// This example is from the book Developing Java Beans by Robert Englander. 
// Copyright (c) 1997 O'Reilly & Associates.
// You may study, use, modify, and distribute this example for any purpose.
// This example is provided WITHOUT WARRANTY either expressed or implied.

// Chapter 8 -- The Boiler class

package BeansBook.Simulator;

import java.awt.*;
import java.beans.*;

// the Boiler bean class definition
public class Boiler extends TemperatureModifier  // subclasses TemperatureModifier
   implements HeatingRequestListener,   // listens for heating requests 
              VetoableChangeListener    // vetoes property changes
{
   // constructor
   public Boiler()
   {
      // a boiler is a temperature modifier that operates at
      // 100 degress celsius
      super(100.0, "BOILER ON", "BOILER OFF",
               Color.red, Color.yellow);
   }
   
   // handle a heating request event
   public void heatingRequest(ServiceRequestEvent evt)
   {
      // set the Running property based on the value returned
      // by the isStart method from the event
      setRunning(evt.isStart());
   }
   
   // handle a vetoable change event
   public void vetoableChange(PropertyChangeEvent evt)
           throws PropertyVetoException
   {
      // only interested in ComfortTemperature
      if (evt.getPropertyName().equals("ComfortTemperature"))
      {
         // get the proposed temperature
         Double d = (Double)evt.getNewValue();
         
         // veto a temperature over 100 degrees Celsius
         if (d.doubleValue() > 100.0)
         {
            throw new PropertyVetoException("Invalid Comfort Temperature", evt);
         }
      }
   }
}