1.Simple Factory模式:
1、 在这里,我们先定义水果(Fruit)接口:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.simplefactory;
public
interface
Fruit
{
void
plant();
void
enableEat();
}
2、 苹果(Apple)是对水果(Fruit)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.simplefactory;
public
class
Apple
implements
Fruit
{
public
void
enableEat()
{
System.out.println(
"
苹果能吃啦
"
);
}
public
void
plant()
{
System.out.println(
"
种植苹果
"
);
}
}
3、 葡萄(Grape)是对水果(Fruit)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.simplefactory;
public
class
Grape
implements
Fruit
{
public
void
enableEat()
{
System.out.println(
"
葡萄能吃啦
"
);
}
public
void
plant()
{
System.out.println(
"
种植葡萄
"
);
}
}
4、 鸭梨(Pear)是对水果(Fruit)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.simplefactory;
public
class
Pear
implements
Fruit
{
public
void
enableEat()
{
System.out.println(
"
鸭梨能吃啦!
"
);
}
public
void
plant()
{
System.out.println(
"
种植鸭梨
"
);
}
}
5、定义买水果工厂(FruitFactory)这一过程类:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.simplefactory;
public
class
FruitFactory
{
/**
* 种植水果
*
*
@param
str
*
@return
*/
public
static
Fruit plantFruit(String str)
{
str
=
str.toLowerCase();
if
(str.equals(
"
apple
"
))
return
new
Apple();
if
(str.equals(
"
grape
"
))
return
new
Grape();
if
(str.equals(
"
pear
"
))
return
new
Pear();
return
null
;
}
/**
* 吃水果
*
*
@param
str
*
@return
*/
public
static
Fruit eatFruit(String str)
{
str
=
str.toLowerCase();
if
(str.equals(
"
apple
"
))
return
new
Apple();
if
(str.equals(
"
grape
"
))
return
new
Grape();
if
(str.equals(
"
pear
"
))
return
new
Pear();
return
null
;
}
}
6、 编写测试类:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.simplefactory;
public
class
Client
{
public
static
void
main(String[] args)
{
Apple apple
=
(Apple) FruitFactory.plantFruit(
"
apple
"
);
apple.plant();
Apple appleEat
=
(Apple) FruitFactory.eatFruit(
"
apple
"
);
appleEat.enableEat();
Grape grape
=
(Grape) FruitFactory.plantFruit(
"
grape
"
);
grape.plant();
Grape grapeEat
=
(Grape) FruitFactory.eatFruit(
"
grape
"
);
grapeEat.enableEat();
Pear pear
=
(Pear) FruitFactory.plantFruit(
"
pear
"
);
pear.plant();
Pear pearEat
=
(Pear) FruitFactory.eatFruit(
"
pear
"
);
pearEat.enableEat();
}
}
7、 说明:
A:我要购买苹果,只需向工厂角色(BuyFruit)请求即可。而工厂角色在接到请求后,会自行判断创建和提供哪一个产品。
B:但是对于工厂角色(FruitFactory)来说,增加新的产品(比如说增加草莓)就是一个痛苦的过程。工厂角色必须知道每一种产品,如何创建它们,以及何时向客户端提供它们。换言之,接纳新的产品意味着修改这个工厂。
C:因此Simple Factory模式的开放性比较差。
有什么办法可以解决这个问题吗?那就需要Factory Method模式来为我们服务了。
二、Factory Method模式:
1、同样,我们先定义水果(Fruit)接口:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
public
interface
Fruit
{
void
plant();
}
2、苹果(Apple)是对水果(Fruit)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
public
class
Apple
implements
Fruit
{
public
void
plant()
{
System.out.println(
"
plant apple
"
);
}
}
3、葡萄(Grape)是对水果(Fruit)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
public
class
Grape
implements
Fruit
{
public
void
plant()
{
System.out.println(
"
plant grape
"
);
}
}
4、鸭梨(Pear)是对水果(Fruit)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
public
class
Pear
implements
Fruit
{
public
void
plant()
{
System.out.println(
"
plant pear
"
);
}
}
5、在这里我们将买水果(FruitFactory)定义为接口类:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
public
interface
FruitFactory
{
Fruit plantFruit();
}
6、种植苹果是(PlantApple)对水果工厂(FruitFactory)这个接口的实现
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
import
com.pattern.factorymethod.FruitFactory;
public
class
PlantApple
implements
FruitFactory
{
public
Fruit plantFruit()
{
return
new
Apple();
}
}
7、种植鸭梨是(PlantBear)对水果工厂(FruitFactory)这个接口的实现
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
public
class
PlantPear
implements
FruitFactory
{
public
Fruit plantFruit()
{
return
new
Pear();
}
}
8、种植葡萄是(PlantGrape)对水果工厂(FruitFactory)这个接口的实现
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
public
class
PlantGrape
implements
FruitFactory
{
public
Fruit plantFruit()
{
return
new
Grape();
}
}
9、编写测试类:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.factorymethod;
/**
* 测试类
*
@author
supercrsky
*
*/
public
class
Client
{
public
static
void
main(String[] args)
{
FruitFactory factory
=
new
PlantApple();
factory.plantFruit().plant();
factory
=
new
PlantGrape();
factory.plantFruit().plant();
factory
=
new
PlantPear();
factory.plantFruit().plant();
}
}
10、说明:
A:工厂方法模式和简单工厂模式在结构上的不同是很明显的。工厂方法模式的核心是一个抽象工厂类,而简单工厂模式把核心放在一个具体类上。工厂方法模式可以允许很多具体工厂类从抽象工厂类中将创建行为继承下来,从而可以成为多个简单工厂模式的综合,进而推广了简单工厂模式。
B:工厂方法模式退化后可以变得很像简单工厂模式。设想如果非常确定一个系统只需要一个具体工厂类,那么就不妨把抽象工厂类合并到具体的工厂类中去。由于反正只有一个具体工厂类,所以不妨将工厂方法改成为静态方法,这时候就得到了简单工厂模式。
C:如果需要加入一个新的水果,那么只需要加入一个新的水果类以及它所对应的工厂类。没有必要修改客户端,也没有必要修改抽象工厂角色或者其他已有的具体工厂角色。对于增加新的水果类而言,这个系统完全支持“开-闭”原则。
D:对Factory Method模式而言,它只是针对一种类别(如本例中的水果类Fruit),但如果我们还想买肉,那就不行了,这是就必须要Abstract Factory Method模式帮忙了。
三、Abstract Factory模式
1、同样,我们先定义水果(Fruit)接口:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.abstractfactory;
public
interface
Fruit
{
void
plant();
}
2、苹果(Apple)是对水果(Fruit)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.abstractfactory;
public
class
Apple
implements
Fruit
{
public
void
plant()
{
System.out.println(
"
种植苹果
"
);
}
}
2、 定义肉(Meat)接口:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.abstractfactory;
public
interface
Meat
{
void
feed();
}
3、 猪肉(PigMeat)是对肉(Meat)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.abstractfactory;
public
class
PigMeat
implements
Meat
{
public
void
feed()
{
System.out.println(
"
猪肉
"
);
}
}
4、 牛肉(CowMeat)是对肉(Meat)接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.abstractfactory;
public
class
CowMeat
implements
Meat
{
public
void
feed()
{
System.out.println(
"
牛肉
"
);
}
}
5、 我们可以定义工厂接口:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.abstractfactory;
public
interface
Factory
{
//
种水果
Fruit plantFruit(Fruit fruit);
//
养肉
Meat feedMeat(Meat meat);
}
6、 我(MyFactory)是对Factory接口的实现:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.abstractfactory;
public
class
MyFactory
implements
Factory
{
//
养肉的工厂方法
public
Meat feedMeat(Meat meat)
{
return
meat;
}
//
种水果的工厂方法
public
Fruit plantFruit(Fruit fruit)
{
return
fruit;
}
}
7、编写测试类:
<!--<br /> <br /> Code highlighting produced by Actipro CodeHighlighter (freeware)<br /> http://www.CodeHighlighter.com/<br /> <br /> -->
package
com.pattern.abstractfactory;
public
class
Client
{
public
static
void
main(String[] args)
{
Fruit apple
=
new
Apple();
Meat pigMeat
=
new
PigMeat();
Factory factory
=
new
MyFactory();
//
种植苹果
factory.plantFruit(apple);
//
养殖猪肉
factory.feedMeat(pigMeat);
}
}
8、说明:
A:抽象工厂模式可以向客户端提供一个接口,使得客户端在不必指定产品的具体类型的情况下,创建多个产品族中的产品对象。这就是抽象工厂模式的用意。
B:抽象工厂模式是所有形态的工厂模式中最为抽象和最具一般性的一种形态。