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.ScheduledExecutorService; 020 import java.util.concurrent.ScheduledFuture; 021 import java.util.concurrent.TimeUnit; 022 023 import org.apache.camel.Endpoint; 024 import org.apache.camel.Exchange; 025 import org.apache.camel.Processor; 026 import org.apache.commons.logging.Log; 027 import org.apache.commons.logging.LogFactory; 028 029 /** 030 * A useful base class for any consumer which is polling based 031 * 032 * @version $Revision: 41580 $ 033 */ 034 public abstract class ScheduledPollConsumer<E extends Exchange> extends DefaultConsumer<E> implements 035 Runnable { 036 private static final transient Log LOG = LogFactory.getLog(ScheduledPollConsumer.class); 037 038 private final ScheduledExecutorService executor; 039 private long initialDelay = 1000; 040 private long delay = 500; 041 private TimeUnit timeUnit = TimeUnit.MILLISECONDS; 042 private boolean useFixedDelay; 043 private ScheduledFuture<?> future; 044 045 public ScheduledPollConsumer(DefaultEndpoint<E> endpoint, Processor processor) { 046 this(endpoint, processor, endpoint.getExecutorService()); 047 } 048 049 public ScheduledPollConsumer(Endpoint<E> endpoint, Processor processor, ScheduledExecutorService executor) { 050 super(endpoint, processor); 051 this.executor = executor; 052 if (executor == null) { 053 throw new IllegalArgumentException("A non null ScheduledExecutorService must be provided."); 054 } 055 } 056 057 /** 058 * Invoked whenever we should be polled 059 */ 060 public void run() { 061 if (LOG.isDebugEnabled()) { 062 LOG.debug("Starting to poll: " + this.getEndpoint()); 063 } 064 try { 065 poll(); 066 } catch (Exception e) { 067 // TODO: We should not swallow this but handle it better. See CAMEL-501 068 LOG.warn("An exception occured while polling: " + this.getEndpoint() + ": " + e.getMessage(), e); 069 } 070 } 071 072 // Properties 073 // ------------------------------------------------------------------------- 074 public long getInitialDelay() { 075 return initialDelay; 076 } 077 078 public void setInitialDelay(long initialDelay) { 079 this.initialDelay = initialDelay; 080 } 081 082 public long getDelay() { 083 return delay; 084 } 085 086 public void setDelay(long delay) { 087 this.delay = delay; 088 } 089 090 public TimeUnit getTimeUnit() { 091 return timeUnit; 092 } 093 094 public void setTimeUnit(TimeUnit timeUnit) { 095 this.timeUnit = timeUnit; 096 } 097 098 public boolean isUseFixedDelay() { 099 return useFixedDelay; 100 } 101 102 public void setUseFixedDelay(boolean useFixedDelay) { 103 this.useFixedDelay = useFixedDelay; 104 } 105 106 // Implementation methods 107 // ------------------------------------------------------------------------- 108 109 /** 110 * The polling method which is invoked periodically to poll this consumer 111 * 112 * @throws Exception can be thrown if an exception occured during polling 113 */ 114 protected abstract void poll() throws Exception; 115 116 @Override 117 protected void doStart() throws Exception { 118 super.doStart(); 119 if (isUseFixedDelay()) { 120 future = executor.scheduleWithFixedDelay(this, getInitialDelay(), getDelay(), getTimeUnit()); 121 } else { 122 future = executor.scheduleAtFixedRate(this, getInitialDelay(), getDelay(), getTimeUnit()); 123 } 124 } 125 126 @Override 127 protected void doStop() throws Exception { 128 if (future != null) { 129 future.cancel(false); 130 } 131 super.doStop(); 132 } 133 }