iOS设计模式 (十)中介者模式

概念

• 中介者模式，定义了一个中介对象来封装一系列对象之间的交互关系。中介者使各个对象之间不需要显式地相互引用，从而使耦合性降低，而且可以独立地改变它们之间的交互行为。通俗的讲就是如果你想租房，一般不会去找房东，房东会把房源租金注意事项交给中介，然后你直接找中介就可以租房了。

  
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中介者UML

中介者.png

demo实例

• AbstractColleage

#import <Foundation/Foundation.h>

@class AbstractColleage;

@protocol colleageDelegate<NSObject>

- (void)colleageValue:(AbstractColleage *)event;

@end

@interface AbstractColleage : NSObject

@property (nonatomic, weak) id <colleageDelegate>delegate;

@end

#import "AbstractColleage.h"

@implementation AbstractColleage

@end

• Colleage 类

#import "AbstractColleage.h"

@interface Colleage : AbstractColleage

- (void)changeValue:(float)value;

@property (nonatomic, assign)float value;

@end

#import "Colleage.h"

@implementation Colleage

- (void)changeValue:(float)value{
    self.value = value;
    if (self.delegate && [self.delegate respondsToSelector:@selector(colleageValue:)]) {
        [self.delegate colleageValue:self];
    }
}

@end

• AbstractMediator

#import <Foundation/Foundation.h>
#import "AbstractColleage.h"

@interface AbstractMediator : NSObject <colleageDelegate>

@end
#import "AbstractMediator.h"


@implementation AbstractMediator

- (void)colleageValue:(AbstractColleage *)event
{
    
}

@end

• MediatorOne

#import "AbstractMediator.h"
#import "Colleage.h"

@interface MediatorOne : AbstractMediator

@property (nonatomic, strong)Colleage *colleageA;
@property (nonatomic, strong)Colleage *colleageB;
@property (nonatomic, strong)Colleage *colleageC;


- (NSDictionary *)values;

@end
#import "MediatorOne.h"

@implementation MediatorOne

- (NSDictionary *)values
{
    return  @{
              @"A":@(self.colleageA.value),
              @"B":@(self.colleageB.value),
              @"C":@(self.colleageC.value),
              };
    
}

- (void)colleageValue:(AbstractColleage *)event
{
    if ([event isEqual:self.colleageA]) {
    
        self.colleageB.value = self.colleageA.value *4;
        self.colleageC.value = self.colleageA.value *6;
    }
    else if ([event isEqual:self.colleageB]){
        self.colleageA.value = self.colleageA.value *2;
        self.colleageB.value = self.colleageB.value /2;
        self.colleageC.value = self.colleageC.value /5;
    }
    else {
        self.colleageA.value = self.colleageA.value *2;
        self.colleageB.value = self.colleageB.value *3;
        self.colleageC.value = self.colleageC.value *4;
    }
}

@end

demo地址：https://github.com/defuliu/MediatorPattern