行为型之二-命令模式

Command（命令模式）

将一个请求封装为一个对象，从而使你可用不同的请求对客户进行参数化；对请求排队或记录请求日志，以及支持可撤销的操作。

VC.m

//waiter用于接收各种类型的order。waiter是请求接收者。
//接收不同customer产生的不同order，并且都存入waiter这个接受者中,type表示不同类型的order。
HCDWaiter *waiter = [[HCDWaiter alloc]init];
//顾客一
HCDCustomr *customer = [[HCDCustomr alloc]init];
HCDOrder *customerOrder1 = [customer pushOrderWithString:@"顾客一要十串羊肉" type:orderTypeMutton];
 HCDOrder *customerOrder2 = [customer pushOrderWithString:@"顾客一要十串鸭肉" type:orderTypeDuck];
[waiter addOrder:customerOrder1];
[waiter addOrder:customerOrder2];
//顾客二
HCDCustomr *customer1 = [[HCDCustomr alloc]init];
HCDOrder *customer1Order1 = [customer1 pushOrderWithString:@"顾客二要二十串鸡肉" type:orderTypeChicken];
HCDOrder *customer1Order2 = [customer1 pushOrderWithString:@"顾客二要二十串鸭肉" type:orderTypeDuck];
[waiter addOrder:customer1Order1];
[waiter addOrder:customer1Order2];
//顾客取消Order
[waiter deleteOrder:customer1Order2];
//waiter发送order，背后有一个HCDWorker这个单列作为行为实现者来处理具体的order。命令接收完毕，开始发送命令。
[waiter notifyOrder];

HCDWaiter.h

@interface HCDWaiter : NSObject
-(void)addOrder:(HCDOrder *)order;
-(void)deleteOrder:(HCDOrder *)order;
-(void)notifyOrder;
@end

HCDWaiter.m

@interface HCDWaiter ()
//用于存储命令列表
@property(nonatomic,strong)NSMutableArray *orderList;
@end
@implementation HCDWaiter
-(instancetype)init{
    self = [super init];
    if (self) {
        _orderList = [NSMutableArray array];
    }
    return self;
}
-(void)addOrder:(HCDOrder *)order{
    NSLog(@"添加Order");
    [self.orderList addObject:order];
}
-(void)deleteOrder:(HCDOrder *)order{
    NSLog(@"取消Order");
    [self.orderList removeObject:order];
}
/*
 命令接收完毕，开始执行命令
 */
-(void)notifyOrder{
    NSLog(@"====开始执行Order===");
    for (HCDOrder *order in self.orderList) {
        [order executeOrder];
    }
}
@end

设计图