org.guzz.util.thread.DemonQueuedThread.java Source code

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Here is the source code for org.guzz.util.thread.DemonQueuedThread.java

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/*
 * Copyright 2008-2009 the original author or authors.
 *
 * Licensed 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.guzz.util.thread;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.guzz.service.core.DebugService;

/**
 * 
 * A demon thread holding a queue. When the queue is full, new arrived objects override the oldest one.
 * <p />The queue is not thread-safe, and doesn't guarantee that no data will lose. Objects in this queue is processed randomly.
 *
 * @author liukaixuan(liukaixuan@gmail.com)
 */
public class DemonQueuedThread extends Thread {
    private transient final Log log = LogFactory.getLog(getClass());

    private boolean keepRunning = true;

    private String threadName;

    protected Object[] queues;

    private volatile int currentWritePos = 0;

    private boolean isSleepNow = false;

    private int millSecondsToSleep = 500;

    public boolean isSleeping() {
        return isSleepNow;
    }

    public void addToQueue(Object obj) {
        int pos = currentWritePos++;
        if (pos >= queues.length) {
            currentWritePos = 0;
            pos = 0;
        }

        queues[pos] = obj;
    }

    public DemonQueuedThread(String threadName, int queueSize) {
        this.setDaemon(true);
        this.threadName = threadName;
        this.queues = new Object[queueSize];

        this.setName(DebugService.DEMON_NAME_PREFIX + threadName);
    }

    public void shutdown() {
        this.keepRunning = false;

        try {
            this.notify();
        } catch (Exception e) {
        }

        log.info("thread [" + threadName + "] closed.");
    }

    /**
     * 
     * @return should keep the thread running.
     */
    protected boolean doWithTheQueue() throws Exception {
        return true;
    }

    public void run() {
        while (keepRunning) {
            isSleepNow = false;

            boolean shouldSleep = true;

            try {
                shouldSleep = !doWithTheQueue();

            } catch (Throwable e) {
                shouldSleep = true;
                //ignore all errors
                log.error("error occured whiling processing the queue of thread: " + this.threadName, e);
            }

            if (shouldSleep) {
                try {
                    synchronized (this) {
                        isSleepNow = true;
                        this.wait(getMillSecondsToSleep());
                    }
                } catch (Throwable e) {
                    //ignore all errors
                }
            }
        }
    }

    protected int getMillSecondsToSleep() {
        return this.millSecondsToSleep;
    }

    public void setMillSecondsToSleep(int millSecondsToSleep) {
        this.millSecondsToSleep = millSecondsToSleep;
    }

}