#23 Second of Two waitToRemoves Fails

[Brad Johanson]

I need some explanations on the following behaviour of
WaitToRemove...

I create an object wich waits to remove an event.
When it receives it, it puts in the event heap a new event
and waits to remove it.

The problem is that sometimes the thread is blocked in
the second
waitToRemove function. When I trace (with the
EventHeapDebugger)
events in the heap, no event exists.
So, I suppose that the second event is remove before
being get, but,
I don't
know why and how.
Someone can help me? What should I do to have a
"coherent" behaviour?

Here the code and the output:
public void go(){
try{
EventHeap iROS_eh = new
EventHeap(System.getProperty("heapMachine"));
Event[] tev;
Event[] res;
Event evSR;
tev = new Event[2];
tev[0] = new Event("foo1");
tev[1] = new Event("foo2");

  System.out.println("Waiting...");
  res = iROS_eh.waitToRemoveEvent(tev);

        Event ev = res[0];
        String evType = ev.getEventType();
        System.out.println("received :" + evType);

        if(evType.equals("foo1")){
              iROS_eh.putEvent(new Event("foo2"));
              System.out.println("Sent");
        }

  System.out.println("Waiting for the second time...");
  res = iROS_eh.waitToRemoveEvent(tev);
  System.out.println("OK! CORRECT");

}
catch(Exception e){
System.err.println("Exception : "+e.getMessage());
}
}

public static void main(String[] theArguments) {
Serveur s = new Serveur();
s.go();
} // main(String[])

A client send the event "foo1". The output is:
Connection: connected to machine:4535
Waiting...
received :foo1
Sent
Waiting for the second time...

This process is often blocked in the second WaitToRemove.

[Tomoto Shimizu Washio]

Logged In: YES
user_id=629201

Hi Brad, I have a possible explanation. This might be caused
by the bug #725885 I submitted before.

The server remains still waiting to remove a matching event
even if the waitToRemoveEvent call has been terminated in
the client side by CTRL+C or timeout. In this state, the first
matching event can be removed right away and returned to
nowhere.

It is likely that you pressed CTRL+C during
waitToRemoveEvent call before you experience this problem
for some reason. (There seems a path that waits to remove
foo2 without posting one and this might be the reason.) Once
you did, this problem happens over and over since you need
to CTRL+C every time the program is blocked in
waitToRemoveEvent.

Does it help? If this was your problem as I assume, you might
want to have further discussions in bug #725885.

[Nobody/Anonymous]

Logged In: NO

like what man