method.
116     *
117     * @param endpoint the endpoint
118     * @return the PollingConsumer
119     */
120    public PollingConsumer acquirePollingConsumer(Endpoint endpoint) {
121        return doGetPollingConsumer(endpoint, true);
122    }
123
124    /**
125     * Releases an acquired producer back after usage.
126     *
127     * @param endpoint the endpoint
128     * @param pollingConsumer the pollingConsumer to release
129     */
130    public void releasePollingConsumer(Endpoint endpoint, PollingConsumer pollingConsumer) {
131        if (pollingConsumer instanceof ServicePoolAware) {
132            // release back to the pool
133            pool.release(endpoint, pollingConsumer);
134        } else {
135            boolean singleton = false;
136            if (pollingConsumer instanceof IsSingleton) {
137                singleton = ((IsSingleton) pollingConsumer).isSingleton();
138            }
139            String key = endpoint.getEndpointUri();
140            boolean cached = consumers.containsKey(key);
141            if (!singleton || !cached) {
142                try {
143                    // stop and shutdown non-singleton/non-cached consumers as we should not leak resources
144                    if (!singleton) {
145                        LOG.debug("Released PollingConsumer: {} is stopped as consumer is not singleton", endpoint);
146                    } else {
147                        LOG.debug("Released PollingConsumer: {} is stopped as consumer cache is full", endpoint);
148                    }
149                    ServiceHelper.stopAndShutdownService(pollingConsumer);
150                } catch (Throwable ex) {
151                    if (ex instanceof RuntimeCamelException) {
152                        throw (RuntimeCamelException)ex;
153                    } else {
154                        throw new RuntimeCamelException(ex);
155                    }
156                }
157            }
158        }
159    }
160
161    public PollingConsumer getConsumer(Endpoint endpoint) {
162        return doGetPollingConsumer(endpoint, true);
163    }
164    
165    protected synchronized PollingConsumer doGetPollingConsumer(Endpoint endpoint, boolean pooled) {
166        String key = endpoint.getEndpointUri();
167        PollingConsumer answer = consumers.get(key);
168        if (pooled && answer == null) {
169            pool.acquire(endpoint);
170        }  
171        
172        if (answer == null) {
173            try {
174                answer = endpoint.createPollingConsumer();
175                answer.start();
176            } catch (Throwable e) {
177                throw new FailedToCreateConsumerException(endpoint, e);
178            }
179            if (pooled && answer instanceof ServicePoolAware) {
180                LOG.debug("Adding to producer service pool with key: {} for producer: {}", endpoint, answer);
181                answer = pool.addAndAcquire(endpoint, answer);
182            } else {
183                boolean singleton = false;
184                if (answer instanceof IsSingleton) {
185                    singleton = ((IsSingleton) answer).isSingleton();
186                }
187                if (singleton) {
188                    LOG.debug("Adding to consumer cache with key: {} for consumer: {}", endpoint, answer);
189                    consumers.put(key, answer);
190                } else {
191                    LOG.debug("Consumer for endpoint: {} is not singleton and thus not added to consumer cache", key);
192                }
193            }
194        }
195
196        if (answer != null) {
197            // record statistics
198            if (extendedStatistics) {
199                statistics.onHit(key);
200            }
201        }
202
203        return answer;
204    }
205 
206    public Exchange receive(Endpoint endpoint) {
207        LOG.debug("<<<< {}", endpoint);
208        PollingConsumer consumer = null;
209        try {
210            consumer = acquirePollingConsumer(endpoint);
211            return consumer.receive();
212        } finally {
213            if (consumer != null) {
214                releasePollingConsumer(endpoint, consumer);
215            }
216        }
217    }
218
219    public Exchange receive(Endpoint endpoint, long timeout) {
220        LOG.debug("<<<< {}", endpoint);
221        PollingConsumer consumer = null;
222        try {
223            consumer = acquirePollingConsumer(endpoint);
224            return consumer.receive(timeout);
225        } finally {
226            if (consumer != null) {
227                releasePollingConsumer(endpoint, consumer);
228            }
229        }
230    }
231
232    public Exchange receiveNoWait(Endpoint endpoint) {
233        LOG.debug("<<<< {}", endpoint);
234        PollingConsumer consumer = null;
235        try {
236            consumer = doGetPollingConsumer(endpoint, true);
237            return consumer.receiveNoWait();
238        } finally {
239            if (consumer != null) {
240                releasePollingConsumer(endpoint, consumer);
241            }
242        }
243    }
244    
245    public CamelContext getCamelContext() {
246        return camelContext;
247    }
248
249    /**
250     * Gets the source which uses this cache
251     *
252     * @return the source
253     */
254    public Object getSource() {
255        return source;
256    }
257
258    /**
259     * Returns the current size of the cache
260     *
261     * @return the current size
262     */
263    public int size() {
264        int size = consumers.size();
265        LOG.trace("size = {}", size);
266        return size;
267    }
268
269    /**
270     * Gets the maximum cache size (capacity).
271     * <p/>
272     * Will return <tt>-1</tt> if it cannot determine this if a custom cache was used.
273     *
274     * @return the capacity
275     */
276    public int getCapacity() {
277        int capacity = -1;
278        if (consumers instanceof LRUCache) {
279            LRUCache<String, PollingConsumer> cache = (LRUCache<String, PollingConsumer>)consumers;
280            capacity = cache.getMaxCacheSize();
281        }
282        return capacity;
283    }
284
285    /**
286     * Gets the cache hits statistic
287     * <p/>
288     * Will return <tt>-1</tt> if it cannot determine this if a custom cache was used.
289     *
290     * @return the hits
291     */
292    public long getHits() {
293        long hits = -1;
294        if (consumers instanceof LRUCache) {
295            LRUCache<String, PollingConsumer> cache = (LRUCache<String, PollingConsumer>)consumers;
296            hits = cache.getHits();
297        }
298        return hits;
299    }
300
301    /**
302     * Gets the cache misses statistic
303     * <p/>
304     * Will return <tt>-1</tt> if it cannot determine this if a custom cache was used.
305     *
306     * @return the misses
307     */
308    public long getMisses() {
309        long misses = -1;
310        if (consumers instanceof LRUCache) {
311            LRUCache<String, PollingConsumer> cache = (LRUCache<String, PollingConsumer>)consumers;
312            misses = cache.getMisses();
313        }
314        return misses;
315    }
316
317    /**
318     * Gets the cache evicted statistic
319     * <p/>
320     * Will return <tt>-1</tt> if it cannot determine this if a custom cache was used.
321     *
322     * @return the evicted
323     */
324    public long getEvicted() {
325        long evicted = -1;
326        if (consumers instanceof LRUCache) {
327            LRUCache<String, PollingConsumer> cache = (LRUCache<String, PollingConsumer>)consumers;
328            evicted = cache.getEvicted();
329        }
330        return evicted;
331    }
332
333    /**
334     * Resets the cache statistics
335     */
336    public void resetCacheStatistics() {
337        if (consumers instanceof LRUCache) {
338            LRUCache<String, PollingConsumer> cache = (LRUCache<String, PollingConsumer>)consumers;
339            cache.resetStatistics();
340        }
341        if (statistics != null) {
342            statistics.clear();
343        }
344    }
345
346    /**
347     * Purges this cache
348     */
349    public synchronized void purge() {
350        consumers.clear();
351        if (statistics != null) {
352            statistics.clear();
353        }
354    }
355
356    /**
357     * Cleanup the cache (purging stale entries)
358     */
359    public void cleanUp() {
360        if (consumers instanceof LRUCache) {
361            LRUCache<String, PollingConsumer> cache = (LRUCache<String, PollingConsumer>)consumers;
362            cache.cleanUp();
363        }
364    }
365
366    public EndpointUtilizationStatistics getEndpointUtilizationStatistics() {
367        return statistics;
368    }
369
370    @Override
371    public String toString() {
372        return "ConsumerCache for source: " + source + ", capacity: " + getCapacity();
373    }
374
375    protected void doStart() throws Exception {
376        if (extendedStatistics) {
377            int max = maxCacheSize == 0 ? CamelContextHelper.getMaximumCachePoolSize(camelContext) : maxCacheSize;
378            statistics = new DefaultEndpointUtilizationStatistics(max);
379        }
380
381        ServiceHelper.startServices(consumers.values());
382    }
383
384    protected void doStop() throws Exception {
385        // when stopping we intend to shutdown
386        ServiceHelper.stopAndShutdownServices(statistics, pool);
387        try {
388            ServiceHelper.stopAndShutdownServices(consumers.values());
389        } finally {
390            // ensure consumers are removed, and also from JMX
391            for (PollingConsumer consumer : consumers.values()) {
392                getCamelContext().removeService(consumer);
393            }
394        }
395        consumers.clear();
396        if (statistics != null) {
397            statistics.clear();
398        }
399    }
400
401}