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.processor; 018 019 import org.apache.camel.Exchange; 020 import org.apache.camel.Expression; 021 import org.apache.camel.Processor; 022 023 /** 024 * A <a href="http://camel.apache.org/delayer.html">Delayer</a> which 025 * delays processing the exchange until the correct amount of time has elapsed 026 * using an expression to determine the delivery time. <p/> For example if you 027 * wish to delay JMS messages by 25 seconds from their publish time you could 028 * create an instance of this class with the expression 029 * <code>header("JMSTimestamp")</code> and a delay value of 25000L. 030 * 031 * @version $Revision: 747062 $ 032 */ 033 public class Delayer extends DelayProcessorSupport { 034 private Expression timeExpression; 035 private long delay; 036 037 public Delayer(Processor processor, Expression timeExpression, long delay) { 038 super(processor); 039 this.timeExpression = timeExpression; 040 this.delay = delay; 041 } 042 043 @Override 044 public String toString() { 045 return "Delayer[on: " + timeExpression + " delay: " + delay + " to: " + getProcessor() + "]"; 046 } 047 048 // Properties 049 // ------------------------------------------------------------------------- 050 public long getDelay() { 051 return delay; 052 } 053 054 /** 055 * Sets the delay from the publish time; which is typically the time from 056 * the expression or the current system time if none is available 057 */ 058 public void setDelay(long delay) { 059 this.delay = delay; 060 } 061 062 // Implementation methods 063 // ------------------------------------------------------------------------- 064 065 /** 066 * Waits for an optional time period before continuing to process the 067 * exchange 068 */ 069 protected void delay(Exchange exchange) throws Exception { 070 long time = 0; 071 if (timeExpression != null) { 072 Long longValue = timeExpression.evaluate(exchange, Long.class); 073 if (longValue != null) { 074 time = longValue; 075 } 076 } 077 if (time <= 0) { 078 time = defaultProcessTime(exchange); 079 } 080 081 time += delay; 082 083 waitUntil(time, exchange); 084 } 085 086 /** 087 * A Strategy Method to allow derived implementations to decide the current 088 * system time or some other default exchange property 089 */ 090 protected long defaultProcessTime(Exchange exchange) { 091 return currentSystemTime(); 092 } 093 094 }