Java tutorial
/* * Copyright 2013 The Netty Project * * The Netty Project 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 io.netty.util.concurrent; import io.netty.util.internal.UnstableApi; import io.netty.util.internal.logging.InternalLogger; import io.netty.util.internal.logging.InternalLoggerFactory; import java.util.Collection; import java.util.Collections; import java.util.Iterator; import java.util.List; import java.util.concurrent.AbstractExecutorService; import java.util.concurrent.Callable; import java.util.concurrent.RunnableFuture; import java.util.concurrent.TimeUnit; /** * Abstract base class for {@link EventExecutor} implementations. */ public abstract class AbstractEventExecutor extends AbstractExecutorService implements EventExecutor { private static final InternalLogger logger = InternalLoggerFactory.getInstance(AbstractEventExecutor.class); static final long DEFAULT_SHUTDOWN_QUIET_PERIOD = 2; static final long DEFAULT_SHUTDOWN_TIMEOUT = 15; private final EventExecutorGroup parent; private final Collection<EventExecutor> selfCollection = Collections.<EventExecutor>singleton(this); protected AbstractEventExecutor() { this(null); } protected AbstractEventExecutor(EventExecutorGroup parent) { this.parent = parent; } @Override public EventExecutorGroup parent() { return parent; } @Override public EventExecutor next() { return this; } @Override public boolean inEventLoop() { return inEventLoop(Thread.currentThread()); } @Override public Iterator<EventExecutor> iterator() { return selfCollection.iterator(); } @Override public Future<?> shutdownGracefully() { return shutdownGracefully(DEFAULT_SHUTDOWN_QUIET_PERIOD, DEFAULT_SHUTDOWN_TIMEOUT, TimeUnit.SECONDS); } /** * @deprecated {@link #shutdownGracefully(long, long, TimeUnit)} or {@link #shutdownGracefully()} instead. */ @Override @Deprecated public abstract void shutdown(); /** * @deprecated {@link #shutdownGracefully(long, long, TimeUnit)} or {@link #shutdownGracefully()} instead. */ @Override @Deprecated public List<Runnable> shutdownNow() { shutdown(); return Collections.emptyList(); } @Override public <V> Promise<V> newPromise() { return new DefaultPromise<V>(this); } @Override public <V> ProgressivePromise<V> newProgressivePromise() { return new DefaultProgressivePromise<V>(this); } @Override public <V> Future<V> newSucceededFuture(V result) { return new SucceededFuture<V>(this, result); } @Override public <V> Future<V> newFailedFuture(Throwable cause) { return new FailedFuture<V>(this, cause); } @Override public Future<?> submit(Runnable task) { return (Future<?>) super.submit(task); } @Override public <T> Future<T> submit(Runnable task, T result) { return (Future<T>) super.submit(task, result); } @Override public <T> Future<T> submit(Callable<T> task) { return (Future<T>) super.submit(task); } @Override protected final <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) { return new PromiseTask<T>(this, runnable, value); } @Override protected final <T> RunnableFuture<T> newTaskFor(Callable<T> callable) { return new PromiseTask<T>(this, callable); } @Override public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) { throw new UnsupportedOperationException(); } @Override public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) { throw new UnsupportedOperationException(); } @Override public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) { throw new UnsupportedOperationException(); } @Override public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) { throw new UnsupportedOperationException(); } /** * Try to execute the given {@link Runnable} and just log if it throws a {@link Throwable}. */ protected static void safeExecute(Runnable task) { try { task.run(); } catch (Throwable t) { logger.warn("A task raised an exception. Task: {}", task, t); } } /** * Like {@link #execute(Runnable)} but does not guarantee the task will be run until either * a non-lazy task is executed or the executor is shut down. * * This is equivalent to submitting a {@link EventExecutor.LazyRunnable} to * {@link #execute(Runnable)} but for an arbitrary {@link Runnable}. * * The default implementation just delegates to {@link #execute(Runnable)}. */ @UnstableApi public void lazyExecute(Runnable task) { execute(task); } /** * Marker interface for {@link Runnable} to indicate that it should be queued for execution * but does not need to run immediately. */ @UnstableApi public interface LazyRunnable extends Runnable { } }