MessageFilter.onMatched

// line 405 of https://github.com/freenet/fred/blob/3fcc2d1b3a0d5ccbeb73928d6b267440e5b4c17b/src/freenet/io/comm/MessageFilter.java
/**
     * Notify waiters that we have been matched.
     * Hopefully no locks will be held at this point by the caller.
     */
    public void onMatched(Executor executor) {
        final Message msg;
        final AsyncMessageFilterCallback cb;
        ByteCounter ctr;
        synchronized(this) {
            msg = _message;
            cb = _callback;
            ctr = _ctr;
            // Clear matched before calling callback in case we are re-added.
            if(_callback != null)
                clearMatched();
        }
        if(cb != null) {
            if(cb instanceof SlowAsyncMessageFilterCallback)
                executor.execute(new PrioRunnable() {

                    @Override
                    public void run() {
                        cb.onMatched(msg);
                    }

                    @Override
                    public int getPriority() {
                        return ((SlowAsyncMessageFilterCallback)cb).getPriority();
                    }

                }, "Slow callback for "+cb);
            else
                cb.onMatched(msg);
            if(ctr != null)
                ctr.receivedBytes(msg._receivedByteCount);
        }
    }