1 package G4ip;

     2 

     3 import pizza.util.Hashtable;

     4 import java.awt.*;

     5 import G4ip.Form.*;

     6 

     7 

     8 /** A label with a surrounding box.

     9   */

    10 class MyLabel extends Label {

    11   public MyLabel() { super(); }

    12   public MyLabel(String s) { super(s); }

    13 

    14   public void paint(Graphics g) {

    15     Dimension d = this.size();

    16     g.setColor(Color.gray);

    17     g.drawRect(0,0,d.width-1,d.height-1);

    18   }

    19 }

    20 

    21 

    22 /** Draws a frame on the screen containing a proof.

    23   */

    24 public class ProofDisplay extends Frame {

    25   Button ok;

    26   Hashtable<int,Sequent> proof;      // contains the indexed sequents 

    27 

    28   /** The proof is represented in the hashtable.

    29     * @param proof is a hashtable; the structure of the proof (or tree) 

    30     * is mapped onto a sequence of integers; each integer is a key for

    31     * a sequent stored in the hashtable.

    32     */

    33   public ProofDisplay(Hashtable<int,Sequent> iproof) {

    34     super("Proof");

    35     ok = new Button("Close");

    36     proof = iproof;

    37 

    38     setLayout(new BorderLayout());

    39     // SOUTH

    40     Panel p = new Panel();

    41     p.add(ok);

    42     add("South",p);

    43 

    44     //CENTER

    45     Panel display = new Panel();

    46     printproof(display,1);

    47     add("Center", display);

    48 

    49     pack();

    50     show();

    51   }

    52 

    53   /** Recovers the structure of the proofs from the hashtable representation.

    54     */

    55   public void printproof(Panel p,int index) {

    56     MyLabel l = new MyLabel(proof.get(index).toString());

    57     l.setAlignment(MyLabel.CENTER);

    58     p.setLayout(new BorderLayout());

    59     p.add("South",l); 

    60     // axiom (do nothing)

    61     if ((proof.get(2*index) == null) && (proof.get(2*index+1) == null)) { 

    62       return;    

    63     }

    64     // rule with a single premise

    65     if ((proof.get(2*index) != null) && (proof.get(2*index+1) == null)) { 

    66       Panel np = new Panel();

    67       printproof(np,2*index);

    68       p.add("Center",np);

    69       return;  

    70     }

    71     // rule with two premises

    72     if ((proof.get(2*index) != null) && (proof.get(2*index+1) != null)) { 

    73       Panel np1 = new Panel();

    74       Panel np2 = new Panel();

    75       printproof(np1,2*index);

    76       printproof(np2,2*index+1);

    77       p.add("West",np1);

    78       p.add("East",np2);

    79       return;

    80     }

    81     

    82   }

    83 

    84   /** If either the "Close" or the "Window-destroy" button

    85     * is pressed, then close the window.

    86     */

    87   public boolean handleEvent(Event e)  {

    88     if (e.id == Event.ACTION_EVENT && e.target == ok) {

    89       this.finalize(); 

    90       return true;

    91     }

    92     if (e.id == Event.WINDOW_DESTROY) {

    93       this.finalize(); 

    94       return true;

    95     }

    96     return false;

    97   }

    98 

    99   /** Closes the window.

   100     */

   101   public void finalize()

   102     { this.dispose();  }

   103   

   104 }

   105 

   106