/**
* Dispatch a serialized command to the BackEnd and get back a serialized response. Mutual
* exclusion with itself to preserve dispatching order
*/
public synchronized byte[] dispatch(byte[] payload, boolean flush) throws ICPException {
// Note that we don't even try to dispatch packets while the
// device is not reachable to preserve dispatching order.
// If dispatching succeeded in fact this command would overcome
// any postponed command waiting to be flushed.
if (myDisconnectionManager.isReachable()) {
// The following check preserves dispatching order when the
// device has just reconnected but flushing has not started yet
if (waitingForFlush && !flush) {
throw new ICPException("Upsetting dispatching order");
}
waitingForFlush = false;
int sid = outCnt;
outCnt = (outCnt + 1) & 0x0f;
myLogger.log(Logger.FINE, "Issuing outgoing command " + sid);
try {
JICPPacket pkt =
new JICPPacket(JICPProtocol.COMMAND_TYPE, JICPProtocol.DEFAULT_INFO, payload);
pkt.setSessionID((byte) sid);
pkt = deliver(pkt);
myLogger.log(Logger.FINE, "Response received " + pkt.getSessionID());
if (pkt.getType() == JICPProtocol.ERROR_TYPE) {
// Communication OK, but there was a JICP error on the peer
throw new ICPException(new String(pkt.getData()));
}
return pkt.getData();
} catch (IOException ioe) {
// Can't reach the BackEnd. Assume we are unreachable
myLogger.log(Logger.WARNING, "IOException on output connection", ioe);
myDisconnectionManager.setUnreachable(false);
throw new ICPException("Dispatching error.", ioe);
}
} else {
throw new ICPException("Unreachable");
}
}
/**
* Make this HTTPFEDispatcher terminate. Note that when the BackEnd receives the termination
* notification (explicitly sent in case of a self-initiated shutdown or attached to the response
* to the EXIT command), it closes the input connection. The InputManager gets an exception and,
* since it has been killed, terminates.
*/
public void shutdown() {
terminator = Thread.currentThread();
myLogger.log(
Logger.INFO,
"Dispatcher shutting down. Self-initiated = " + (terminator != myInputManager));
if (terminator != myInputManager) {
// Self-initiated shut down
// If connected, explicitly notify the BackEnd.
if (myDisconnectionManager.isReachable()) {
JICPPacket pkt =
new JICPPacket(JICPProtocol.COMMAND_TYPE, (byte) (JICPProtocol.DEFAULT_INFO), null);
myLogger.log(Logger.INFO, "Pushing termination notification");
try {
deliver(pkt);
} catch (IOException ioe) {
// When the BackEnd receives the termination notification,
// it just closes the connection --> we always have this exception
myLogger.log(Logger.FINE, "BackEnd closed");
}
}
// Kill the InputManager
myInputManager.kill();
}
}
