// Model.java adapted by Dr. I. for CS 102 during Spring, 2003
// Simple model class for Model-View-Controller

import java.util.Observable;

public class Model extends Observable {

   // model data value
   private int value = 0;

   // model constructor
   public Model(int data) {
      changeValue(data);
   }

   // change value and notify observers of change
   private void changeValue(int change) {
      value += change;

      // must call setChanged before notifyObservers to
      // indicate model has changed
      setChanged();

      // notify Observers that model has changed
      notifyObservers();
   }

   // increment data value
   public void incrementValue(int amount) {

      // increment data value by amount
      changeValue(amount);
   }

   // decrement data value
   public void decrementValue(int amount) {

      // decrement data value by amount
      changeValue(-amount);
   }

   // get data value
   public int getValue() {
      return value;
   }
}