---

Abstract Classes

• Factor out common behavior
  (setSelected, isSelected)
• Subclasses inherit common behavior
  
• Some methods still undefined
  (draw, drawSelection, translate, contains)

public class SelectableShape implements Item 
{ 
   public void setSelected(boolean b) { selected = b; } 
   public boolean isSelected() { return selected; }
   private boolean selected; 
} 

---

previous | start | next .... [Slide 30] ....