protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out)
throws Exception {
DecoderState decoderState = (DecoderState) session.getAttribute(DECODER_STATE_KEY);
if (decoderState == null) {
decoderState = new DecoderState();
session.setAttribute(DECODER_STATE_KEY, decoderState);
}
if (decoderState.image1 == null) {
// try to read first image
if (in.prefixedDataAvailable(4, MAX_IMAGE_SIZE)) {
decoderState.image1 = readImage(in);
} else {
// not enough data available to read first image
return false;
}
}
if (decoderState.image1 != null) {
// try to read second image
if (in.prefixedDataAvailable(4, MAX_IMAGE_SIZE)) {
BufferedImage image2 = readImage(in);
ImageResponse imageResponse = new ImageResponse(decoderState.image1, image2);
out.write(imageResponse);
decoderState.image1 = null;
return true;
} else {
// not enough data available to read second image
return false;
}
}
return false;
}
private void initializeStateQueues(
List<MinPriorityDecoderQueue<DecoderState>> decoderStateQueues, int sentenceLength) {
DecoderState startState = getStartState(sentenceLength);
for (int i = 0; i <= sentenceLength; ++i) {
MinPriorityDecoderQueue<DecoderState> queue =
new MinPriorityDecoderQueue<DecoderState>(BeamSizeForStatesQueue);
decoderStateQueues.add(queue);
}
decoderStateQueues.get(0).insert(startState, startState.getScore());
}
@Override
protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) {
// Get the state of the current message and
// Skip what we have already scanned
DecoderState state = decoderState(session);
in.position(state.current());
while (in.hasRemaining()) {
byte current = in.get();
// If it is the start byte and mark the position
if (current == config.getStartByte()) {
state.markStart(in.position() - 1);
}
// If it is the end bytes, extract the payload and return
if (state.previous() == config.getEndByte1() && current == config.getEndByte2()) {
// Remember the current position and limit.
int position = in.position();
int limit = in.limit();
LOG.debug("Message ends at position {} with length {}", position, position - state.start());
try {
in.position(state.start());
in.limit(position);
// The bytes between in.position() and in.limit()
// now contain a full MLLP message including the
// start and end bytes.
out.write(
config.isProduceString()
? parseMessageToString(in.slice(), charsetDecoder(session))
: parseMessageToByteArray(in.slice()));
} catch (CharacterCodingException cce) {
throw new IllegalArgumentException("Exception while finalizing the message", cce);
} finally {
// Reset position, limit, and state
in.limit(limit);
in.position(position);
state.reset();
}
return true;
}
// Remember previous byte in state object because the buffer could
// be theoretically exhausted right between the two end bytes
state.markPrevious(current);
}
// Could not find a complete message in the buffer.
// Reset to the initial position and return false so that this method
// is called again with more data.
LOG.debug("No complete message yet at position {} ", in.position());
state.markCurrent(in.position());
in.position(0);
return false;
}
private void UpdateStateQueue(
MinPriorityDecoderQueue<DecoderState> minPriorityDecoderQueue,
DecoderState curState,
DecoderState prevState,
ScoredPhrasePairForSentence phrase,
HashMap<DecoderState, BackPointerElement> backPointers) {
BackPointerElement elem = backPointers.get(curState);
if (elem == null || elem.getState().getScore() < curState.getScore()) {
minPriorityDecoderQueue.insert(curState, curState.getScore());
if (elem == null) {
backPointers.put(curState, new BackPointerElement(prevState, phrase));
} else {
elem.setState(prevState);
elem.setPhrase(phrase);
}
}
}
private List<ScoredPhrasePairForSentence> readBackPointers(
DecoderState state,
List<HashMap<DecoderState, BackPointerElement>> backPointersList,
int startLength,
int sentenceLength) {
DecoderState curState = state;
DecoderState startState = getStartState(sentenceLength);
int curLength = startLength;
List<ScoredPhrasePairForSentence> phrases = new ArrayList<>();
while (!curState.equals(startState)) {
BackPointerElement backPointer = backPointersList.get(curLength).get(curState);
phrases.add(0, backPointer.getPhrase());
curState = backPointer.getState();
curLength = decoderModel.getDecodedLength(curState);
}
return phrases;
}
