cycles.java

java编程思想第四版习题答案

// interfaces/Cycles.java
// TIJ4 Chapter Interfaces, Exercise 18, page 342
/* Create a Cycle interface, with implementations Unicycle, Bicycle and
* Tricycle. Create factories for each type of Cycle, and code that uses
* these factories.
*/

import static org.greggordon.tools.Print.*;

interface Cycle {
	void ride();
}

interface CycleFactory {
	Cycle getCycle();
}

class Unicycle implements Cycle {
	public void ride() { println("Ride Unicycle"); }
}

class UnicycleFactory implements CycleFactory {
	public Cycle getCycle() {
		return new Unicycle();
	}
}

class Bicycle implements Cycle {
	public void ride() { println("Ride Bicycle"); }
}

class BicycleFactory implements CycleFactory {
	public Cycle getCycle() {
		return new Bicycle();
	}
}


class Tricycle implements Cycle {
	Tricycle() { println("Tricycle()"); }
	public void ride() { println("Ride Tricycle"); }
}

class TricycleFactory implements CycleFactory {
	public Cycle getCycle() {
		return new Tricycle();
	}
}

public class Cycles {
	public static void rideCycle(CycleFactory factory) {
		Cycle c = factory.getCycle();
		c.ride();
	}
	public static void main(String [] args) {
		rideCycle(new UnicycleFactory());
		rideCycle(new BicycleFactory());
		rideCycle(new TricycleFactory());
	}
}