原型模式 -- 设计模式

原型模式（Prototype Pattern）是用于创建重复的对象，同时又能保证性能。

思考:  通过克隆的方式来创建重复的对象

package day0316.PrototypePattern;

import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.UUID;

public class PrototypePatternDemo{

    public static void main(String[] args) throws CloneNotSupportedException{
        System.out.println("============= EMULATE READING DATA FROM DATABASE ===============");
        ShapeCache.loadCache();

        Shape clonedShape = (Shape) ShapeCache.getShape("1");
        System.out.println("Shape : " + clonedShape.getType());

    }
}

class ShapeCache {

    static Map<String, Shape> shapeMap = new Hashtable<String, Shape>();

    static Shape getShape(String shapeId) throws CloneNotSupportedException{
        Shape cachedShape = shapeMap.get(shapeId);
        return (Shape) cachedShape.clone();
    }

    public static void loadCache() {

        Circle circle = new Circle("Circle " + UUID.randomUUID(), "Circle");
        System.out.println(circle);
        shapeMap.put(circle.getId(),circle);

        Square square = new Square("Square " + UUID.randomUUID(), "Square");
        System.out.println(square);
        shapeMap.put(square.getId(),square);

        Rectangle rectangle = new Rectangle("Rectangle " + UUID.randomUUID(), "Rectangle");
        System.out.println(rectangle);
        shapeMap.put(rectangle.getId(),rectangle);
    }

}

abstract class Shape implements Cloneable{

    String id;
    String type;

    public Shape(String id, String type){
        this.id = id;
        this.type = type;
    }

    public String getId(){
        return id;
    }

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

    public String getType(){
        return type;
    }

    public void setType(String type){
        this.type = type;
    }

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

    @Override
    public String toString(){
        String template = "[%s] ID: %s, TYPE: %s";
        return String.format(template, this.getClass().getName(), this.getId(), this.getType());
    }
}

class Circle extends Shape {

    public Circle(String id, String type){
        super(id, type);
    }

}


class Rectangle extends Shape {

    public Rectangle(String id, String type){
        super(id, type);
    }

}


class Square extends Shape {

    public Square(String id, String type){
        super(id, type);
    }

}