原型模式

package com.chengjie;

import java.util.HashMap;

abstract class Shape implements Cloneable {

    private String id;
    protected String type;

    abstract void draw();

    public String getType() {
        return type;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public Object clone() {
        Object clone = null;
        try {
            clone = super.clone();
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        return clone;
    }
}

class Rectangle extends Shape {

    public Rectangle() {
        type = "Rectangle";
    }

    @Override
    public void draw() {
        System.out.println("Inside Rectangle::draw() method.");
    }
}

class Square extends Shape {

    public Square() {
        type = "Square";
    }

    @Override
    public void draw() {
        System.out.println("Inside Square::draw() method.");
    }
}

class Circle extends Shape {

    public Circle() {
        type = "Circle";
    }

    @Override
    public void draw() {
        System.out.println("Inside Circle::draw() method.");
    }
}

class ShapeCache {
    private static HashMap<String, Shape> shapeMap = new HashMap<String, Shape>();

    public static Shape getShape(String id) {
        Shape shape = shapeMap.get(id);
        return (Shape) shape.clone();
    }

    public static void fill() {
        Circle circle = new Circle();
        circle.setId("1");
        shapeMap.put(circle.getId(), circle);

        Square square = new Square();
        square.setId("2");
        shapeMap.put(square.getId(), square);

        Rectangle rectangle = new Rectangle();
        rectangle.setId("3");
        shapeMap.put(rectangle.getId(), rectangle);
    }
}

public class TestPrototype {
    public static void main(String[] args) {
        ShapeCache.fill();
        Shape cloneShape = ShapeCache.getShape("1");
        System.out.println("Shape:" + cloneShape.getType());
        Shape clonedShape2 = (Shape) ShapeCache.getShape("2");
        System.out.println("Shape : " + clonedShape2.getType());
        Shape clonedShape3 = (Shape) ShapeCache.getShape("3");
        System.out.println("Shape : " + clonedShape3.getType());
    }
}