/**
* Initializes and binds a socket that on a random port number. The method would try to bind on a
* random port and retry 5 times until a free port is found.
*
* @return the socket that we have initialized on a randomport number.
*/
private DatagramSocket initRandomPortSocket() {
DatagramSocket resultSocket = null;
String bindRetriesStr =
NetaddrActivator.getConfigurationService().getString(BIND_RETRIES_PROPERTY_NAME);
int bindRetries = 5;
if (bindRetriesStr != null) {
try {
bindRetries = Integer.parseInt(bindRetriesStr);
} catch (NumberFormatException ex) {
logger.error(
bindRetriesStr
+ " does not appear to be an integer. "
+ "Defaulting port bind retries to "
+ bindRetries,
ex);
}
}
int currentlyTriedPort = NetworkUtils.getRandomPortNumber();
// we'll first try to bind to a random port. if this fails we'll try
// again (bindRetries times in all) until we find a free local port.
for (int i = 0; i < bindRetries; i++) {
try {
resultSocket = new DatagramSocket(currentlyTriedPort);
// we succeeded - break so that we don't try to bind again
break;
} catch (SocketException exc) {
if (exc.getMessage().indexOf("Address already in use") == -1) {
logger.fatal(
"An exception occurred while trying to create" + "a local host discovery socket.",
exc);
resultSocket = null;
return null;
}
// port seems to be taken. try another one.
logger.debug("Port " + currentlyTriedPort + " seems in use.");
currentlyTriedPort = NetworkUtils.getRandomPortNumber();
logger.debug("Retrying bind on port " + currentlyTriedPort);
}
}
return resultSocket;
}
