public class RadarSimulator {

	public static void main(String[] args) {

		Vehicle v  = new Ferrari();
		v = new RadarDetecting(v);

		v.setSpeed(100);

		RadarTrap r = new RadarTrap();
		r.enter(v);
		r.checkForSpeeders();
	}
}

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import java.util.Iterator;

public class RadarTrap {

	private int SPEED_LIMIT = 65;
	private List<Vehicle> vehicles = new SinglyLinkedList<Vehicle>();

	public void enter(Vehicle v) {
		vehicles.add(v);
	}

	public int measureSpeed(Vehicle v) {
		v.illuminated(this);
		return v.getSpeed();
	}

	public void checkForSpeeders() {

		Iterator<Vehicle> it = vehicles.iterator();

		while (it.hasNext()) {
			Vehicle v = it.next();
			if (measureSpeed(v) > SPEED_LIMIT) {
				v.getTicketed();
			}
		}
	}
}

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public abstract class Vehicle {

	RadarBehavior radarBehavior;

	int speed = 0;

	public int getSpeed() {
		return speed;
	}

	public void setSpeed(int speed) {
		this.speed = speed;
	}

	public void getTicketed() {
		System.out.println("Ticket");
	}

	public void illuminated(RadarTrap radarTrap) {
		System.out.println("Illuminated");
	}
}

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public class Ferrari extends Vehicle {

	public Ferrari() {
		radarBehavior = new DoNothing();
	}
}

------------------------------------------------

public class RadarDetecting extends Decorator {

	Vehicle vehicle;

	public RadarDetecting(Vehicle vehicle) {
		this.vehicle = vehicle;
	}

	public int getSpeed() {
		return speed;
	}

	public void illuminated(RadarTrap radarTrap) {
		System.out.println("Got illuminated, so slowed down..");
		this.setSpeed(60);
	}
}