ImmediateEventExecutor.java — netty Source File

Source Code

/*
 * 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:
 *
 *   https://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.ObjectUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.util.ArrayDeque;
import java.util.Queue;
import java.util.concurrent.TimeUnit;

/**
 * Executes {@link Runnable} objects in the caller's thread. If the {@link #execute(Runnable)} is reentrant it will be
 * queued until the original {@link Runnable} finishes execution.
 * <p>
 * All {@link Throwable} objects thrown from {@link #execute(Runnable)} will be swallowed and logged. This is to ensure
 * that all queued {@link Runnable} objects have the chance to be run.
 */
public final class ImmediateEventExecutor extends AbstractEventExecutor {
    private static final InternalLogger logger = InternalLoggerFactory.getInstance(ImmediateEventExecutor.class);
    public static final ImmediateEventExecutor INSTANCE = new ImmediateEventExecutor();
    /**
     * A Runnable will be queued if we are executing a Runnable. This is to prevent a {@link StackOverflowError}.
     */
    private static final FastThreadLocal<Queue<Runnable>> DELAYED_RUNNABLES = new FastThreadLocal<Queue<Runnable>>() {
        @Override
        protected Queue<Runnable> initialValue() throws Exception {
            return new ArrayDeque<Runnable>();
        }
    };
    /**
     * Set to {@code true} if we are executing a runnable.
     */
    private static final FastThreadLocal<Boolean> RUNNING = new FastThreadLocal<Boolean>() {
        @Override
        protected Boolean initialValue() throws Exception {
            return false;
        }
    };

    private final Future<?> terminationFuture = new FailedFuture<Object>(
            GlobalEventExecutor.INSTANCE, new UnsupportedOperationException());

    private ImmediateEventExecutor() { }

    @Override
// ... (102 more lines)