corejava第10版

corejava第10版/v1ch14/bounceThread/BallComponent.java

@@ -0,0 +1,38 @@
+package bounceThread;
+
+import java.awt.*;
+import java.util.*;
+import javax.swing.*;
+
+/**
+ * The component that draws the balls.
+ * @version 1.34 2012-01-26
+ * @author Cay Horstmann
+ */
+public class BallComponent extends JComponent
+{
+   private static final int DEFAULT_WIDTH = 450;
+   private static final int DEFAULT_HEIGHT = 350;
+
+   private java.util.List<Ball> balls = new ArrayList<>();
+
+   /**
+    * Add a ball to the panel.
+    * @param b the ball to add
+    */
+   public void add(Ball b)
+   {
+      balls.add(b);
+   }
+
+   public void paintComponent(Graphics g)
+   {
+      Graphics2D g2 = (Graphics2D) g;
+      for (Ball b : balls)
+      {
+         g2.fill(b.getShape());
+      }
+   }
+   
+   public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
+}