/*
 * Copyright (c) 2007, Swedish Institute of Computer Science. All rights
 * reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer. 2. Redistributions in
 * binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other
 * materials provided with the distribution. 3. Neither the name of the
 * Institute nor the names of its contributors may be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * $Id: RadioMediumEventpoint.java,v 1.1 2007/08/21 14:39:58 fros4943 Exp $
 */

package se.sics.chakana.eventpoints;

import java.util.Observable;
import java.util.Observer;

import se.sics.cooja.RadioMedium;

/**
 * Triggers if radio medium changes
 *
 * @author Fredrik Osterlind
 */
public class RadioMediumEventpoint implements Eventpoint {
  protected boolean shouldBreak = false;
  private int myID = 0;
  protected RadioMedium radioMedium;
  private int count = 1;
  
  public RadioMediumEventpoint(RadioMedium radioMedium) {
    if (radioMedium == null) {
      // TODO Throw exception
      return;
    }
    
    this.radioMedium = radioMedium;
    
    // Register as radio medium observer
    radioMedium.addRadioMediumObserver(new Observer() {
      public void update(Observable obs, Object obj) {
        handleRadioMediumChange();
      }
    });
  }
  
  public RadioMediumEventpoint(RadioMedium radioMedium, int count) {
    this(radioMedium);
    this.count = count;
  }

  protected void handleRadioMediumChange() {
    count--;
    if (count < 1)
      shouldBreak = true;
  }
  
  public String getMessage() {
    return "Radio medium changed";
  }

  public boolean evaluate() {
    return shouldBreak;
  }
  
  public void setID(int id) {
    myID = id;
  }

  public int getID() {
    return myID;
  }
}
