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.util.concurrent; 018 019import java.util.concurrent.BlockingQueue; 020import java.util.concurrent.Callable; 021import java.util.concurrent.RejectedExecutionHandler; 022import java.util.concurrent.RunnableFuture; 023import java.util.concurrent.ThreadFactory; 024import java.util.concurrent.ThreadPoolExecutor; 025import java.util.concurrent.TimeUnit; 026 027/** 028 * Thread pool executor that creates {@link RejectableFutureTask} instead of 029 * {@link java.util.concurrent.FutureTask} when registering new tasks for execution. 030 * <p/> 031 * Instances of {@link RejectableFutureTask} are required to handle {@link org.apache.camel.ThreadPoolRejectedPolicy#Discard} 032 * and {@link org.apache.camel.ThreadPoolRejectedPolicy#DiscardOldest} policies correctly, e.g. notify 033 * {@link Callable} and {@link Runnable} tasks when they are rejected. 034 * To be notified of rejection tasks have to implement {@link org.apache.camel.Rejectable} interface: <br/> 035 * <code><pre> 036 * public class RejectableTask implements Runnable, Rejectable { 037 * @Override 038 * public void run() { 039 * // execute task 040 * } 041 * @Override 042 * public void reject() { 043 * // do something useful on rejection 044 * } 045 * } 046 * </pre></code> 047 * <p/> 048 * If the task does not implement {@link org.apache.camel.Rejectable} interface the behavior is exactly the same as with 049 * ordinary {@link ThreadPoolExecutor}. 050 * 051 * @see RejectableFutureTask 052 * @see org.apache.camel.Rejectable 053 * @see RejectableScheduledThreadPoolExecutor 054 */ 055public class RejectableThreadPoolExecutor extends ThreadPoolExecutor { 056 057 public RejectableThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, 058 BlockingQueue<Runnable> workQueue) { 059 super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue); 060 } 061 062 public RejectableThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, 063 BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory) { 064 super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory); 065 } 066 067 public RejectableThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, 068 BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler) { 069 super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, handler); 070 } 071 072 public RejectableThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, 073 BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler) { 074 super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, handler); 075 } 076 077 @Override 078 protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) { 079 return new RejectableFutureTask<T>(runnable, value); 080 } 081 082 @Override 083 protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) { 084 return new RejectableFutureTask<T>(callable); 085 } 086 087 @Override 088 public String toString() { 089 // the thread factory often have more precise details what the thread pool is used for 090 if (getThreadFactory() instanceof CamelThreadFactory) { 091 String name = ((CamelThreadFactory) getThreadFactory()).getName(); 092 return super.toString() + "[" + name + "]"; 093 } else { 094 return super.toString(); 095 } 096 } 097 098}