001/*
002 * Copyright 2002-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.core.task.support;
018
019import java.util.List;
020import java.util.concurrent.AbstractExecutorService;
021import java.util.concurrent.TimeUnit;
022
023import org.springframework.core.task.TaskExecutor;
024import org.springframework.util.Assert;
025
026/**
027 * Adapter that takes a Spring {@link org.springframework.core.task.TaskExecutor}
028 * and exposes a full {@code java.util.concurrent.ExecutorService} for it.
029 *
030 * <p>This is primarily for adapting to client components that communicate via the
031 * {@code java.util.concurrent.ExecutorService} API. It can also be used as
032 * common ground between a local Spring {@code TaskExecutor} backend and a
033 * JNDI-located {@code ManagedExecutorService} in a Java EE 7 environment.
034 *
035 * <p><b>NOTE:</b> This ExecutorService adapter does <em>not</em> support the
036 * lifecycle methods in the {@code java.util.concurrent.ExecutorService} API
037 * ("shutdown()" etc), similar to a server-wide {@code ManagedExecutorService}
038 * in a Java EE 7 environment. The lifecycle is always up to the backend pool,
039 * with this adapter acting as an access-only proxy for that target pool.
040 *
041 * @author Juergen Hoeller
042 * @since 3.0
043 * @see java.util.concurrent.ExecutorService
044 */
045public class ExecutorServiceAdapter extends AbstractExecutorService {
046
047        private final TaskExecutor taskExecutor;
048
049
050        /**
051         * Create a new ExecutorServiceAdapter, using the given target executor.
052         * @param taskExecutor the target executor to delegate to
053         */
054        public ExecutorServiceAdapter(TaskExecutor taskExecutor) {
055                Assert.notNull(taskExecutor, "TaskExecutor must not be null");
056                this.taskExecutor = taskExecutor;
057        }
058
059
060        @Override
061        public void execute(Runnable task) {
062                this.taskExecutor.execute(task);
063        }
064
065        @Override
066        public void shutdown() {
067                throw new IllegalStateException(
068                                "Manual shutdown not supported - ExecutorServiceAdapter is dependent on an external lifecycle");
069        }
070
071        @Override
072        public List<Runnable> shutdownNow() {
073                throw new IllegalStateException(
074                                "Manual shutdown not supported - ExecutorServiceAdapter is dependent on an external lifecycle");
075        }
076
077        @Override
078        public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
079                throw new IllegalStateException(
080                                "Manual shutdown not supported - ExecutorServiceAdapter is dependent on an external lifecycle");
081        }
082
083        @Override
084        public boolean isShutdown() {
085                return false;
086        }
087
088        @Override
089        public boolean isTerminated() {
090                return false;
091        }
092
093}