reliableinputstream.java

JXTA&#8482 is a set of open, generalized peer-to-peer (P2P) protocols that allow any networked devi

                LOG.log(Level.WARNING, "sendACK caught IOException:", e);
            }
        }
    }
    
    /**
     *  {@inheritDoc}
     */
    public void recv(Message msg) {
        queueIncomingMessage(msg);
    }
    
    public boolean hasNextMessage() {
        return !inputQueue.isEmpty();
    }
       
    Message nextMessage(boolean blocking) throws IOException {
        if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
            LOG.fine("nextMessage blocking?  [" + blocking + "]");
        }
        MessageElement elt = dequeueMessage(sequenceNumber + 1, blocking);

        if (null == elt) {
            return null;
        }
        sequenceNumber += 1; // next msg sequence number
        
        Message msg;

        try {
            if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                LOG.fine("Converting message seqn :" + (sequenceNumber - 1) + "element to message");
            }
            
            msg = WireFormatMessageFactory.fromWire(elt.getStream(), Defs.MIME_TYPE_MSG, null);
        } catch (IOException ex) {
            if (Logging.SHOW_WARNING && LOG.isLoggable(Level.WARNING)) {
                LOG.log(Level.WARNING, "Could not deserialize message " + elt.getElementName(), ex);
            }
            return null;
        }
        return msg;
    }
    
    /**
     *  queue messages by sequence number.
     */
    private void queueIncomingMessage(Message msg) {
        
        if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
            LOG.fine("Queue Incoming Message begins for " + msg);
        }
        
        long startEnqueue = TimeUtils.timeNow();
        
        Iterator<MessageElement> eachElement = msg.getMessageElements(Defs.NAMESPACE, Defs.MIME_TYPE_BLOCK);
        
        // OK look for jxta message
        while (!closed && !closing && eachElement.hasNext()) {
            MessageElement elt = eachElement.next();

            eachElement.remove();
            
            int msgSeqn;

            try {
                msgSeqn = Integer.parseInt(elt.getElementName());
            } catch (NumberFormatException n) {
                if (Logging.SHOW_WARNING && LOG.isLoggable(Level.WARNING)) {
                    LOG.warning("Discarding element (" + elt.getElementName() + ") Not one of ours.");
                }
                continue;
            }
            
            IQElt newElt = new IQElt(msgSeqn, elt);
            
            // OK we must enqueue
            
            // We rely on the sender to not to send more than the window size
            // because we do not limit the number of elements we allow to be
            // enqueued.
            
            // see if this is a duplicate
            if (newElt.seqnum <= sequenceNumber) {
                if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                    LOG.fine("RCVD OLD MESSAGE : Discard seqn#" + newElt.seqnum + " now at seqn#" + sequenceNumber);
                }
                break;
            }
            
            synchronized (inputQueue) {
                
                // dbl check with the lock held.
                if (closing || closed) {
                    return;
                }
                
                // Insert this message into the input queue.
                // 1. Do not add duplicate messages
                // 2. Store in increasing sequence nos.
                int insertIndex = inputQueue.size();
                boolean duplicate = false;
                
                for (int j = 0; j < inputQueue.size(); j++) {
                    IQElt iq = inputQueue.get(j);

                    if (newElt.seqnum < iq.seqnum) {
                        insertIndex = j;
                        break;
                    } else if (newElt.seqnum == iq.seqnum) {
                        duplicate = true;
                        break;
                    }
                }
                
                if (duplicate) {
                    if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                        LOG.fine("RCVD OLD MESSAGE :  Discard duplicate msg, seqn#" + newElt.seqnum);
                    }
                    break;
                }
                
                inputQueue.add(insertIndex, newElt);
                
                if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                    LOG.fine("Enqueued msg with seqn#" + newElt.seqnum + " at index " + insertIndex);
                }
                
                inputQueue.notifyAll();
            }
        }
        
        if (listener != null) {
            Message newmsg = null;

            while (true) {
                try {
                    newmsg = nextMessage(false);
                } catch (IOException io) {// do nothing as this exception will never occur
                }
                if (newmsg == null) {
                    break;
                }
                try {
                    if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                        LOG.fine("In listener mode, calling back listener");
                    }
                    listener.processIncomingMessage(newmsg);
                } catch (Throwable all) {
                    if (Logging.SHOW_WARNING && LOG.isLoggable(Level.WARNING)) {
                        LOG.log(Level.WARNING, "Uncaught Throwable calling listener", all);
                    }
                }
            }
        }
        
        if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
            long waited = TimeUtils.toRelativeTimeMillis(TimeUtils.timeNow(), startEnqueue);

            LOG.fine("Queue Incoming Message for " + msg + " completed in " + waited + " msec.");
        }
    }
    
    long nextRetransRequest = TimeUtils.toAbsoluteTimeMillis(TimeUtils.ASECOND);
    
    /**
     *  Dequeue the message with the desired sequence number waiting as needed
     *  until the message is available.
     *
     *  @param desiredSeqn the sequence number to be dequeued.
     *  @param blocking If {@code true} then this method should block while
     *  waiting for the specified message sequence number.
     *  @return the Message Element with the desired sequence number or null if
     *  the queue has been closed.
     */
    private MessageElement dequeueMessage(int desiredSeqn, boolean blocking) throws IOException {
        IQElt iQ = null;
        
        // Wait for incoming message here
        long startDequeue = TimeUtils.timeNow();
        long timeoutAt = TimeUtils.toAbsoluteTimeMillis(timeout);
        int wct = 0;
        
        synchronized (inputQueue) {
            while (!closed) {
                if (inputQueue.isEmpty()) {
                    if (!blocking) {
                        return null;
                    }
                    if (closing) {
                        return null;
                    }
                    try {
                        wct++;
                        inputQueue.wait(TimeUtils.ASECOND);
                        if (timeoutAt < TimeUtils.timeNow()) {
                            throw new SocketTimeoutException("Read timeout reached");
                        }
                    } catch (InterruptedException e) {
                        Thread.interrupted();
                    }
                    // reset retrans request timer since we don't want to immediately
                    // request retry after a long wait for out of order messages.
                    
                    nextRetransRequest = TimeUtils.toAbsoluteTimeMillis(TimeUtils.ASECOND);
                    continue;
                }
                
                iQ = inputQueue.get(0); // FIFO
                
                if (iQ.seqnum < desiredSeqn) {
                    // Ooops a DUPE slipped in the head of the queue undetected
                    // (seqnum consistency issue).
                    // Just drop it.
                    inputQueue.remove(0);
                    // if such is the case then notify the other end so that
                    // the message does not remain in the retry queue eventually
                    // triggering a broken pipe exception
                    sendACK(iQ.seqnum);
                    continue;
                } else if (iQ.seqnum != desiredSeqn) {
                    if (TimeUtils.toRelativeTimeMillis(nextRetransRequest) < 0) {
                        if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                            LOG.fine("Trigger retransmission. Wanted seqn#" + desiredSeqn + " found seqn#" + iQ.seqnum);
                        }
                        sendACK(desiredSeqn - 1);
                        nextRetransRequest = TimeUtils.toAbsoluteTimeMillis(TimeUtils.ASECOND);
                    }
                    if (!blocking) {
                        if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                            LOG.fine("Message out of sequece in Non-Blocking mode. returning");
                        }
                        // not the element of interest return nothing
                        return null;
                    }
                    try {
                        wct++;
                        inputQueue.wait(TimeUtils.ASECOND);
                        if (timeoutAt < TimeUtils.timeNow()) {
                            throw new SocketTimeoutException("Read timeout reached");
                        }
                    } catch (InterruptedException e) {
                        throw new InterruptedIOException("IO interrupted ");
                    }
                    continue;
                }
                inputQueue.remove(0);
                break;
            }
        }
        nextRetransRequest = 0;
        // if we are closed then we return null
        if (null == iQ) {
            return null;
        }
        
        sendACK(desiredSeqn);
        
        if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
            long waited = TimeUtils.toRelativeTimeMillis(TimeUtils.timeNow(), startDequeue);

            LOG.fine("DEQUEUED seqn#" + iQ.seqnum + " in " + waited + " msec on input queue");
            if (wct > 0) {
                LOG.fine("DEQUEUE waited " + wct + " times on input queue");
            }
        }
        return iQ.elt;
    }
    
    /**
     * {@inheritDoc}
     */
    @Override
    public int available() throws IOException {
        if (listener != null) {
            throw new IOException("available() not supported in async mode");
        }
        if (closed) {
            throw new IOException("Stream closed");
        }
        synchronized (record) {
            if (record.inputStream != null) {
                if ((record.size == 0) || (record.nextByte == record.size)) {
                    if (inputQueue.isEmpty()) {
                        return 0;
                    }
                    // reset the record
                    record.resetRecord(); // GC as necessary(inputStream byte[])
                    if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                        LOG.fine("Getting next data block at seqn#" + (sequenceNumber + 1));
                    }
                    MessageElement elt = dequeueMessage(sequenceNumber + 1, false);

                    if (null == elt) {
                        return 0;
                    }
                    sequenceNumber += 1; // next msg sequence number
                    // Get the length of the Record
                    record.size = elt.getByteLength();
                    record.inputStream = elt.getStream();
                }
                return record.inputStream.available();
            }
        }
        return 0;
    }
    
    private int local_read(byte[] buf, int offset, int length) throws IOException {
        
        if (listener != null) {
            throw new IOException("read() not supported in async mode");
        }
        
        synchronized (record) {
            if ((record.size == 0) || (record.nextByte == record.size)) {
                
                // reset the record
                record.resetRecord(); // GC as necessary(inputStream byte[])
                
                if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                    LOG.fine("Getting next data block at seqn#" + (sequenceNumber + 1));
                }
                
                MessageElement elt = dequeueMessage(sequenceNumber + 1, true);
                
                if (null == elt) {
                    return -1;
                }
                
                sequenceNumber += 1; // next msg sequence number
                
                // Get the length of the Record
                record.size = elt.getByteLength();
                record.inputStream = elt.getStream();
                
                if (Logging.SHOW_FINE && LOG.isLoggable(Level.FINE)) {
                    LOG.fine("new seqn#" + sequenceNumber + ", bytes = " + record.size);
                }
            }
            
            // return the requested Record data
            // These calls should NEVER ask for more data than is in the
            // received Record.
            
            long left = record.size - record.nextByte;
            int copyLen = (int) Math.min(length, left);
            int copied = 0;
            
            do {
                int res = record.inputStream.read(buf, offset + copied, copyLen - copied);
                
                if (res < 0) {
                    break;
                }
                copied += res;
            } while (copied < copyLen);
            
            record.nextByte += copied;
            
            if (Logging.SHOW_FINER && LOG.isLoggable(Level.FINER)) {
                LOG.finer("Requested " + length + ", Read " + copied + " bytes");
            }
            
            return copied;
        }
    }
    
    /**
     * Returns the message listener for this pipe
     * @return MsgListener
     *
     */
    public MsgListener getListener() {
        return listener;
    }
    
    /**
     *  The listener interface for receiving {@link net.jxta.endpoint.Message}
     */
    public interface MsgListener {
        
        /**
         * Called for each message received.
         *
         * @param message The message to be received.
         */
        void processIncomingMessage(Message message);
    }
}