设计方式系列6-工厂模式

设计模式系列6-工厂模式

设计模式系列6-工厂模式


前言:

前一节讲了建造者模式,这一节我们讲23种设计模式之工厂方法模式。

什么是工厂方法模式?

定义创建对象的接口,让子类决定实例化哪一个类,工厂方法使得一个类的实例化延迟到子类。(最初定义出于于《设计模式》(Addison-Wesley,1994))。

何时使用工厂方法模式?

在以下情境中,自然会想到使用这一模式:
1.编译时无法准确预期要创建的对象的类;
2.类想让其子类决定在运行时创建什么;
3.类有若干辅助类为其子类,而你想将返回哪个子类这一信息局部化。


工厂方法在iOS中的实现:

1.定义一个抽象手机类:
@interface FMCellPhone : NSObject

- (void)call;

@end

#import "FMCellPhone.h"

@implementation FMCellPhone

- (void)call

{

}

@end


2.定义一个具体手机类FMAppleCellPhone:
#import "FMCellPhone.h"

@interface FMAppleCellPhone : FMCellPhone

@end

#import "FMAppleCellPhone.h"

@implementation FMAppleCellPhone

- (void)call

{

    NSLog(@"apple手机打电话");

}

@end


3.创建一个具体手机类FMNOKIACellPhone:
#import "FMCellPhone.h"

@interface FMNOKIACellPhone : FMCellPhone

@end

#import "FMNOKIACellPhone.h"

@implementation FMNOKIACellPhone

- (void)call

{

    NSLog(@"NOKIA手机打电话");

}

@end


4.创建一个抽象工厂类FMCellPhoneFactory:
#import <Foundation/Foundation.h>
#import "FMCellPhone.h"

//这是一个抽象电话工厂类,提供造电话功能
@interface FMCellPhoneFactory : NSObject

- (FMCellPhone *)buildCellPhone;

@end

#import "FMCellPhoneFactory.h"

@implementation FMCellPhoneFactory

- (FMCellPhone *)buildCellPhone

{

    

}

@end


5.创建Apple手机具体工厂类:
#import "FMCellPhoneFactory.h"

@interface FMAppleCellPhoneFactory : FMCellPhoneFactory

@end

#import "FMAppleCellPhoneFactory.h"

#import "FMCellPhone.h"

#import "FMAppleCellPhone.h"

@implementation FMAppleCellPhoneFactory

- (FMCellPhone *)buildCellPhone

{

    NSLog(@"Apple手机工厂");

    return [[FMAppleCellPhone alloc] init];

}

@end


6.创建NOKIA手机具体工厂类:
#import "FMCellPhoneFactory.h"

@interface FMNOKIACellPhoneFactory : FMCellPhoneFactory

@end

#import "FMNOKIACellPhoneFactory.h"

#import "FMNOKIACellPhone.h"

#import "FMCellPhone.h"

@implementation FMNOKIACellPhoneFactory

- (FMCellPhone *)buildCellPhone

{

    NSLog(@"NOKIA手机工厂");

    return [[FMNOKIACellPhone alloc] init];

}

@end


7.测试:
//制造一个Apple电话,打电话
    FMCellPhoneFactory *appleFactory = [[FMAppleCellPhoneFactory alloc] init];
    FMCellPhone *applePhone = [appleFactory buildCellPhone];
    [applePhone call];
    
    //制造一个NOKIA电话,打电话
    FMCellPhoneFactory *NOKIAFactory = [[FMNOKIACellPhoneFactory alloc] init];
    FMCellPhone *NOKIAPhone = [NOKIAFactory buildCellPhone];
    [NOKIAPhone call];

8.测试结果如下图:
设计方式系列6-工厂模式



源码下载:http://download.****.net/detail/yanglei_java/6439373