gistfile1.txt

/*
 * Copyright (C) 2010 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.crsh;

import org.crsh.term.Term;
import org.crsh.term.TermEvent;

import java.io.IOException;
import java.util.concurrent.PriorityBlockingQueue;

/**
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 */
public class EventQueue {

  /** . */
  private final Term term;

  /** . */
  private final PriorityBlockingQueue<TermEvent> queue;

  /** . */
  private Thread thread;

  /** . */
  private final Object lock;

  /** . */
  private volatile boolean priorityMode;

  /** . */
  private volatile boolean done;

  public EventQueue(Term term) {
    this.term = term;
    this.queue = new PriorityBlockingQueue<TermEvent>(10);
    this.lock = new Object();
    this.priorityMode = false;
    this.done = false;
  }

  public void start() {
    if (thread != null) {
      throw new IllegalStateException();
    }
    this.thread = new Thread() {
      @Override
      public void run() {
        while (!done) {
          try {
            TermEvent event = term.read();
            queue.add(event);
            synchronized (lock) {
              lock.notifyAll();
            }
          } catch (IOException e) {
            e.printStackTrace();
          }
        }
      }
    };
    this.thread.start();
  }

  public void stop() {
    if (thread != null) {
      done = true;
      term.close();
    }
  }

  public int getSize() {
    return queue.size();
  }

  public void setPriorityMode(boolean value) {
    this.priorityMode = value;
    synchronized (lock) {
      lock.notifyAll();
    }
  }

  public TermEvent next() throws InterruptedException {
    while (true) {
      if (priorityMode) {
        TermEvent event = queue.take();
        if (event instanceof TermEvent.Break || event instanceof TermEvent.Close) {
          return event;
        } else {
          queue.add(event);
          synchronized (lock) {
            lock.wait();
          }
        }
      } else {
        return queue.take();
      }
    }
  }
}