Objective-C实现生产者消费者问题

     
    
      
实现思路
    
      
为了确保生产者不会在缓冲区满时继续生产，消费者在缓冲区空时不会继续消费，我们需要使用同步机制。在Objective-C中，NSCondition是一个强大的工具，可以帮助我们实现这一点。
  
     
  
     
    
      
     

#import <Foundation/Foundation.h>

#define BUFFER_SIZE 5

@interface ProducerConsumerViewController : NSViewController

@implementation ProducerConsumerViewController

• (void)viewDidLoad)

  {
  [super viewDidLoad];
  self.buffer = [NSMutableArray new];
  self.queue = [NSOperationQueue new];
  self.condition = [NSCondition new];
  }

• (void *)producerThread:(NSThread *)thread

  {
  while (true) {
  [self.condition wait];
  if ([self.buffer count] < BUFFER_SIZE) {
  [self.buffer addObject:[NSDate new]];
  } else {
  // 缓冲区已满，生产者暂停
  sleep(1);
  }
  }
  }

• (void *)consumerThread:(NSThread *)thread

  {
  while (true) {
  [self.condition wait];
  if ([self.buffer count] > 0) {
  [self.buffer removeObjectAtIndex:0];
  } else {
  // 缓冲区为空，消费者暂停
  sleep(1);
  }
  }
  }

• (void)startThreads

  {
  [self.queue addExecutionThreadWithName:@"生产者" target:self selector:@selector(producerThread:)];
  [self.queue addExecutionThreadWithName:@"消费者" target:self selector:@selector(consumerThread:)];
  }

• (void)stopThreads

  {
  [self.queue cancelAllOperations];
  }