[原]简单工厂模式

[关键字]:java,设计模式,简单工厂,《java与模式》
[环境]:StarUML + JDK6
[作者]:Winty ([e-mail])
    简单工厂模式：


 
    代码:

/**
 *简单工厂测试
 *@version 2009-3-25
 *@author Winty([e-mail])
 */
package pattern.simplefactory;

public class SimpleFactory{
    public static void main(String[] args){
        Shape shape;

        try{
            shape = ArtTracer.factory("circle");
            shape.draw();
            shape.erase();

            shape = ArtTracer.factory("square");
            shape.draw();
            shape.erase();

            shape = ArtTracer.factory("triangle");
            shape.draw();
            shape.erase();

            //未知图形类型
            shape = ArtTracer.factory("unknownShape");
            shape.draw();
            shape.erase();
        }catch(BadShapeException e){
            System.out.println(e.getMessage());
        }
    }
}

/**
 *简单工厂:绘图员
 */
class ArtTracer{
    public static Shape factory(String type)throws BadShapeException{
        if(type.equalsIgnoreCase("Circle")){
            return new Circle();
        }else if(type.equalsIgnoreCase("Square")){
            return new Square();
        }else if(type.equalsIgnoreCase("Triangle")){
            return new Triangle();
        }else{
            throw new BadShapeException(type);
        }
    }
}

/**
 *抽象产品
 */
abstract class Shape{
    public abstract void draw();
    public abstract void erase();
}

/**
 *具体产品
 */
class Circle extends Shape{
   
    public void draw(){
        System.out.println("Circle draw");
    }

   
    public void erase(){
        System.out.println("Circle erase");
    }
}

/**
 *具体产品
 */
class Square extends Shape{
   
    public void draw(){
        System.out.println("Square draw");
    }

   
    public void erase(){
        System.out.println("Square erase");
    }
}

/**
 *具体产品
 */
class Triangle extends Shape{
   
    public void draw(){
        System.out.println("Triangle draw");
    }

   
    public void erase(){
        System.out.println("Triangle erase");
    }
}

/**
 *辅助类:当输入的类为不支持的图形时，抛出异常
 */
class BadShapeException extends Exception{
    public BadShapeException(String type){
        super(type + ":不支持的图形");
    }
}