Re-adding Topics to SVN

java/examples/Topics/Advanced Data/ArrayListClass/ArrayListClass.pde

@@ -0,0 +1,52 @@
+/**
+ * ArrayList of objects
+ * by Daniel Shiffman.  
+ * 
+ * This example demonstrates how to use a Java ArrayList to store 
+ * a variable number of objects.  Items can be added and removed
+ * from the ArrayList.
+ *
+ * Click the mouse to add bouncing balls.
+ */
+
+ArrayList balls;
+int ballWidth = 48;
+
+void setup() {
+  size(640, 360);
+  smooth();
+  noStroke();
+
+  // Create an empty ArrayList
+  balls = new ArrayList();
+  
+  // Start by adding one element
+  balls.add(new Ball(width/2, 0, ballWidth));
+}
+
+void draw() {
+  background(255);
+
+  // With an array, we say balls.length, with an ArrayList, we say balls.size()
+  // The length of an ArrayList is dynamic
+  // Notice how we are looping through the ArrayList backwards
+  // This is because we are deleting elements from the list  
+  for (int i = balls.size()-1; i >= 0; i--) { 
+    // An ArrayList doesn't know what it is storing so we have to cast the object coming out
+    Ball ball = (Ball) balls.get(i);
+    ball.move();
+    ball.display();
+    if (ball.finished()) {
+      // Items can be deleted with remove()
+      balls.remove(i);
+    }
+    
+  }  
+  
+}
+
+void mousePressed() {
+  // A new ball object is added to the ArrayList (by default to the end)
+  balls.add(new Ball(mouseX, mouseY, ballWidth));
+}
+