| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more contributor license |
| * agreements. See the NOTICE file distributed with this work for additional information regarding |
| * copyright ownership. The ASF licenses this file to You 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.apache.geode.internal.util; |
| |
| import java.util.Queue; |
| import java.util.concurrent.ConcurrentLinkedQueue; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.RejectedExecutionException; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| /** |
| * Wraps an executor with a task queue so that currently executing tasks can be aborted. |
| */ |
| public class AbortableTaskService { |
| /** the executor */ |
| private final Executor exec; |
| |
| /** the queue of executing tasks */ |
| private final Queue<AbortingRunnable> tasks; |
| |
| /** |
| * Provides an executable interface that can be aborted during execution. |
| */ |
| public interface AbortableTask { |
| /** |
| * Invoked to execute the task. The task implementation should periodically check the aborted |
| * flag and take appropriate action. |
| * |
| * @param aborted set to true when the task has been aborted |
| */ |
| void runOrAbort(AtomicBoolean aborted); |
| |
| /** |
| * Invoked when a task is aborted prior to execution. |
| */ |
| void abortBeforeRun(); |
| } |
| |
| public AbortableTaskService(Executor exec) { |
| this.exec = exec; |
| tasks = new ConcurrentLinkedQueue<AbortingRunnable>(); |
| } |
| |
| /** |
| * Executes the task using the embedded executor. |
| * |
| * @param task the task to execute |
| */ |
| public void execute(AbortableTask task) { |
| AbortingRunnable ar = new AbortingRunnable(task); |
| tasks.add(ar); |
| |
| try { |
| exec.execute(ar); |
| |
| } catch (RejectedExecutionException e) { |
| tasks.remove(ar); |
| throw e; |
| } |
| } |
| |
| /** |
| * Aborts all executing tasks. |
| */ |
| public void abortAll() { |
| for (AbortingRunnable ar : tasks) { |
| ar.abort(); |
| } |
| } |
| |
| /** |
| * Waits for all currently executing tasks to complete. |
| */ |
| public void waitForCompletion() { |
| boolean interrupted = false; |
| for (AbortingRunnable ar : tasks) { |
| try { |
| ar.waitForCompletion(); |
| } catch (InterruptedException e) { |
| interrupted = true; |
| } |
| } |
| |
| if (interrupted) { |
| Thread.currentThread().interrupt(); |
| } |
| } |
| |
| /** |
| * Returns true if all tasks are done or aborted. |
| */ |
| public boolean isCompleted() { |
| for (AbortingRunnable ar : tasks) { |
| synchronized (ar) { |
| if (!ar.done) { |
| return false; |
| } |
| } |
| } |
| return true; |
| } |
| |
| private class AbortingRunnable implements Runnable { |
| /** the task to execute */ |
| private final AbortableTask task; |
| |
| /** true if the task is aborted */ |
| private AtomicBoolean aborted; |
| |
| /** true if the task has begun */ |
| private AtomicBoolean hasStarted; |
| |
| /** true if the task is complete */ |
| private boolean done; |
| |
| public AbortingRunnable(AbortableTask task) { |
| this.task = task; |
| |
| aborted = new AtomicBoolean(false); |
| hasStarted = new AtomicBoolean(false); |
| |
| done = false; |
| } |
| |
| private synchronized void waitForCompletion() throws InterruptedException { |
| while (!done) { |
| wait(); |
| } |
| } |
| |
| private synchronized void signalDone() { |
| done = true; |
| notifyAll(); |
| } |
| |
| private void abort() { |
| aborted.set(true); |
| if (hasStarted.compareAndSet(false, true)) { |
| try { |
| task.abortBeforeRun(); |
| } finally { |
| tasks.remove(this); |
| signalDone(); |
| } |
| } |
| } |
| |
| @Override |
| public void run() { |
| if (hasStarted.compareAndSet(false, true)) { |
| try { |
| task.runOrAbort(aborted); |
| } finally { |
| tasks.remove(this); |
| signalDone(); |
| } |
| } |
| } |
| } |
| } |