com.brienwheeler.lib.concurrent.NamedThreadFactory.java Source code

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Here is the source code for com.brienwheeler.lib.concurrent.NamedThreadFactory.java

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/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2013 Brien L. Wheeler (brienwheeler@yahoo.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.brienwheeler.lib.concurrent;

import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Required;

import com.brienwheeler.lib.util.ValidationUtils;

/**
 * A {@link ThreadFactory} that creates threads belonging to a single parent {@link ThreadGroup}
 * and names each thread <i>name-count</i> where <i>name</i> is the value passed to setName() and
 * <i>count</i> is an increasing index for this NamedThreadFactory.
 * <br/>
 * <br/>
 * setName() must be called before newThread() or getThreadGroup() or an {@link IllegalStateException} will be thrown
 * <br/>
 * setName() cannot be called more than once  or an {@link IllegalStateException} will be thrown
 * <br/>
 * Also enforces the best practice of using an UncaughtExceptionHandler on each thread pool thread.  The default
 * uncaught exception handler simply logs the exception.
 * 
 * @author bwheeler
 */
public class NamedThreadFactory implements ThreadFactory {
    private static final Log log = LogFactory.getLog(NamedThreadFactory.class);

    protected final AtomicInteger threadCount = new AtomicInteger();
    protected final AtomicReference<ThreadGroup> threadGroup = new AtomicReference<ThreadGroup>();
    protected final AtomicReference<Thread.UncaughtExceptionHandler> uncaughtExceptionHandler = new AtomicReference<Thread.UncaughtExceptionHandler>(
            new UncaughtExceptionHandler());

    public NamedThreadFactory() {
    }

    public NamedThreadFactory(String name) {
        setName(name);
    }

    @Override
    public Thread newThread(Runnable target) {
        ThreadGroup threadGroup = this.threadGroup.get();
        if (threadGroup == null)
            throw new IllegalStateException(
                    "not allowed to call newThread() before calling setName() on " + getClass().getSimpleName());

        log.debug("allocating new thread in " + getName());
        Thread thread = new Thread(threadGroup, target,
                threadGroup.getName() + "-" + threadCount.incrementAndGet());
        thread.setUncaughtExceptionHandler(uncaughtExceptionHandler.get());
        return thread;
    }

    public String getName() {
        ThreadGroup threadGroup = this.threadGroup.get();
        if (threadGroup == null)
            throw new IllegalStateException(
                    "not allowed to call getName() before calling setName() on " + getClass().getSimpleName());
        return threadGroup.getName();
    }

    @Required
    public void setName(String name) {
        ValidationUtils.assertNotNull(name, "name cannot be null");

        ThreadGroup threadGroup = new ThreadGroup(name);
        if (!this.threadGroup.compareAndSet(null, threadGroup))
            throw new IllegalStateException("not allowed to rename " + getClass().getSimpleName());
    }

    public ThreadGroup getThreadGroup() {
        ThreadGroup threadGroup = this.threadGroup.get();
        if (threadGroup == null)
            throw new IllegalStateException("not allowed to call getThreadGroup() before calling setName() on "
                    + getClass().getSimpleName());
        return threadGroup;
    }

    public void setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler uncaughtExceptionHandler) {
        this.uncaughtExceptionHandler.set(uncaughtExceptionHandler);
    }

}