private void addProcessing(Processing processing) {
        if ( ! isAcceptingNewProcessings())
            throw new IllegalStateException("Docproc service " + getName() + 
                                            " is not accepting new incoming processings. Cannot add " + processing + " ");

        if ( ! queue.offer(processing))
            throw new RejectedExecutionException("Docproc service " + getName() + " is busy, please try later");
    }
Asynchronously process the given document operations as one unit
using the processing chain of this service.

@throws RuntimeException caused by a QueueFullException if this DocprocService has a bounded input queue and the queue is full
@throws IllegalStateException if this DocprocService is not accepting new incoming processings
docproc/src/main/java/com/yahoo/docproc/impl/DocprocService.java