/*   
 * File: Radio.java
 */

/**
 * This package contains the files that support the GUI
 * assignment for Semester 2 - 2000
 */
package gui2000;

import java.util.*;

/**
 * The <code>Radio</code> simulates radio contact with all the aircraft in 
 * a particular simulated airspace. 
 * 
 * @author T Balls  
 * @version 0.1, 12-12-99
 *                
 * @see gui2000.AirSpace
 */
 
public class Radio extends java.util.Observable
                implements java.util.Observer
{  public Radio( Vector theAircraft )
   {  aircraft = theAircraft; 
   }
   
   /**@shapeType AggregationLink
   @associates <b>Aircraft</b>*/ 
   private Vector aircraft = null;                           
   
   /**
    * Called by each <code>Aircraft</code> when there is a message
    * to pass to the air traffic controller.
    * <P>
    * The method prepends the call sign to the message before passing
    * it to any Observers registered.
    */
   public void update( Observable o, Object message )
   {  if( (o instanceof Aircraft) && (message instanceof String) )
      {  setChanged();
         notifyObservers( ((Aircraft)o).getData().callSign + ": " + message );
      }
   }  
   
   /**
    * Send a message to an aircraft
    * <P> 
    * @param callsign - the aircraft's call sign (squawk code)
    * @param message the String to be sent to the aircraft
    */
   public void broadcast( String callsign, String message )
   {  for( int i = 0; i < aircraft.size(); i++ )
      {  Aircraft theOne = (Aircraft)(aircraft.elementAt(i));   
         if( theOne.getData().callSign.equals( callsign ) )
         {  theOne.order( message );    
            return;
         }
      } 
   }
}