/// <summary>
/// Method to do distributed sign off operation from the network.
/// </summary>
/// <param name="nodeID">ID of node that should be removed from the network</param>
/// <returns></returns>
public string signOffNode(int nodeID)
{
StringBuilder result = new StringBuilder("");
string nodeIPToBeSignedOff = Server.getInstance().getNetwork()[nodeID];
result.Append(Utils.logTimestamp(0) + nodeIPToBeSignedOff
+ " wants to sign off from the network" + "\n");
//Server.getInstance() will return the singleton that were created before
//removeHost will remove the host from network with given ip
Server.getInstance().removeHost(nodeIPToBeSignedOff);
//now it is time to remove the client with given ip from clients list
Server.getInstance().removeClientByIP(nodeIPToBeSignedOff);
Server.getInstance().resetNodesForCoordinatorElection();
//if all clients has been signed off from the network reset the next priority
//for new joining clients in the future
if (Server.getInstance().getClients().Count == 0)
{
Server.getInstance().resetNextPriority();
}
// helper method which help to enumerate clients' priorities
// in the case of 1, 2, 4 to 1, 2, 3 because 3rd node has been signed off
Server.getInstance().enumerateClientsPriorities();
result.Append(Utils.logTimestamp(0) + "\n");
Array.ForEach(Server.getInstance().getNodeArray(), s => result.AppendLine(s));
return(result.ToString());
}
/// <summary>
/// This method shows all the nodes in the network with specified ids.
/// </summary>
public static void showNetwork()
{
object response = null;
try
{
//temporary client for executing showNetworkState message
Client client = new Client(Server.getInstance().getSocketAddress(),
Utils.getDefaultSocketAddress());
//execute showNetworkState method on server's handler
IRequestProcessor cl = client.nodeList.Values.Last();
response = cl.showNetworkState();
if (response != null)
{
Console.WriteLine(response);
}
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in execution of remote showNetworkState() method");
}
beautifyOutput();
}
/// <summary>
/// This methoc checks host's ip address's eligibility
/// </summary>
/// <param name="IP">Address that user enters</param>
/// <returns></returns>
private static bool checkHostEligibility(string IP)
{
// check whether or not there is at least one host in the
// network
bool isHostWithGivenIPEligible = false;
// create the temporary client with server socket address and
// its own socket address and do remote procedure call
try
{
Client client = new Client(Server.getInstance().getSocketAddress(),
Utils.getDefaultSocketAddress());
//send the given ip to request processor to check whether
//the host with given ip already exists, if exists
//response will false
IRequestProcessor node = client.nodeList.Values.Last();
object response = node.checkHostEligibility(IP);
isHostWithGivenIPEligible = (bool)response;
}
catch (Exception e1)
{
Console.WriteLine("Exception in executing method "
+ "RequestProcessor.checkHostEligibility");
}
return(isHostWithGivenIPEligible);
}
/// <summary>
/// Helper method to simulate the entrance to critical section
/// </summary>
/// <param name="entererIP"></param>
/// <param name="word"></param>
/// <returns></returns>
public string enterCS(string entererIP, string word)
{
string newMasterStirng = Server.getInstance().getMasterNode().writeToMasterString(word);
return("Node " + entererIP + " has written " + "\"" + word + "\""
+ " to master string: " + newMasterStirng + "\n");
}
/*
* /// <summary>
* /// Method to achieve message propagation to all nodes in the network.
* /// </summary>
* /// <param name="methodName"></param>
* /// <returns></returns>
* public static object propagateMessageToAll(string methodName)
*
* {
*
* Client client = new Client(Server.getInstance().getSocketAddress(),Utils.getDefaultSocketAddress());
* IHelloService node = client.nodeList.Values.Last();
* return node.propagateJoinRequest(methodName);
*
* }*/
/// <summary>
/// Shows each node with IP address.
/// </summary>
private static void checkClients()
{
foreach (Client cl in Server.getInstance().getClients())
{
Console.WriteLine("Client " + cl.getIP());
}
}
//helper method for request sending to all nodes other than this
//Used by ------- Ricart & Agrawala Algorithm -------
public string sendmessage(string message, string requesterIP,
int requesterTimestamp, string receiverIP)
{
Client client = Server.getInstance().getClientByIP(receiverIP);
return(client.receiveMessage(message, requesterIP, requesterTimestamp));
}
public string checkAddressTables()
{
StringBuilder sb = new StringBuilder("");
// check whether the clients' address table has been updated
foreach (Client cl in Server.getInstance().getClients())
{
sb.Append(getConvenientOutput());
sb.Append("Client " + cl.getIP() + " address table:\n");
foreach (string address in cl.getAddressTable())
{
if (cl.getCoordinatorIP().Equals(address))
{
sb.Append(address + " *COORDINATOR*" + "\n");
}
else
{
sb.Append(address + "\n");
}
}
sb.Append(getConvenientOutput());
}
return(sb.ToString());
}
/// <summary>
/// This method returns server IP and list of clients' IP with IDs in network.
/// </summary>
/// <returns>Server IP and list of clients' IP with ID in network</returns>
public string showNetworkState()
{
StringBuilder result = new StringBuilder("");
int nodeId = 0;
string[] nodes = Server.getInstance().getNodeArray();
foreach (string nodeIP in nodes)
{
if (nodeId == 0)
{
result.Append("Server " + nodeId + " - " + nodeIP + "\n");
nodeId++;
}
else
{
if (Server.getInstance().getMasterNode().getIP().Equals(nodeIP, StringComparison.InvariantCultureIgnoreCase))
{
result.Append("Host " + nodeId + " - " + nodeIP + " [COORDINATOR]" + "\n");
}
else
{
result.Append("Host " + nodeId + " - " + nodeIP + "\n");
}
nodeId++;
}
}
return(result.ToString());
}
/// <summary>
/// This method propagates start message in the network for distributed read write operation.
/// </summary>
/// <returns></returns>
public string startDistributedReadWrite()
{
foreach (Client client in Server.getInstance().getClients())
{
client.setCanStartDistributedReadWriteOperations(true);
}
return("Start message propagated and nodes can start distributed read"
+ " and write operations\n");
}
/// <summary>
/// Updates address table with the ip addresses of the hosts in the network
/// </summary>
public void updateAddressTable()
{
List <string> network = Server.getInstance().getNetwork();
addressTable.Clear();
foreach (string IP in network.Skip(1).Take(network.Count)) //network.GetRange(0, network.Count))
{
addressTable.Add(IP);
}
}
/// <summary>
/// This method is for making each node in the network to know about the coordinator ip
/// </summary>
public void updateCoordinator()
{
if (Server.getInstance().getMasterNode() != null)
{
coordinatorIP = Server.getInstance().getMasterNode().getIP();
}
else
{
Console.WriteLine("Master node has not been assigned yet, so coordinator ip is null");
coordinatorIP = null;
}
}
/// <summary>
/// This method propagates join request.
/// </summary>
/// <param name="nodeSocketAddress">Socket address of node</param>
/// <returns></returns>
public string propagateJoinRequest(string nodeSocketAddress)
{
StringBuilder result = new StringBuilder("");
foreach (Client client in Server.getInstance().getClients())
{
client.updateAddressTable();
}
result.Append("New host is joined to network. Hosts in network:" + "\n");
Array.ForEach(Server.getInstance().getNodeArray(), s => result.AppendLine(s));
result.Append("Join message propagated and address table of each client updated" + "\n");
return(result.ToString());
}
/// <summary>
/// This method is for updating 'clients' list.
/// </summary>
/// <param name="clientSocketAddress">Socket address of client</param>
public void updateClientList(string clientSocketAddress)
{
try
{
Client client = new Client(getSocketAddress(), clientSocketAddress);
client.setPriority(Server.getInstance().getNextPriority());
clients.Add(client);
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in updating client's list on the server."
+ "\nClient's list will not be changed");
}
}
/// <summary>
/// This method does distributed join in the network.
/// </summary>
/// <param name="nodeSocketAddress">Socket address of node</param>
/// <returns></returns>
public string joinNode(string nodeSocketAddress)
{
StringBuilder result = new StringBuilder("");
result.Append(Utils.logTimestamp(0) + nodeSocketAddress + " wants to join the network" + "\n");
Server.getInstance().addHost(nodeSocketAddress);
Server.getInstance().updateClientList(nodeSocketAddress);
Server.getInstance().resetNodesForCoordinatorElection();
Server.getInstance().enumerateClientsPriorities();
result.Append(Utils.logTimestamp(0) + "\n");
Array.ForEach(Server.getInstance().getNodeArray(), s => result.AppendLine(s));
return(result.ToString());
}
/// <summary>
/// Updates address table with the ip addresses of the hosts in the network
/// </summary>
public void updateAddressTable()
{
List <string> network = Server.getInstance().getNetwork();
addressTable.Clear();
foreach (string IP in network.Skip(1).Take(network.Count)) //network.GetRange(0, network.Count))
{
addressTable.Add(IP);
}
/*
* Console.WriteLine("Address table of hosts in the network:");
* foreach(string a in addressTable)
* {
* Console.WriteLine(a);
* }*/
}
/// <summary>
/// This method propagates 'signOff' request in the network.
/// </summary>
/// <param name="nodeID">ID of node that signed off</param>
/// <returns></returns>
public string propagateSignOffRequest(int nodeID)
{
StringBuilder result = new StringBuilder("");
// all remaining clients will update their address table
foreach (Client client in Server.getInstance().getClients())
{
// by the address table client knows about other clients
client.updateAddressTable();
}
result.Append("Host is removed from network " + "\n");
Array.ForEach(Server.getInstance().getNodeArray(), s => result.AppendLine(s));
result.Append("SignOff message propagated and address table of each client updated" + "\n");
return(result.ToString());
}
public void run()
{
// if everything in critical section was OK
// send "release" message to the coordinator
Client client = new Client(Server.getInstance().getSocketAddress(), Utils.getDefaultSocketAddress());
try
{
node = client.nodeList.Values.Last();
node.sendMessage("release", client.getIP());
}
catch (Exception e)
{
Console.WriteLine("Exception while calling method"
+ " RequestProcessor.sendMessage "
+ "with message RELEASE\n");
}
}
/// <summary>
/// Helper method that each node will read final string at the end and write it to the screen.
/// Will also check the words they have added exist in the final string.
/// </summary>
/// <returns></returns>
public string readFinalString()
{
StringBuilder result = new StringBuilder("");
string finalString = null;
//each client will read the final string from master node and
//check whether their words that have been written exists in it
foreach (Client client in Server.getInstance().getClients())
{
Console.WriteLine(getConvenientOutput());
result.Append(getConvenientOutput());
//first get master string from master node
finalString = Server.getInstance().getMasterNode().getMasterString();
//output what has been read
Console.WriteLine("Client " + client.getIP() + " read final string: "
+ finalString + "\n");
result.Append("Client " + client.getIP() + " read final string: "
+ finalString + "\n");
//now output what client has been written to final string
Console.WriteLine("Client " + client.getIP() + " has written the following words:\n");
result.Append("Client " + client.getIP() + " has written the following words:\n");
int wordId = 1;
//enumerate words
foreach (string word in client.getWrittenWords())
{
Console.WriteLine(wordId + " " + "\"" + word + "\""
+ " exists in final string: " + finalString.Contains(word) + "\n");
result.Append(wordId + " " + "\"" + word + "\""
+ " exists in final string: " + finalString.Contains(word) + "\n");
wordId++;
}
getConvenientOutput();
}
return(result.ToString());
}
/// <summary>
/// Helper method to detect whether the address tables have been updated.
/// </summary>
private static void checkAddressTables()
{
// create the temporary client with server socket address and
// its own socket address and do remote procedure call
try
{
Client client = new Client(Server.getInstance().getSocketAddress(),
Utils.getDefaultSocketAddress());
IRequestProcessor node = client.nodeList.Values.Last();
// send the given ip to request processor to check whether
// the host with given ip already exists, if exists
// response will be false
object response = node.checkAddressTables();
Console.WriteLine((string)response);
}
catch (Exception e1)
{
Console.Error.WriteLine("Exception in executing method "
+ "RequestProcessor.checkAddressTables");
}
}
/// <summary>
/// Method to propagate coordinator message on the network.
/// </summary>
/// <param name="starterIP"></param>
/// <returns></returns>
public string propagateCoordinatorMessage(string starterIP)
{
StringBuilder result = new StringBuilder("");
//boolean variable to ensure whether the election has happened
//if happened we will have at least one client in the list
bool isElectionHappened = false;
//for each client update their coordinator ips
foreach (Client client in Server.getInstance().getClients())
{
client.updateCoordinator();
isElectionHappened = true;
}
//check whether election has happened print out the coordinator success message
if (isElectionHappened)
{
result.Append("Coordinator message propagated and now each node knows about the new coordinator" + "\n");
}
return(result.ToString());
}
/// <summary>
/// Master node election.
/// </summary>
/// <param name="actionStarterIPBundle"></param>
/// <returns></returns>
public string startElection(string actionStarterIPBundle)
{
resultStringToBeReturned = "";
Client starterClient = null;
//split the string
string[] components = actionStarterIPBundle.Split(',');
string action = components[0];
string starterIP = components[1];
try
{
// we will handle master election in two cases.
if (action.Equals("join", StringComparison.InvariantCultureIgnoreCase))
{
starterClient = Server.getInstance().getClientByIP(starterIP);
}
else if (action.Equals("signOff", StringComparison.InvariantCultureIgnoreCase))
{
starterIP = Server.getInstance().getFirstRemainingClient().getIP();
starterClient = Server.getInstance().getClientByIP(starterIP);
}
}
catch (ArgumentOutOfRangeException ex)
{
resultStringToBeReturned += "There is no client in the network "
+ "please join at least one" + "\n";
}
clientsPriorities = new int[Server.getInstance().getClients().Count];
clientsStatuses = new bool[Server.getInstance().getClients().Count];
numberOfClients = Server.getInstance().getClients().Count;
int index = 0;
//now assign clientsPriorities and clientStatuses
foreach (Client client in Server.getInstance().getClients())
{
clientsPriorities[index] = client.getPriority();
clientsStatuses[index] = client.isStatus();
index++;
}
if (starterClient != null)
{
//priority is the same as the index + 1 of client in 'clients' list
elect(starterClient.getPriority());
//set this coordinator as master node
//coordinator number starts from 1, so we need index it to start from zero
Client masterClient = Server.getInstance().getClients()[coordinatorNumber - 1]; // CHECK - done!
masterClient.setMasterNode(true);
resultStringToBeReturned += "Final coordinator is node " + coordinatorNumber + " with IP " + masterClient.getIP() + "\n";
return(resultStringToBeReturned);
}
else
{
resultStringToBeReturned += "There is no starter client with given"
+ " properties to start master election" + "\n";
return(resultStringToBeReturned);
}
}
public void ruN(int index1)
{
StringBuilder result = new StringBuilder("");
List <Client> clientList = Server.getInstance().getShallowCopyClients();
Client[] clients = clientList.ToArray();
Client[] clientsOtherThanThis = Server.getInstance()
.getClientsArrayOtherThan(clients[index1]);
//set the state of this client to wanted, because
//it wants to access critical section
clients[index1].setWanted(true);
//and before submitting request, the client must update its
//logical clock, so
//update clock, which will increment default timestamp
//basically Ricart&Agrawala is using extended Lamport clock
//in extended lamport clock, for each send event, the node
//has to update its clock (increment timestamp)
clients[index1].updateClock();
Client clienT = new Client(Server.getInstance().getSocketAddress(), Utils.getDefaultSocketAddress());
object reply = null;
node = clienT.nodeList.Values.Last();
foreach (Client client in clientsOtherThanThis)
{
bool isRequestSendingOK = false;
try
{
Console.WriteLine("Client " + clients[index1].getIP()
+ " with timeStamp " + clients[index1].getClock()
+ " sending \"request\" to client " + client.getIP()
+ "\n");
result.Append("Client " + clients[index1].getIP()
+ " with timeStamp " + clients[index1].getClock()
+ " sending \"request\" to client " + client.getIP()
+ "\n");
reply = node.sendmessage("request", clients[index1].getIP(), clients[index1].getClock(), client.getIP());
//if we have reached here request sending has been successful
isRequestSendingOK = true;
}
catch (Exception e)
{
Console.WriteLine("Exception while executing the "
+ "RequestProcessor.sendMessage method for"
+ " each client other than this client");
result.Append("Exception while executing the "
+ "RequestProcessor.sendMessage method for"
+ " each client other than this client\n");
}
if (isRequestSendingOK)
{
//cast reply to string
string replyString = (string)reply;
if (replyString.Contains(","))
{
//now split and get OK sender's timestamp
string[] splitComponents = replyString.Split(',');
if (splitComponents[0].Equals("OK", StringComparison.InvariantCultureIgnoreCase))
{
//update the logical clock, when received OK
//from the other node, because it is receive event
clients[index1].updateClock(int.Parse(splitComponents[1]));
//increment the OK count for this client
clients[index1].incrementOKCount();
}
}
}
}
//so, number of OKCount is the same as number of clients
//other than this. In other words, if received "OK" from
//all clients that this client has sent the request to
while (clients[index1].getOKCount() != clientsOtherThanThis.Length)
{
//wait
}
if (clients[index1].getOKCount() == clientsOtherThanThis.Length)
{
//now this client can enter the critical section
//set the using flag for this client
clients[index1].setUsing(true);
Server.getInstance().assignToCriticalSection(clients[index1].getIP());
// get the random English word
string randomEnglishWord = Server.getInstance().generateRandomEnglishWord();
// method to write this generated word to
// client's
// buffer to check it later whether or not
// written
// word exists in the resulting master string
clients[index1].rememberWord(randomEnglishWord);
// now enter the critical section where the word
// will be written
// to the coordinator's master string
// boolean variable to hold whether
// criticalSection entrance was OK
bool isCriticalSectionSuccess = false;
try
{
// params will contain the client's ip who
// will enter
// the critical section and and the
// randomEnglishWord
reply = node.enterCS(clients[index1].getIP(), randomEnglishWord);
// reply could be like
// "Node with ip has written some word"
Console.WriteLine((string)reply);
result.Append((string)reply);
//if we have reached here critical section completed successfully
isCriticalSectionSuccess = true;
}
catch (Exception e)
{
Console.WriteLine("Exception while calling method"
+ " RequestProcessor.enterCS\n");
}
if (isCriticalSectionSuccess)
{
// update clock when sending OK
clients[index1].updateClock();
int oksSent = 0;
int numberOfNodesOkToBeSent = clients[index1].getRequestQueue().Count();
//get the queue, send OK to all processes in own queue
//and empty queue.
foreach (string IP in clients[index1].getRequestQueue())
{
try
{
result.Append("Client " + clients[index1].getIP()
+ " with timeStamp " + clients[index1].getClock()
+ " sending \"OK\" to client " + IP
+ "\n");
node.sendmessage("OK", clients[index1].getIP(), clients[index1].getClock(), IP);
oksSent++;
}
catch (Exception e)
{
Console.WriteLine("Exception while executing the "
+ "RequestProcessor.sendMessage method for"
+ " each client other than this client");
}
}
//if all oks sent successfully
if (oksSent == numberOfNodesOkToBeSent)
{
Server.getInstance().removeFromCriticalSection(clients[index1].getIP());
//now empty queue, set using and wanted flags to false
//and resetOKCount to 0.
clients[index1].emptyRequestQueue();
clients[index1].setUsing(false);
clients[index1].setWanted(false);
clients[index1].resetOKCount();
}
}
}
}
public string doRicartAgrawala()
{
StringBuilder result = new StringBuilder("");
//random instance to generate random amount of waiting time.
Random rand = new Random();
int startTime = Environment.TickCount;
int timeStamp = 0;
while (Environment.TickCount - startTime <= 20 * 1000)
{
//sleep a little bit
int timeToSleep = rand.Next(2) + 1;
try
{
result.Append(Utils.logTimestamp(timeStamp) + "sleep for "
+ timeToSleep + " seconds.\n");
Console.WriteLine(Utils.logTimestamp(timeStamp) + "sleep for "
+ timeToSleep + " seconds.\n");
//Suspends the current thread for the specified number of milliseconds.
Thread.Sleep(timeToSleep * 1000);
}
catch (Exception e)
{
Console.WriteLine("Exception on calling Thread.Sleep method");
}
//get the clients
List <Client> clientList = Server.getInstance().getShallowCopyClients();
Client[] clients = clientList.ToArray();
Thread[] threads = new Thread[clients.Length];
// performed by each client at initialization
//that state_Pi:= RELEASED
foreach (Client client in clientList)
{
client.setUsing(false);
client.setWanted(false);
client.resetOKCount();
client.resetClock();
client.emptyRequestQueue();
}
for (int i = 0; i < clients.Length; i++)
{
int index1 = i;
threads[i] = new Thread(delegate() { ruN(index1); }); //captures "index1" and uses that when the delegate is executed
}
// now start the threads concurrently
foreach (Thread thread in threads)
{
thread.Start();
}
foreach (Thread thread in threads)
{
try
{
thread.Join();
}
catch (Exception e)
{
Console.WriteLine("Interrupted exception in join call");
}
}
timeStamp++;
}
return(result.ToString());
}
static void Main(string[] args)
{
Client client = null;
IRequestProcessor node;
bool joinOK = false;
bool signOffOK = false;
Console.WriteLine("Enter server's socket address - IP:PORT ");
string serverSocketAddress = Console.ReadLine();
while (true)
{
if (Utils.isValidSocketAddress(Utils.getIPFromSocketAddress(serverSocketAddress)))
{
break;
}
else
{
serverSocketAddress = Console.ReadLine();
}
}
Server server = Server.getInstance(serverSocketAddress);
server.start();
while (true)
{
Console.WriteLine("Press ENTER to continue...");
try
{
Console.ReadLine();
showCommands();
}
catch (IOException e)
{
server.stop();
break;
}
int command = int.Parse(Console.ReadLine());
switch (command)
{
case 1:
{
if (server.isNetworkAvailable())
{
Console.WriteLine("Enter socket address of new host in form IP:PORT, that you want to join: ");
string socketAddress = Console.ReadLine();
while (true)
{
if (Utils.isValidSocketAddress(Utils.getIPFromSocketAddress(socketAddress)))
{
if (checkHostEligibility(Utils.getIPFromSocketAddress(socketAddress)))
{
Console.WriteLine("Host is already in the network! Type in another IP:PORT ");
socketAddress = Console.ReadLine();
}
else
{
break;
}
}
else
{
socketAddress = Console.ReadLine();
}
}
try
{
client = new Client(server.getSocketAddress(), socketAddress);
}
catch (Exception e)
{
Console.Error.WriteLine("Error Setting the server url for this client.");
client = null;
}
if (client != null)
{
object response = null;
beautifyOutput();
try
{
node = client.nodeList.Values.Last();
response = node.joinNode(client.getSocketAddress());
Console.WriteLine(response);
try
{
// propagatemessagetoall in java
response = node.propagateJoinRequest(client.getSocketAddress());
Console.WriteLine(response);
checkClients();
beautifyOutput();
joinOK = true;
}
catch (Exception e)
{
Console.Error.WriteLine("Failed to broadcast join request");
}
}
catch (Exception e)
{
Console.Error.WriteLine("Error executing join request, response is null");
}
if (joinOK)
{
Console.WriteLine("Master node Election ");
try
{
node = client.nodeList.Values.Last();
response = node.startElection("join" + "," + client.getIP());
if (response != null)
{
Console.WriteLine(response);
//propagatemessagetoall in java
response = node.propagateCoordinatorMessage(client.getIP());
Console.WriteLine(response);
beautifyOutput();
}
// Master election is done. because of it joinOK is false now.
joinOK = false;
}
catch (Exception e)
{
Console.Error.WriteLine("Failed to broadcast coordinator message");
}
}
}
else
{
Console.WriteLine("Try to correct server's socket address"
+ " or clients' socket address");
break;
}
}
else
{
Console.WriteLine("Please first add your server to the network");
}
break;
}
case 2:
{
if (server.isNetworkAvailable())
{
bool isOneHostAvailable = false;
try
{
client = new Client(server.getSocketAddress(),
Utils.getDefaultSocketAddress());
node = client.nodeList.Values.Last();
object response = node.atLeastOneHostAvailable();
isOneHostAvailable = (bool)response;
}
catch (Exception e1)
{
Console.WriteLine("Exception in executing method "
+ "RequestProcessor.atLeastOneHostAvailable");
}
if (isOneHostAvailable)
{
showNetwork();
Console.WriteLine("Enter the node ID to sign it off from the network:");
int nodeIdToSignOff = int.Parse(Console.ReadLine());
while (nodeIdToSignOff == 0)
{
Console.WriteLine("Server cannot be signed off from the network!" + "\n");
Console.WriteLine("Enter the node ID to sign it off from the network: ");
nodeIdToSignOff = int.Parse(Console.ReadLine());
}
try
{
client = new Client(server.getSocketAddress(),
Utils.getDefaultSocketAddress());
}
catch (Exception e)
{
Console.Error.WriteLine("Error Setting the server url for this client.");
client = null;
}
if (client != null)
{
object response = null;
beautifyOutput();
try
{
node = client.nodeList.Values.Last();
response = node.signOffNode(nodeIdToSignOff);
Console.WriteLine(response);
try
{
response = node.propagateSignOffRequest(nodeIdToSignOff);
Console.WriteLine(response);
beautifyOutput();
signOffOK = true;
}
catch (Exception e)
{
Console.WriteLine("Failed to broadcast signoff request");
}
}
catch (Exception e)
{
Console.WriteLine("Error executing signoff request, response is null");
}
if (signOffOK)
{
Console.WriteLine("Master Node Election: ");
try
{
node = client.nodeList.Values.Last();
response = node.startElection("signOff" + "," + Utils.getDefaultIP());
if (response != null)
{
Console.WriteLine(response);
response = node.propagateCoordinatorMessage(Utils.getDefaultIP());
Console.WriteLine(response);
beautifyOutput();
}
signOffOK = false;
}
catch (Exception e)
{
Console.WriteLine("Exception in master election process ");
}
}
}
else
{
Console.Error.WriteLine("Try to correct servers' socket address"
+ " or clients' socket address");
break;
}
}
else
{
Console.WriteLine("There is no host in the network, try to join at least one");
}
}
else
{
Console.WriteLine("Please first add your server to the network");
}
break;
}
case 3:
{
showNetwork();
Console.WriteLine("Do you want see address table of each client(Y/N): ");
string prompt = Console.ReadLine();
//check correctness of prompt
while (!(prompt.Equals("Y", StringComparison.InvariantCultureIgnoreCase) || prompt.Equals("N", StringComparison.InvariantCultureIgnoreCase)))
{
Console.WriteLine("Enter just Y or N: ");
prompt = Console.ReadLine();
}
if (prompt.Equals("Y", StringComparison.InvariantCultureIgnoreCase))
{
checkAddressTables();
}
break;
}
case 4:
{
if (server.isNetworkAvailable())
{
bool isOneHostAvailable = false;
try
{
client = new Client(server.getSocketAddress(),
Utils.getDefaultSocketAddress());
node = client.nodeList.Values.Last();
object response = node.atLeastOneHostAvailable();
isOneHostAvailable = (bool)response;
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in executing method "
+ "RequestProcessor.atLeastOneHostAvailable");
}
if (isOneHostAvailable) // then propagate start message to all nodes.
{
object response = null;
node = client.nodeList.Values.Last();
try
{
response = node.startDistributedReadWrite();
string reply = (string)response;
beautifyOutput();
Console.WriteLine(reply);
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in executing method "
+ "RequestProcessor.startDistributedReadWrite");
}
showAlgorithms();
Console.WriteLine("Enter synchronization algorithm ID to start: ");
int algorithmID = int.Parse(Console.ReadLine());
switch (algorithmID)
{
case 1:
{
//boolean variable to hold whether or not the algorithm worked
bool isCeMutExOK = false;
// we will start rpc call to do Centralized Mutual Exclusion method.
//create temporarily client.
try
{
node = client.nodeList.Values.Last();
response = node.doCeMutEx();
//print out what is returned
//Console.WriteLine((string)response);
isCeMutExOK = true;
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in execution of RequestProcessor.doCeMutEx() method");
}
//After process has ended all the nodes read the final string from
//master node and write it to the screen
//Moreover they check if all words they added to the string
//are present in the final string. The result of this check
//is also written to the screen.
if (isCeMutExOK)
{
// we will need a temporary client to
// execute readFinalString method
try
{
//execute readFinalString method on server's handler
response = node.readFinalString();
Console.WriteLine((string)response);
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in execution of "
+ "remote readFinalString() method");
}
}
break;
}
case 2:
{
//boolean variable to hold whether or not the algorithm worked
bool isRicartAgrawalaOK = false;
try
{
node = client.nodeList.Values.Last();
response = node.doRicartAgrawala();
//Console.WriteLine((string)response);
isRicartAgrawalaOK = true;
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in execution of remote "
+ "doRicartAgrawala() method");
}
//After process has ended all the nodes read the final string from
//master node and write it to the screen
//Moreover they check if all words they added to the string
//are present in the final string. The result of this check
//is also written to the screen.
if (isRicartAgrawalaOK)
{
try
{
response = node.readFinalString();
Console.WriteLine((string)response);
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in execution of "
+ "remote readFinalString() method");
}
}
break;
}
default:
{
Console.WriteLine("Please enter correct algorithm id ");
break;
}
}
}
else
{
Console.WriteLine("There is no Host in the network, try to join at least one. ");
}
}
else
{
Console.WriteLine("Please first add your server to the network. ");
}
break;
}
case 5:
{
server.stop();
Console.WriteLine("DONE");
Console.ReadLine();
return;
}
default:
{
break;
}
}
}
}
static void Main(string[] args)
{
Client client = null;
IRequestProcessor node;
bool joinOK = false;
bool signOffOK = false;
Console.WriteLine("Enter server's socket address - IP:PORT ");
string serverSocketAddress = Console.ReadLine();
while (true)
{
if (Utils.isValidSocketAddress(Utils.getIPFromSocketAddress(serverSocketAddress)))
{
break;
}
else
{
serverSocketAddress = Console.ReadLine();
}
}
Server server = Server.getInstance(serverSocketAddress);
server.start();
while (true)
{
Console.WriteLine("Press ENTER to continue...");
try
{
Console.ReadLine();
showCommands();
}
catch (IOException e)
{
server.stop();
break;
}
int command = int.Parse(Console.ReadLine());
switch (command)
{
case 1:
{
if (server.isNetworkAvailable())
{
Console.WriteLine("Enter socket address of new host in form IP:PORT, that you want to join: ");
string socketAddress = Console.ReadLine();
while (true)
{
if (Utils.isValidSocketAddress(Utils.getIPFromSocketAddress(socketAddress)))
{
if (checkHostEligibility(Utils.getIPFromSocketAddress(socketAddress)))
{
Console.WriteLine("Host is already in the network! Type in another IP:PORT ");
socketAddress = Console.ReadLine();
}
else
{
break;
}
}
else
{
socketAddress = Console.ReadLine();
}
}
try
{
client = new Client(server.getSocketAddress(), socketAddress);
}
catch (Exception e)
{
Console.Error.WriteLine("Error Setting the server url for this client.");
client = null;
}
if (client != null)
{
object response = null;
beautifyOutput();
try
{
node = client.nodeList.Values.Last();
response = node.joinNode(client.getSocketAddress());
Console.WriteLine(response);
try
{
// propagatemessagetoall in java
response = node.propagateJoinRequest(client.getSocketAddress());
Console.WriteLine(response);
checkClients();
beautifyOutput();
joinOK = true;
}
catch (Exception e)
{
Console.Error.WriteLine("Failed to broadcast join request");
}
}
catch (Exception e)
{
Console.Error.WriteLine("Error executing join request, response is null");
}
if (joinOK)
{
Console.WriteLine("Master node Election ");
try
{
node = client.nodeList.Values.Last();
response = node.startElection("join" + "," + client.getIP());
if (response != null)
{
Console.WriteLine(response);
//propagatemessagetoall in java
response = node.propagateCoordinatorMessage(client.getIP());
Console.WriteLine(response);
beautifyOutput();
}
// Master election is done. because of it joinOK is false now.
joinOK = false;
}
catch (Exception e)
{
Console.Error.WriteLine("Failed to broadcast coordinator message");
}
}
}
else
{
Console.WriteLine("Try to correct server's socket address"
+ " or clients' socket address");
break;
}
}
else
{
Console.WriteLine("Please first add your server to the network");
}
break;
}
case 2:
{
if (server.isNetworkAvailable())
{
bool isOneHostAvailable = false;
try
{
client = new Client(server.getSocketAddress(),
Utils.getDefaultSocketAddress());
node = client.nodeList.Values.Last();
object response = node.atLeastOneHostAvailable();
isOneHostAvailable = (bool)response;
}
catch (Exception e1)
{
Console.WriteLine("Exception in executing method "
+ "RequestProcessor.atLeastOneHostAvailable");
}
if (isOneHostAvailable)
{
showNetwork();
Console.WriteLine("Enter the node ID to sign it off from the network:");
int nodeIdToSignOff = int.Parse(Console.ReadLine());
while (nodeIdToSignOff == 0)
{
Console.WriteLine("Server cannot be signed off from the network!" + "\n");
Console.WriteLine("Enter the node ID to sign it off from the network: ");
nodeIdToSignOff = int.Parse(Console.ReadLine());
}
try
{
client = new Client(server.getSocketAddress(),
Utils.getDefaultSocketAddress());
}
catch (Exception e)
{
Console.Error.WriteLine("Error Setting the server url for this client.");
client = null;
}
if (client != null)
{
object response = null;
beautifyOutput();
try
{
node = client.nodeList.Values.Last();
response = node.signOffNode(nodeIdToSignOff);
Console.WriteLine(response);
try
{
response = node.propagateSignOffRequest(nodeIdToSignOff);
Console.WriteLine(response);
beautifyOutput();
signOffOK = true;
}
catch (Exception e)
{
Console.WriteLine("Failed to broadcast signoff request");
}
}
catch (Exception e)
{
Console.WriteLine("Error executing signoff request, response is null");
}
if (signOffOK)
{
Console.WriteLine("Master Node Election: ");
try
{
node = client.nodeList.Values.Last();
response = node.startElection("signOff" + "," + Utils.getDefaultIP());
if (response != null)
{
Console.WriteLine(response);
response = node.propagateCoordinatorMessage(Utils.getDefaultIP());
Console.WriteLine(response);
beautifyOutput();
}
signOffOK = false;
}
catch (Exception e)
{
Console.WriteLine("Exception in master election process ");
}
}
}
else
{
Console.Error.WriteLine("Try to correct servers' socket address"
+ " or clients' socket address");
break;
}
}
else
{
Console.WriteLine("There is no host in the network, try to join at least one");
}
}
else
{
Console.WriteLine("Please first add your server to the network");
}
break;
}
case 3:
{
showNetwork();
break;
}
case 4:
{
break;
}
case 5:
{
server.stop();
Console.WriteLine("DONE");
Console.ReadLine();
return;
}
default:
{
break;
}
}
}
}
public void run(int index)
{
StringBuilder result = new StringBuilder("");
List <Client> clientList = Server.getInstance().getShallowCopyClients();
Client[] clients = clientList.ToArray();
IRequestProcessor node;
Client client = new Client(Server.getInstance().getSocketAddress(), Utils.getDefaultSocketAddress());
// boolean variable to achieve consistency in the code
bool isMessageSendOk = false;
node = client.nodeList.Values.Last();
// reply will contains the string GRANTED or DENIED
object reply = null;
try
{
reply = node.sendMessage("request", clients[index].getIP());
isMessageSendOk = true;
}
catch (Exception e)
{
Console.Error.WriteLine("Exception in executing the "
+ "RequestProcessor.sendMessage method\n");
result.Append("Exception in executing the "
+ "RequestProcessor.sendMessage method\n");
}
if (isMessageSendOk)
{
string replyString = (string)reply;
// if reply was GRANTED
if (replyString.Equals("GRANTED", StringComparison.InvariantCultureIgnoreCase))
{
string randomEnglishWord = Server.getInstance().generateRandomEnglishWord();
clients[index].rememberWord(randomEnglishWord);
// boolean variable to hold whether
// criticalSection entrance was OK
bool isCriticalSectionSuccess = false;
try
{
reply = node.enterCS(clients[index].getIP(),
randomEnglishWord);
// reply could be like
// "Node with ip has written some word"
Console.WriteLine((string)reply);
result.Append((string)reply);
isCriticalSectionSuccess = true;
}
catch (Exception e)
{
Console.Error.WriteLine("Exception while calling method"
+ " RequestProcessor.enterCS\n");
result.Append("Exception while calling method"
+ " RequestProcessor.enterCS\n");
}
// if everything in critical section was OK
// send "release" message to the coordinator
if (isCriticalSectionSuccess)
{
Console.WriteLine(clients[index].getIP()
+ " sending \"release\" message\n");
result.Append(clients[index].getIP()
+ " sending \"release\" message\n");
try
{
node.sendMessage("release", clients[index].getIP());
}
catch (Exception e)
{
Console.WriteLine("Exception while calling method"
+ " RequestProcessor.sendMessage with message RELEASE\n");
result.Append("Exception while calling method"
+ " RequestProcessor.sendMessage with message RELEASE\n");
}
}
}
}
}
// public static int index;
/// <summary>
/// This method implements Centralized Mutual Exclusion Algortihm.
/// </summary>
/// <returns></returns>
public string doCeMutEx()
{
StringBuilder result = new StringBuilder("");
//random instance to generate random amount of waiting time.
Random rand = new Random();
//Gets the number of milliseconds elapsed since the system started.
int startTime = Environment.TickCount;
int timeStamp = 0;
while (Environment.TickCount - startTime <= 20 * 1000)
{
//sleep a little bit
int timeToSleep = rand.Next(2) + 1;
try
{
result.Append(Utils.logTimestamp(timeStamp) + "sleep for "
+ timeToSleep + " seconds.\n");
Console.WriteLine(Utils.logTimestamp(timeStamp) + "sleep for "
+ timeToSleep + " seconds.\n");
//Suspends the current thread for the specified number of milliseconds.
Thread.Sleep(timeToSleep * 1000);
}
catch (Exception e)
{
Console.WriteLine("Exception on calling Thread.Sleep method");
}
//get the clients
List <Client> clientList = Server.getInstance().getShallowCopyClients();
Client[] clients = clientList.ToArray();
Thread[] threads = new Thread[clients.Length];
for (int i = 0; i < clients.Length; i++)
{
int index = i;
threads[i] = new Thread(delegate() { run(index); }); //captures "index" and uses that when the delegate is executed
}
//now start the threads concurrently
foreach (Thread thread in threads)
{
thread.Start();
}
// Now everything's running - join all the threads
// started to all the threads you want to run in parallel,
// then call join on them all
// this will prevent threads run sequentially.
foreach (Thread thread in threads)
{
try
{
thread.Join();
}
catch (Exception e)
{
Console.WriteLine("Exception in join call");
}
}
timeStamp++;
}
// sleep here for 10 seconds before all threads finish the job
try
{
Thread.Sleep(10 * 1000);
}
catch (Exception e)
{
Console.WriteLine("Exception in Thread.sleep call");
}
return(result.ToString());
}
/// <summary>
/// This method checks if there at least one host in network.
/// </summary>
/// <returns></returns>
public bool atLeastOneHostAvailable()
{
return(Server.getInstance().atLeastOneHostAvailable());
}
/// <summary>
/// This method returns true or false depending if new joining client is in the network or not.
/// </summary>
/// <param name="IP">IP address of host</param>
/// <returns>bool value</returns>
public bool checkHostEligibility(string IP)
{
return(Server.getInstance().checkHostEligibility(IP));
}
/// <summary>
/// Helper method for message send to the coordinator.
/// </summary>
/// <param name="message"></param>
/// <param name="requesterIP"></param>
/// <returns></returns>
public string sendMessage(string message, string requesterIP)
{
//call the receiveMessage method in coordinator
return(Server.getInstance().getMasterNode().receiveMessage(message, requesterIP));
}