android - Don't know how use wait() and notify() in Java -

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• how use wait , notify in java? 12 answers

i want make inside thread return did string, , i'd wait string other thins. i've been reading wait() , notify() dint it. can me?

here create thread operations

new thread(  new runnable() {      @override     public void run() {          synchronized(mensaje) {              try {                 mensaje.wait();                 mensaje = getfilesfromurl(value);             } catch (interruptedexception e) {                 e.printstacktrace();             }          }     }  }).start(); 

and here wait string mensaje changes

if string not "" show button , text

synchronized(mensaje) {      if (mensaje.equals("")) {          try {             mensaje.wait();         } catch (interruptedexception e) {             e.printstacktrace();         }      }      btnok.setvisibility(view.visible);     lblestado.settext(mensaje); } 

all stuff inside method

notify(), notifyall() , wait() work this:

when call wait() releases mutex taken synchronized block , puts current thread sleep in queue.

notify() grabs 1 waiting thread front of queue. thread reacquires mutex , continues running.

notifyall() wakes threads in queue.

to use here pseudocode (lacks exception handling etc bit more clear):

// in thread supposed wait synchronized {     while(!somecondition) {         wait();     }     // @ point other thread has made condition true , notified you. }   // in other thread synchronized {     // changes somecondition true.     notifyall(); } 

edit: or thilo wrote @ java.util.concurrent first. there might ready-made solution use case. no need use low-level constructs then.

correction: there ready-made solution use-case: http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/future.html

and corresponding executor.