ThreadDeathWatcher.java — netty Source File

Source Code

/*
 * Copyright 2014 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;

import io.netty.util.concurrent.DefaultThreadFactory;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.StringUtil;
import io.netty.util.internal.SystemPropertyUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * Checks if a thread is alive periodically and runs a task when a thread dies.
 * <p>
 * This thread starts a daemon thread to check the state of the threads being watched and to invoke their
 * associated {@link Runnable}s.  When there is no thread to watch (i.e. all threads are dead), the daemon thread
 * will terminate itself, and a new daemon thread will be started again when a new watch is added.
 * </p>
 *
 * @deprecated will be removed in the next major release
 */
@Deprecated
public final class ThreadDeathWatcher {

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(ThreadDeathWatcher.class);
    // visible for testing
    static final ThreadFactory threadFactory;

    // Use a MPMC queue as we may end up checking isEmpty() from multiple threads which may not be allowed to do
    // concurrently depending on the implementation of it in a MPSC queue.
    private static final Queue<Entry> pendingEntries = new ConcurrentLinkedQueue<Entry>();
    private static final Watcher watcher = new Watcher();
    private static final AtomicBoolean started = new AtomicBoolean();
    private static volatile Thread watcherThread;

    static {
// ... (201 more lines)