public VoidAggregation unpin(long originatorId, long taskId) {
        RequestDescriptor descriptor = RequestDescriptor.createDescriptor(originatorId, taskId);
        VoidAggregation aggregation;
        if ((aggregation = clipboard.get(descriptor)) != null) {
            clipboard.remove(descriptor);
            trackingCounter.decrementAndGet();

            // FIXME: we don't want this here
            //            completedQueue.clear();

            return aggregation;
        } else
            return null;
    }
public VoidAggregation unpin ( long originatorId , long taskId ) { RequestDescriptor descriptor = RequestDescriptor . createDescriptor ( originatorId , taskId ) ; VoidAggregation aggregation ; if ( ( aggregation = clipboard . get ( descriptor ) ) != null ) { clipboard . remove ( descriptor ) ; trackingCounter . decrementAndGet ( ) ; return aggregation ; } else return null ; }
This method removes given VoidAggregation from clipboard, and returns it

@param taskId