private boolean isAlive(String IPadr) {
String responseFromNode = null;
boolean result = true;
// Initialise socket and read/write
try {
socket = new Socket(IPadr, 4017);
sender = new PrintWriter(socket.getOutputStream(), true);
receiver = new BufferedReader(new InputStreamReader(socket.getInputStream()));
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// Ask the node if it is alive
sender.println(protocol.checkAliveQuery());
// Listen for a reply for timeoutDuration seconds
long startTime = System.currentTimeMillis();
long timeout = startTime + timeoutDuration;
while (System.currentTimeMillis() < timeout) {
try // will it wait here?
{
responseFromNode = receiver.readLine();
} catch (IOException e) {
e.printStackTrace();
}
// Break if the node answered
if (responseFromNode != null) break;
}
// Evaluate node reply
if (responseFromNode == null) result = false;
else if (responseFromNode == protocol.checkAliveResponse()) result = true;
// Close socket and read/write
try {
receiver.close();
sender.close();
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
