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org/springframework/core/task/support/TaskExecutorAdapter.java
/*
 * Copyright 2002-2009 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.AsyncTaskExecutor;
import org.springframework.core.task.TaskRejectedException;
import org.springframework.util.Assert;

/**
 * Adapter that takes a JDK 1.5 <code>java.util.concurrent.Executor</code> and
 * exposes a Spring {@link org.springframework.core.task.TaskExecutor} for it.
 * Also detects an extended <code>java.util.concurrent.ExecutorService</code>, 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 AsyncTaskExecutor {

  private Executor concurrentExecutor;


  /**
   * Create a new TaskExecutorAdapter,
   * using the given JDK 1.5 concurrent executor.
   @param concurrentExecutor the JDK 1.5 concurrent executor to delegate to
   */
  public TaskExecutorAdapter(Executor concurrentExecutor) {
    Assert.notNull(concurrentExecutor, "Executor must not be null");
    this.concurrentExecutor = concurrentExecutor;
  }


  /**
   * Delegates to the specified JDK 1.5 concurrent executor.
   @see java.util.concurrent.Executor#execute(Runnable)
   */
  public void execute(Runnable task) {
    try {
      this.concurrentExecutor.execute(task);
    }
    catch (RejectedExecutionException ex) {
      throw new TaskRejectedException(
          "Executor [" this.concurrentExecutor + "] did not accept task: " + task, ex);
    }
  }

  public void execute(Runnable task, long startTimeout) {
    execute(task);
  }

  public Future<?> submit(Runnable task) {
    try {
      if (this.concurrentExecutor instanceof ExecutorService) {
        return ((ExecutorServicethis.concurrentExecutor).submit(task);
      }
      else {
        FutureTask<Object> future = new FutureTask<Object>(task, null);
        this.concurrentExecutor.execute(future);
        return future;
      }
    }
    catch (RejectedExecutionException ex) {
      throw new TaskRejectedException(
          "Executor [" this.concurrentExecutor + "] did not accept task: " + task, ex);
    }
  }

  public <T> Future<T> submit(Callable<T> task) {
    try {
      if (this.concurrentExecutor instanceof ExecutorService) {
        return ((ExecutorServicethis.concurrentExecutor).submit(task);
      }
      else {
        FutureTask<T> future = new FutureTask<T>(task);
        this.concurrentExecutor.execute(future);
        return future;
      }
    }
    catch (RejectedExecutionException ex) {
      throw new TaskRejectedException(
          "Executor [" this.concurrentExecutor + "] did not accept task: " + task, ex);
    }
  }

}