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