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Semester 1/Programming 1/Java/examples/projects/chapter06/bouncing-balls/BallDemo.java

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+import java.awt.Color;
+
+/**
+ * Class BallDemo - a short demonstration showing animation with the 
+ * Canvas class. 
+ *
+ * @author Michael Kölling and David J. Barnes
+ * @version 2016.02.29
+ */
+
+public class BallDemo   
+{
+    private Canvas myCanvas;
+
+    /**
+     * Create a BallDemo object. Creates a fresh canvas and makes it visible.
+     */
+    public BallDemo()
+    {
+        myCanvas = new Canvas("Ball Demo", 600, 500);
+    }
+
+    /**
+     * Simulate two bouncing balls
+     */
+    public void bounce()
+    {
+        int ground = 400;   // position of the ground line
+
+        myCanvas.setVisible(true);
+
+        // draw the ground
+        myCanvas.setForegroundColor(Color.BLACK);
+        myCanvas.drawLine(50, ground, 550, ground);
+
+        // create and show the balls
+        BouncingBall ball = new BouncingBall(50, 50, 16, Color.BLUE, ground, myCanvas);
+        ball.draw();
+        BouncingBall ball2 = new BouncingBall(70, 80, 20, Color.RED, ground, myCanvas);
+        ball2.draw();
+
+        // make them bounce
+        boolean finished =  false;
+        while (!finished) {
+            myCanvas.wait(50);           // small delay
+            ball.move();
+            ball2.move();
+            // stop once ball has travelled a certain distance on x axis
+            if(ball.getXPosition() >= 550 || ball2.getXPosition() >= 550) {
+                finished = true;
+            }
+        }
+    }
+}