svn: r6897

collects/htdch/draw/Makefile

@@ -0,0 +1,19 @@
+DRAW = /Users/matthias/plt/collects/htdch/
+
+FILES = \
+  World \
+  Canvas
+
+doc: 
+	javadoc -classpath $(DRAW) $(addsuffix .java, $(FILES)) -d docs -breakiterator
+
+compile: 
+
+run: 
+
+test: 
+
+clean: 
+	rm -rf *~ *.class docs/
+
+

collects/htdch/draw/World.java

@@ -2,6 +2,14 @@ package draw;
         
 public abstract class World {
     protected Canvas theCanvas;
+    
+    /** 
+     *@author Matthias Felleisen, Kathy Gray 
+     *@param width positive int, the width of the visible canvas 
+     *@param height positive int, the height of the visible canvas 
+     *@param s positive double, the rate at which the clock ticks per second 
+     *@return true if the world is created without obstacle 
+     */ 
     public boolean bigBang(int width, int height, double s) {
 	if (width <= 0)
            throw new RuntimeException(
@@ -20,15 +28,51 @@ public abstract class World {
 		       + s);
 	theCanvas = new Canvas(width,height); 
 	return bigBangO(s);
- };
- private native boolean bigBangO(double s);
+    };
+    private native boolean bigBangO(double s);
 
- // --------------------------------------------------------    
+    // --------------------------------------------------------    
 
- public native boolean endOfTime(String s);
- public native World endOfWorld(String s);
- public abstract World onTick();
- public abstract World onKeyEvent(String ke); 
- public abstract boolean draw();
- public abstract boolean erase();
+    /**
+     *@param s is the message to be displayed 
+     *@return true, if it succeeds in stopping the clock and displaying the message
+     *After the end of time, events no longer trigger calls
+     *to onTick or onKeyEvent (see below). The canvas remains visible. 
+     */
+    public native boolean endOfTime(String s);
+
+    /**
+     *@param s is the message to be displayed 
+     *@return the last World, if it succeeds in stopping the clock and displaying the message
+     *After the end of the world, events no longer trigger calls
+     *to onTick or onKeyEvent (see below). The canvas remains visible. 
+     */
+    public native World endOfWorld(String s);
+
+    /**
+     *@return the new world 
+     *The method is invoked for every tick of the clock. Its purpose is to create a 
+     * World whose differences with this one represent what happened during the amount 
+     * of time it takes the clock to tick. 
+     */
+    public abstract World onTick();
+
+    /** 
+     *@param ke the String representing the key that was pressed
+     *@return the new world
+     *The method is invoked for every keyboard event associated with the canvas. 
+     * Its purposes is to create a World whose differences with this one represent
+     * what happens due to the user's use of the keyboard. 
+     */
+    public abstract World onKeyEvent(String ke); 
+
+    /**
+     *@return true, if the method succeeds in printing this world ('s canvas)
+     */
+    public abstract boolean draw();
+
+    /**
+     *@return true, if the method succeeds in erasing this world ('s canvas)
+     */
+    public abstract boolean erase();
 }