// this version works with Java 1.0 (e.g. VJ++ 1.1)
// oct-16-1998
import java.awt.*;
import java.applet.*;
import java.util.*;
import Set;
public class SetAppletV10 //extends Frame  // use Frame for stand-alone
                       extends Applet      // use Applet for applet
{
/**
   public static void main(String[] argv)   // use main for stand-alone
   {
	   Frame f = new SetAppletV10();
	   f.resize(400,300);
	   f.show();
   } // main
**/

   public void init()                      // use init for applet
//   public SetAppletV10()                 // use constructor for stand-alone
   {
      set1 = new Set();
      set2 = new Set();

      // components
      setLayout(new BorderLayout());

      // checkbox group
      selectorGroup = new CheckboxGroup();
      // checkboxes
      set1Selector = new Checkbox("Set 1",selectorGroup,true);
      set2Selector = new Checkbox("Set 2",selectorGroup,false);
      set1Selector.setCheckboxGroup(selectorGroup);
      set2Selector.setCheckboxGroup(selectorGroup);
      Panel p = new Panel();
      p.add(set1Selector);
      p.add(set2Selector);
      add("North", p);

      // lists
      set1List = new List();
      set1List.setBackground(Color.white);
      set2List = new List();
      set2List.setBackground(Color.white);
      resultList = new List();
      resultList.setBackground(Color.white);
      p = new Panel();
      p.add(new Label("Set1"));
      p.add(set1List);
      p.add(new Label("Set2"));
      p.add(set2List);
      p.add(new Label("Result"));
      p.add(resultList);
      add("Center", p);

      // buttons
      add = new Button("Add:");
      value = new TextField(5);
      clear = new Button("Clear");
      union = new Button("Union");
      intersect = new Button("Intersect");
      p = new Panel();
      p.add(add);
      p.add(value);
      p.add(clear);
      p.add(union);
      p.add(intersect);
      add("South", p);
   
      // set active Checkbox
      activeSet = set1;
      activeList = set1List;
   } // init

   // handles actions generated by buttons and checkboxes

   public boolean handleEvent(Event evt)
   {
	   if (evt.id == Event.WINDOW_DESTROY)
		   System.exit(0);
	   return super.handleEvent(evt);
   } // handleEvent

   public boolean action(Event ae, Object arg)
   {
       if (ae.target.equals(add))
       {
         addElement();
         repaint();
       }
       else if (ae.target.equals(union)) // union two sets
          loadResult(set1.union(set2));
       else if (ae.target.equals(intersect))
          loadResult(set1.intersection(set2));
       else if (ae.target.equals(clear))
       {
          activeSet.removeAllElements();
          activeList.clear();
       }
       else if (ae.target.equals(set1Selector))
       {
          activeList = set1List;
          activeSet  = set1;
       } 
       else if (ae.target.equals(set2Selector))
       {
          activeList = set2List;
          activeSet  = set2;
       } 
       else return super.action(ae,arg);
       return true;
   } // action

   private void addElement()
   {
      int i = Integer.parseInt(value.getText());
      activeSet.addElement(new Integer(i));  // ours is an Integer set
      activeList.addItem(Integer.toString(i));  // list only takes String
   } // addElement

   private void loadResult(Set resultSet)
   {
      resultList.clear();
      Enumeration e = resultSet.elements();
      while (e.hasMoreElements())
         resultList.addItem(e.nextElement().toString());
      repaint();
   }

   // instance variables
   Button add, union, intersect, clear;
   List set1List, set2List, activeList, resultList;
   Checkbox set1Selector, set2Selector;
   CheckboxGroup selectorGroup;
   TextField value;
   Set set1, set2, activeSet;
} // SetApplet