public void run() {
boolean flag = true;
while (flag) {
if (!isAlive(neighbours.getPreIp())) // Predecessor
updatePredecessor();
if (!isAlive(neighbours.getPrePreIp())) // PrePredecessor
updatePrePredecessor();
if (!isAlive(neighbours.getSucIp())) // Successor
updateSuccessor();
}
}
private void updatePrePredecessor() {
// Initialise socket and read/write
try {
socket = new Socket(neighbours.getPreIp(), 4017); // speaking to predecessor
sender = new PrintWriter(socket.getOutputStream(), true);
receiver = new BufferedReader(new InputStreamReader(socket.getInputStream()));
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// Ask for his predecessor
sender.println(protocol.getPredecessorQuery());
// Listen for his predecessor
String response = null;
try {
response = receiver.readLine();
} catch (IOException e) {
e.printStackTrace();
}
// If correct reply, update
if (response.contains(protocol.getPredecessorResponse())) {
int whiteSpace1 = response.indexOf(" ");
String usefulResponse = response.substring(whiteSpace1 + 1, response.length());
int whiteSpace2 = usefulResponse.indexOf(" ");
neighbours.setPrePreId(usefulResponse.substring(0, whiteSpace2));
neighbours.setPrePreIp(usefulResponse.substring(whiteSpace2 + 1, usefulResponse.length()));
}
// Close socket and read/write
try {
receiver.close();
sender.close();
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private void updateSuccessor() {
// Initialise socket and read/write
try {
socket = new Socket(neighbours.getSucSucIp(), 4017); // speaking to suc-successor
sender = new PrintWriter(socket.getOutputStream(), true);
receiver = new BufferedReader(new InputStreamReader(socket.getInputStream()));
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// Ask for his successor
sender.println(protocol.getSuccessorQuery());
// Listen for his successor
String response = null;
try {
response = receiver.readLine();
} catch (IOException e) {
e.printStackTrace();
}
// If correct reply, update
if (response.contains(protocol.getSuccessorResponse())) {
// Assign suc-successor to successor
neighbours.setSucId(neighbours.getSucSucId());
neighbours.setSucIp(neighbours.getSucSucIp());
// Assign sucsuccessor's sucessor to the sucsuccessor
int firstWhiteSpace = response.indexOf(" ");
String usefulResponse = response.substring(firstWhiteSpace + 1, response.length());
int secondWhiteSpace = usefulResponse.indexOf(" ");
neighbours.setSucSucId(usefulResponse.substring(0, secondWhiteSpace));
neighbours.setSucSucIp(
usefulResponse.substring(secondWhiteSpace + 1, usefulResponse.length()));
}
// Close socket and read/write
try {
receiver.close();
sender.close();
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
