Interesting producer-consumer issues

Reprint Please specify source: http://blog.csdn.net/sunyujia/

Forum on the question raised by the Netizen, each production 3 can only consume 2, feel not very difficult to do so, in order to save trouble

Modified on the basis of the original http://blog.csdn.net/sunyujia/archive/2008/05/02/2362015.aspx.

The only difficulty is that the production of 3 threads is not the same thread. A thread that consumes 2 threads is not the same thread. That is, a thread can not be a continuous production of 3, a thread of continuous consumption of 2, if a thread continuous production, the program is not interesting. import java.util.arraylist; import java.util.list; import java.util.concurrent.executorservice; import java.util.concurrent.executors; /**  *  interesting producer consumer issues  *  3 per generation of 2  *  @author:  sunyujia  *  @blog:  http://blog.csdn.net/sunyujia/ *  @mail:  sunyujia@sunyujia@yahoo.cn  */Public class  executorservicetest {    private static int producecount =  0;     private static int consumeCount = 0;     private static object producelock = new object ();     private static object consumelock = new object ();     public static void main (String[] args)  {      &nbsP;  final list tasks = new arraylist ();         system.out.println ("myblog: http://blog.csdn.net/" + " sunyujia/");         final ExecutorService exec =  Executors.newcachedthreadpool ();         for  (int i = 0; i < 10;  i++)  {//10 a producer             exec.execute ( New runnable ()  {                 public void run ()  {                     while  (! Thread.interrupted ())  {                          try {                             synchronized  (Consumelock)  {                                 if  ( PRODUCECOUNT&NBSP;&GT;=&NBSP;3)                                       consumelock.wait ();                              }                              synchronized  (producelock)  {                                  if  (producecount < 3)  {                                      tasks.add (New  object ());//  production                                       system.out.println (Thread.CurrentThread (). GetName () + "Production tasks   remaining:"  +  Tasks.size ());                                      producecount++;                                      if   (producecount >= 3)  {                                          consumeCount = 2;//  Tips for spending only 2                                           system.out.println ("producer friendly tips now in stock"                                                   +  tasks.size ());                                           producelock.notifyall ();                                      }                                       Thread.yield ();                                  }                              }                               thread.sleep (;// ) Let the program perform slowly for observation                           } catch  (interruptedexception e)  {                              e.printstacktrace ();                         }                      }                  }              });         }         for  (int  i = 0; i < 20; i++) &NBSP;{//20 Consumer              exec.execute (new runnable ()  {                 public void run ()  {                      while  (! Thread.interrupted ())  {                        try {                              synchronized  (producelock)  {                                  if  (consumecount <= 0)                                       Producelock.wait ();                              }                               synchronized  (consumelock)  {                                  if  (consumecount > 0)  {                                      tasks.remove (0);//  consumption                                       system.out.println ( Thread.CurrentThread (). GetName () + "Processing tasks   remaining:"                                               + tasks.size ());                                       consumecount--;                                      if   (consumecount <= 0)  {                                          produceCount = 0;//  Requires 3 more   &nbs to be generatedp;                                      &NBSP;SYSTEM.OUT.PRINTLN ("Consumer friendly tips now in stock"                                                   +  tasks.size ());                                           consumelock.notifyall ();                                      }                                   }                              }                               thread.sleep (;// ) Let the program perform slowly for observation                          }  catch  (interruptedexception e)  {                              e.printstacktRace ();                          }                      }                  }             } );         }         exec.shutdown ();     }}

The

Execution results are as follows:
Pool-1-thread-1 production tasks left: 1
pool-1-thread-2 production tasks left: 2
Pool-1-thread-4 production tasks left: 3
Manufacturer friendly tips now in stock 3
pool-1-thread-11 Processing tasks remaining: 2
pool-1-thread-12 processing tasks left: 1
Consumer friendly tips now in stock 1
pool-1-thread-5 production tasks remaining: 2
Pool-1-thread-6 production Tasks Left: 3
Pool-1-thread-7 production tasks left: 4
Producer friendly Tips now in stock 4
pool-1-thread-14 processing tasks remaining: 3
Pool-1-thread-16 processing tasks Left: 2
Consumer friendly tips now in Stock 2
pool-1-thread-3 production tasks remaining: 3
Pool-1-thread-2 production tasks left: 4
Pool-1-thread-4 production Tasks Left: 5
Producer friendly Tips now in stock 5