iOS-有限缓冲问题经典案例-生产者消费者-NSThread多线程

  1 #import "ViewController.h"
  2
  3 @interface ViewController ()
  4 {
  5     NSMutableArray *_arr;
  6     NSCondition *_condition;
  7 }
  8 @end
  9
 10 @implementation ViewController
 11
 12 - (void)viewDidLoad {
 13     [super viewDidLoad];
 14
 15     _arr = [NSMutableArray array];
 16     _condition = [[NSCondition alloc] init];
 17
 18
 19
 20 //    [self addProduct];
 21
 22
 23 //    1:1   2:1
 24     //生产者
 25 //    [NSThread detachNewThreadSelector:@selector(addProduct) toTarget:self withObject:nil];
 26
 27     NSThread *thread1 = [[NSThread alloc] initWithTarget:self selector:@selector(addProduct) object:nil];
 28     [thread1 start];
 29     NSThread *thread3 = [[NSThread alloc] initWithTarget:self selector:@selector(addProduct) object:nil];
 30     [thread3 start];
 31
 32     //消费者
 33 //    [NSThread detachNewThreadSelector:@selector(minProduct) toTarget:self withObject:nil];
 34
 35     NSThread *thread2 = [[NSThread alloc] initWithTarget:self selector:@selector(minProduct) object:nil];
 36     [thread2 start];
 37
 38
 39
 40 }
 41
 42
 43 - (void)addProduct {
 44
 45     while (TRUE) {
 46
 47
 48         [_condition lock];
 49
 50         @try {  //把有可能出现异常的代码放到try{  ..... }
 51 //            Code that can potentially throw an exception
 52
 53 //            [_arr objectAtIndex:1];
 54
 55             while (_arr.count == 10) {
 56
 57                 NSLog(@"库房已满，等待消费");
 58
 59                 //生产者等待，库房有空余位置
 60                 [_condition wait];
 61             }
 62
 63             [NSThread sleepForTimeInterval:.2];
 64             NSObject *obj = [[NSObject alloc] init];
 65             [_arr addObject:obj];
 66
 67             NSLog(@"生产了一个产品，库房总数是%ld",_arr.count);
 68
 69
 70             //唤醒在此NSCondition对象上等待的单个线程 （通知消费者进行消费）
 71             [_condition signal];
 72
 73
 74
 75         }
 76         @catch (NSException *exception) {  //处理try内出现的异常
 77 //            Handle an exception thrown in the @try block
 78
 79             NSLog(@"出现异常 %@",exception);
 80
 81         }
 82         @finally {   //不管是否出现异常 @finally{ ... } 都会执行
 83 //            Code that gets executed whether or not an exception is thrown
 84
 85             NSLog(@"@finally");
 86
 87             [_condition unlock];
 88         }
 89
 90
 91
 92     }
 93
 94 }
 95
 96 - (void)minProduct {
 97
 98     while (TRUE) {
 99
100
101         [_condition lock];
102
103         @try {  //把有可能出现异常的代码放到try{  ..... }
104             //            Code that can potentially throw an exception
105
106             //            [_arr objectAtIndex:1];
107
108             while (_arr.count == 0) {
109
110                 NSLog(@"库房没有产品，等待");
111
112                 //生产者等待，库房有空余位置
113                 [_condition wait];
114             }
115
116
117 //            NSObject *obj = [[NSObject alloc] init];
118 //            [_arr addObject:obj];
119             [_arr removeLastObject];
120
121             NSLog(@"消费了一个产品，库房总数是%ld",_arr.count);
122
123
124             //唤醒在此NSCondition对象上等待的单个线程 （通知生产者进行生产）
125             [_condition signal];
126
127         }
128         @catch (NSException *exception) {  //处理try内出现的异常
129             //            Handle an exception thrown in the @try block
130
131             NSLog(@"出现异常 %@",exception);
132
133         }
134         @finally {   //不管是否出现异常 @finally{ ... } 都会执行
135             //            Code that gets executed whether or not an exception is thrown
136
137             NSLog(@"@finally");
138
139             [_condition unlock];
140         }
141
142
143
144     }
145
146 }