import java.awt.*; public abstract class PhysicsElement { private final int myId; /* to identify each element within its category */ protected PhysicsElement( int id){ myId = id; } protected int getId() { return myId; } public abstract String getDescription(); public abstract String getState(); public abstract void updateView(Graphics2D g); public abstract boolean contains(double x, double y); public abstract void setSelected(); public abstract void setReleased(); public abstract void dragTo(double x); }