Java-wait ()/notify ()

1. Wait () Usage: Wait () is wrapped in a while statement because some other task may suddenly get in and take the order when Waitperson is awakened;

2. Wait (), notify () and Notifyall () can only be called in the synchronous control method or in the synchronization control block;

Importjava.util.concurrent.*; Public classMeal {Private Final intOrdernum;  PublicMeal (intordernum) {             This. ordernum=Ordernum; }         PublicString toString () {return"Meal" +Ordernum; }} Public classRestaurant {Meal Meal; Executorservice exec=Executors.newcachedthreadpool (); Waitperson Waitperson=NewWaitperson ( This); Chef Chef=NewChef ( This);  PublicRestaurant () {exec.execute (Waitperson);    Exec.execute (chef); }} Public classWaitpersonImplementsrunnable{PrivateRestaurant Restaurant;  PublicWaitperson (Restaurant r) {Restaurant=R; } @Override Public voidrun () {Try{             while(!thread.interrupted ()) {                synchronized( This) {                     while(restaurant.meal==NULL) {wait ();//For the chef to produce a meal}} System.out.println ("Waitperson got" +restaurant.meal); synchronized(restaurant.chef) {restaurant.meal=NULL;                 Restaurant.chef.notifyAll (); }            }        }Catch(interruptedexception e) {System.out.println ("Waitperson interrupted"); }        }} Public classChefImplementsRunnable {PrivateRestaurant Restaurant; Private intCount=0;  PublicChef (Restaurant r) {Restaurant=R; } @Override Public voidrun () {Try{             while(!thread.interrupted ()) {                synchronized( This){                     while(restaurant.meal!=NULL) {wait (); }                }                                if(++count==10) {System.out.println ("Out of Food.closing");                Restaurant.exec.shutdownNow (); } System.out.print ("Order up!"); synchronized(Restaurant.waitperson) {restaurant.meal=NewMeal (count);                Restaurant.waitPerson.notifyAll (); }                                //TimeUnit.MILLISECONDS.sleep (+);            }        }Catch(interruptedexception e) {System.out.println ("Chef interrupted"); }    }}

Java-wait ()/notify ()