multithreading - Java concurrency - is monitor blocked? -

is there way tell 1 thread (say 1 locks monitor object) if thread blocked / waiting on same monitor?

example scenario -

a "collector" thread reads data shared object, while "updater" thread might blocked , waiting collection end. collector know when finishes collecting, possible data update pending yield collected data might invalid.

in case collecting might time consuming operation, , in next stage "collector" thread analyzes data more time, might redundant operation in many cases data invalid.

is there way tell 1 thread (say 1 locks monitor object) if thread block/waiting on same monitor?

no, not object itself. can, @evgeniy mentioned, use other of java.util.concurrent.locks.* classes allow view queued members, not synchronized (lock) type of object monitor.

i collector know when finishes collecting, possible data update pending yield collected data might invalid.

how having blockingqueue of updates collector check queue , see if non-empty. updater thread(s) adding update information blockingqueue , collector dequeue updates , make adjustments. check length of queue , make decision whether or not needed move analysis mode.

private blockingqueue<update> updatequeue = new linkedblockingqueue<update>(); ... // called updater thread(s) public void updatedata(update update) {     updatequeue.put(update); } // called collector public void collect() {     while (!thread.currentthread().isinterrupted()) {         update update = updatequeue.take();         updatevalues(update);         if (updatequeue.isempty()) {            analyzedata();         }     } } 

regardless of how it, going need account new data update using other mechanism opposed checking threads' blocked state.