private void handleIncomingConfirmableCoapRequest(ChannelHandlerContext ctx, MessageEvent me) {
InetSocketAddress remoteEndpoint = (InetSocketAddress) me.getRemoteAddress();
CoapMessage coapMessage = (CoapMessage) me.getMessage();
IncomingReliableMessageExchange newMessageExchange =
new IncomingReliableMessageExchange(remoteEndpoint, coapMessage.getMessageID());
IncomingMessageExchange oldMessageExchange =
ongoingMessageExchanges.get(remoteEndpoint, coapMessage.getMessageID());
// Check if there is an ongoing
if (oldMessageExchange != null) {
if (oldMessageExchange instanceof IncomingReliableMessageExchange) {
// if the old message exchange is reliable and the empty ACK was already sent send another
// empty ACK
if (((IncomingReliableMessageExchange) oldMessageExchange).isAcknowledgementSent())
writeEmptyAcknowledgement(remoteEndpoint, coapMessage.getMessageID());
}
// if the old message was unreliable and the duplicate message is confirmable send empty ACK
else writeEmptyAcknowledgement(remoteEndpoint, coapMessage.getMessageID());
// As the message is already being processed there is nothing more to do
return;
}
// try to add new reliable message exchange
boolean added = false;
synchronized (monitor) {
Long time = System.currentTimeMillis() + MIN_EMPTY_ACK_DELAY_MILLIS;
// Add message exchange to set of ongoing exchanges to detect duplicates
if (!ongoingMessageExchanges.contains(remoteEndpoint, coapMessage.getMessageID())) {
ongoingMessageExchanges.put(remoteEndpoint, coapMessage.getMessageID(), newMessageExchange);
added = true;
}
// If the scheduling of the empty ACK does not work then it was already scheduled
if (!emptyAcknowledgementSchedule.put(time, newMessageExchange)) {
log.error("Could not schedule empty ACK for message: {}", coapMessage);
ongoingMessageExchanges.remove(remoteEndpoint, coapMessage.getMessageID());
added = false;
}
}
// everything is fine, so further process message
if (added) ctx.sendUpstream(me);
}
private void handleOutgoingCoapResponse(ChannelHandlerContext ctx, MessageEvent me) {
CoapResponse coapResponse = (CoapResponse) me.getMessage();
InetSocketAddress remoteEndpoint = (InetSocketAddress) me.getRemoteAddress();
IncomingMessageExchange messageExchange;
synchronized (monitor) {
messageExchange = ongoingMessageExchanges.remove(remoteEndpoint, coapResponse.getMessageID());
}
if (messageExchange instanceof IncomingReliableMessageExchange) {
// if the ongoing message exchange is reliable and the empty ACK was not yet sent make
// response piggy-
// backed and suppress scheduled empty ACK
if (!((IncomingReliableMessageExchange) messageExchange).isAcknowledgementSent()) {
coapResponse.setMessageType(MessageType.Name.ACK.getNumber());
((IncomingReliableMessageExchange) messageExchange).setAcknowledgementSent();
}
}
ctx.sendDownstream(me);
}
