/*
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.core.task.support;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import java.util.concurrent.RejectedExecutionException;
import org.springframework.core.task.AsyncListenableTaskExecutor;
import org.springframework.core.task.TaskDecorator;
import org.springframework.core.task.TaskRejectedException;
import org.springframework.util.Assert;
import org.springframework.util.concurrent.ListenableFuture;
import org.springframework.util.concurrent.ListenableFutureTask;
/**
* Adapter that takes a JDK {@code java.util.concurrent.Executor} and
* exposes a Spring {@link org.springframework.core.task.TaskExecutor} for it.
* Also detects an extended {@code java.util.concurrent.ExecutorService}, adapting
* the {@link org.springframework.core.task.AsyncTaskExecutor} interface accordingly.
*
* @author Juergen Hoeller
* @since 3.0
* @see java.util.concurrent.Executor
* @see java.util.concurrent.ExecutorService
* @see java.util.concurrent.Executors
*/
public class TaskExecutorAdapter implements AsyncListenableTaskExecutor {
private final Executor concurrentExecutor;
private TaskDecorator taskDecorator;
/**
* Create a new TaskExecutorAdapter,
* using the given JDK concurrent executor.
* @param concurrentExecutor the JDK concurrent executor to delegate to
*/
public TaskExecutorAdapter(Executor concurrentExecutor) {
Assert.notNull(concurrentExecutor, "Executor must not be null");
this.concurrentExecutor = concurrentExecutor;
}
/**
* Specify a custom {@link TaskDecorator} to be applied to any {@link Runnable}
* about to be executed.
* <p>Note that such a decorator is not necessarily being applied to the
* user-supplied {@code Runnable}/{@code Callable} but rather to the actual
* execution callback (which may be a wrapper around the user-supplied task).
* <p>The primary use case is to set some execution context around the task's
* invocation, or to provide some monitoring/statistics for task execution.
* @since 4.3
*/
public final void setTaskDecorator(TaskDecorator taskDecorator) {
this.taskDecorator = taskDecorator;
}
/**
* Delegates to the specified JDK concurrent executor.
* @see java.util.concurrent.Executor#execute(Runnable)
*/
@Override
public void execute(Runnable task) {
try {
doExecute(this.concurrentExecutor, this.taskDecorator, task);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException(
"Executor [" + this.concurrentExecutor + "] did not accept task: " + task, ex);
}
}
@Override
public void execute(Runnable task, long startTimeout) {
execute(task);
}
@Override
public Future<?> submit(Runnable task) {
try {
if (this.taskDecorator == null && this.concurrentExecutor instanceof ExecutorService) {
return ((ExecutorService) this.concurrentExecutor).submit(task);
}
else {
FutureTask<Object> future = new FutureTask<>(task, null);
doExecute(this.concurrentExecutor, this.taskDecorator, future);
return future;
}
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException(
"Executor [" + this.concurrentExecutor + "] did not accept task: " + task, ex);
}
}
@Override
public <T> Future<T> submit(Callable<T> task) {
try {
if (this.taskDecorator == null && this.concurrentExecutor instanceof ExecutorService) {
return ((ExecutorService) this.concurrentExecutor).submit(task);
}
else {
FutureTask<T> future = new FutureTask<>(task);
doExecute(this.concurrentExecutor, this.taskDecorator, future);
return future;
}
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException(
"Executor [" + this.concurrentExecutor + "] did not accept task: " + task, ex);
}
}
@Override
public ListenableFuture<?> submitListenable(Runnable task) {
try {
ListenableFutureTask<Object> future = new ListenableFutureTask<>(task, null);
doExecute(this.concurrentExecutor, this.taskDecorator, future);
return future;
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException(
"Executor [" + this.concurrentExecutor + "] did not accept task: " + task, ex);
}
}
@Override
public <T> ListenableFuture<T> submitListenable(Callable<T> task) {
try {
ListenableFutureTask<T> future = new ListenableFutureTask<>(task);
doExecute(this.concurrentExecutor, this.taskDecorator, future);
return future;
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException(
"Executor [" + this.concurrentExecutor + "] did not accept task: " + task, ex);
}
}
/**
* Actually execute the given {@code Runnable} (which may be a user-supplied task
* or a wrapper around a user-supplied task) with the given executor.
* @param concurrentExecutor the underlying JDK concurrent executor to delegate to
* @param taskDecorator the specified decorator to be applied, if any
* @param runnable the runnable to execute
* @throws RejectedExecutionException if the given runnable cannot be accepted
* @since 4.3
*/
protected void doExecute(Executor concurrentExecutor, TaskDecorator taskDecorator, Runnable runnable)
throws RejectedExecutionException{
concurrentExecutor.execute(taskDecorator != null ? taskDecorator.decorate(runnable) : runnable);
}
}