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 */ 017 package org.apache.camel.impl; 018 019 import java.util.concurrent.ExecutorService; 020 import java.util.concurrent.ScheduledExecutorService; 021 import java.util.concurrent.ScheduledFuture; 022 import java.util.concurrent.TimeUnit; 023 024 import org.apache.camel.Endpoint; 025 import org.apache.camel.PollingConsumerPollStrategy; 026 import org.apache.camel.Processor; 027 import org.apache.camel.util.ObjectHelper; 028 import org.apache.camel.util.concurrent.ExecutorServiceHelper; 029 import org.apache.commons.logging.Log; 030 import org.apache.commons.logging.LogFactory; 031 032 /** 033 * A useful base class for any consumer which is polling based 034 * 035 * @version $Revision: 789216 $ 036 */ 037 public abstract class ScheduledPollConsumer extends DefaultConsumer implements Runnable { 038 private static final transient Log LOG = LogFactory.getLog(ScheduledPollConsumer.class); 039 040 private final ScheduledExecutorService executor; 041 private ScheduledFuture<?> future; 042 043 // if adding more options then align with ScheduledPollEndpoint#configureScheduledPollConsumerProperties 044 private long initialDelay = 1000; 045 private long delay = 500; 046 private TimeUnit timeUnit = TimeUnit.MILLISECONDS; 047 private boolean useFixedDelay; 048 private PollingConsumerPollStrategy pollStrategy = new DefaultPollingConsumerPollStrategy(); 049 050 public ScheduledPollConsumer(DefaultEndpoint endpoint, Processor processor) { 051 super(endpoint, processor); 052 053 ScheduledExecutorService scheduled; 054 ExecutorService service = endpoint.getExecutorService(); 055 if (service instanceof ScheduledExecutorService) { 056 scheduled = (ScheduledExecutorService) service; 057 } else { 058 scheduled = ExecutorServiceHelper.newScheduledThreadPool(5, getEndpoint().getEndpointUri(), true); 059 } 060 061 this.executor = scheduled; 062 ObjectHelper.notNull(executor, "executor"); 063 } 064 065 public ScheduledPollConsumer(Endpoint endpoint, Processor processor, ScheduledExecutorService executor) { 066 super(endpoint, processor); 067 this.executor = executor; 068 ObjectHelper.notNull(executor, "executor"); 069 } 070 071 /** 072 * Invoked whenever we should be polled 073 */ 074 public void run() { 075 int retryCounter = -1; 076 boolean done = false; 077 078 while (!done) { 079 try { 080 // eager assume we are done 081 done = true; 082 if (isRunAllowed()) { 083 084 if (retryCounter == -1) { 085 if (LOG.isTraceEnabled()) { 086 LOG.trace("Starting to poll: " + this.getEndpoint()); 087 } 088 } else { 089 if (LOG.isDebugEnabled()) { 090 if (LOG.isDebugEnabled()) { 091 LOG.debug("Retrying attempt " + retryCounter + " to poll: " + this.getEndpoint()); 092 } 093 } 094 } 095 096 pollStrategy.begin(this, getEndpoint()); 097 retryCounter++; 098 poll(); 099 pollStrategy.commit(this, getEndpoint()); 100 } 101 } catch (Exception e) { 102 try { 103 boolean retry = pollStrategy.rollback(this, getEndpoint(), retryCounter, e); 104 if (retry) { 105 done = false; 106 } 107 } catch (Exception re) { 108 throw ObjectHelper.wrapRuntimeCamelException(re); 109 } 110 } 111 } 112 113 if (LOG.isTraceEnabled()) { 114 LOG.trace("Finished polling: " + this.getEndpoint()); 115 } 116 } 117 118 // Properties 119 // ------------------------------------------------------------------------- 120 public long getInitialDelay() { 121 return initialDelay; 122 } 123 124 public void setInitialDelay(long initialDelay) { 125 this.initialDelay = initialDelay; 126 } 127 128 public long getDelay() { 129 return delay; 130 } 131 132 public void setDelay(long delay) { 133 this.delay = delay; 134 } 135 136 public TimeUnit getTimeUnit() { 137 return timeUnit; 138 } 139 140 public void setTimeUnit(TimeUnit timeUnit) { 141 this.timeUnit = timeUnit; 142 } 143 144 public boolean isUseFixedDelay() { 145 return useFixedDelay; 146 } 147 148 public void setUseFixedDelay(boolean useFixedDelay) { 149 this.useFixedDelay = useFixedDelay; 150 } 151 152 public PollingConsumerPollStrategy getPollStrategy() { 153 return pollStrategy; 154 } 155 156 public void setPollStrategy(PollingConsumerPollStrategy pollStrategy) { 157 this.pollStrategy = pollStrategy; 158 } 159 160 // Implementation methods 161 // ------------------------------------------------------------------------- 162 163 /** 164 * The polling method which is invoked periodically to poll this consumer 165 * 166 * @throws Exception can be thrown if an exception occurred during polling 167 */ 168 protected abstract void poll() throws Exception; 169 170 @Override 171 protected void doStart() throws Exception { 172 super.doStart(); 173 if (isUseFixedDelay()) { 174 future = executor.scheduleWithFixedDelay(this, getInitialDelay(), getDelay(), getTimeUnit()); 175 } else { 176 future = executor.scheduleAtFixedRate(this, getInitialDelay(), getDelay(), getTimeUnit()); 177 } 178 } 179 180 @Override 181 protected void doStop() throws Exception { 182 if (future != null) { 183 future.cancel(false); 184 } 185 super.doStop(); 186 } 187 }