drawmodel.java

简单的画图程序

package boya;
import java.io.*;
import java.util.*;
class DrawModel extends Observable implements Serializable{
 protected LinkedList elements=new LinkedList();
 public void add(Elements element){
  elements.add(element);
  setChanged();
  notifyObservers(element.getBounds());
 }
 public boolean remove(Elements element){
  boolean removed=elements.remove(element);
  if(removed){
   setChanged();
   notifyObservers(element.getBounds());
  }
  return removed;
 }
 public Iterator getIterator(){
  return elements.listIterator();
 }
}