Heart.java

/*
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version. You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

package org.aitools.programd.util;

import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;

/**
 * A Heart beats. At a configurable interval, it calls pulse() methods on some objects (currently only the parent static
 * Multiplexor) in order to provide assurance that the bot server is alive.
 * 
 * @author <a href="mailto:noel@aitools.org">Noel Bush</a>
 */
public class Heart {

  class HeartBeat extends TimerTask {

    /**
     * @see java.util.TimerTask#run()
     */
    @Override
    public void run() {
      Heart.this.pulse();
    }
  }

  /** The Timer object used to beat the heart. */
  private Timer timer;

  /** The pulse rate. */
  private int _pulserate;

  /** Will hold a set of Pulses. */
  private ArrayList<Pulse> pulses = new ArrayList<Pulse>();

  /**
   * Creates a new Heart with the given pulse rate.
   * 
   * @param pulserate the pulse rate to use
   */
  public Heart(int pulserate) {
    this._pulserate = pulserate;
  }

  /**
   * Adds a Pulse to the registered list.
   * 
   * @param pulse the Pulse to be added
   */
  public void addPulse(Pulse pulse) {
    this.pulses.add(pulse);
  }

  /**
   * Emits any registered pulses.
   */
  public synchronized void pulse() {
    for (Pulse pulse : this.pulses) {
      pulse.emit();
    }
  }

  /**
   * Starts the heart (if the pulse is greater than zero).
   */
  public void start() {
    int pulse = 0;
    try {
      pulse = 60000 / this._pulserate;
    }
    catch (NumberFormatException e) {
      // Do nothing.
    }
    if (pulse > 0) {
      this.startBeating(pulse);
    }
  }

  /**
   * Starts the heart beating with a specified pulse.
   * 
   * @param pulse the period in milliseconds
   */
  protected void startBeating(int pulse) {
    this.timer = new Timer();
    this.timer.schedule(new HeartBeat(), 0, pulse);
  }
}