创建型模式之原型模式PROTOTYPE

川长思鸟来 2021-09-11 05:54 340阅读 0赞

![这里写图片描述][SouthEast]  
意图：用原型实例指定创建对象的种类，并且通过拷贝这些原型创建新的对象。

## **一、原型模式** ##

原型模式应用场景主要在于当一个对象的创建非常复杂，消耗很多资源之时。如果一个对象的创建之前需要经过很过步骤和要求，一般情况对象用完就会销毁。但为了避免资源的消耗。可以把对象存住，下次使用时直接复制原型。  
[java 克隆][java]  
![这里写图片描述][SouthEast 1]

## **二、代码** ##

**原料**  
主要在于实现java对象的克隆

package prototype;
    
    public abstract class Shape implements Cloneable { 
    
           private String id;
           protected String type;
    
           abstract void draw();
    
           public void setId(String id){
               this.id = id;
           }
    
           public String getId() {
                  return id;
           }       
    
           public Object clone() {
               Shape clone = null;
              try {
                 clone = (Shape)super.clone();
              } catch (CloneNotSupportedException e) {
                 e.printStackTrace();
              }
              return clone;
           }
    }

package prototype;
    
    public class Rectangle extends Shape{ 
    
        public Rectangle(){
            type = "Rectangle";
        }
    
       @Override
       public void draw() {
          System.out.println("Rectangle");
       }
    
    }

package prototype;
    
    public class Square extends Shape { 
    
       public Square(){
             type = "Square";
       }
    
       @Override
       public void draw() {
          System.out.println("Square");
       }
    
    }

**容器**

package prototype;
    
    import java.util.Hashtable;
    
    public class ShapeCache {
       private static Hashtable<String, Shape> shapeMap 
          = new Hashtable<String, Shape>();
    
       public static Shape getShape(String shapeId) {
          Shape cachedShape = shapeMap.get(shapeId);
          return (Shape) cachedShape.clone();
       }
    
    
       public static void loadCache() {
    
          Square square = new Square();
          square.setId("1");
          shapeMap.put(square.getId(),square);
    
          Rectangle rectangle = new Rectangle();
          rectangle.setId("2");
          shapeMap.put(rectangle.getId(),rectangle);
    
       }
    
       public static void main(String[] args) {
              ShapeCache.loadCache();
    
              Shape clonedShape1 = (Shape) ShapeCache.getShape("1");
              System.out.println(clonedShape1.type);        
    
              Shape clonedShape2 = (Shape) ShapeCache.getShape("2");
              System.out.println(clonedShape2.type);        
    
        }   
    
    }

[代码][Link 1]

[SouthEast]: /images/20210520/d21e296deba943bf93add7a8ba7e69b7.png
[java]: http://blog.csdn.net/qq_16234613/article/details/53996278
[SouthEast 1]: /images/20210520/bec71d8d950d4e0da1b8761b62016228.png
[Link 1]: http://download.csdn.net/detail/qq_16234613/9729533