Client now asks servers to tracker !

src/clientP2P/ClientManagementTCP.java

@@ -31,6 +31,8 @@ import clientP2P.ClientDownloadTCP;
 import tools.HostItem;
 import tools.Logger;
 import tools.LogLevel;
+import protocolP2P.DiscoverRequest;
+import protocolP2P.DiscoverResponse;
 
 /** Implementation of P2P-JAVA-PROJECT CLIENT
  * @author	Louis Royer
@@ -42,26 +44,36 @@ public class ClientManagementTCP implements Runnable {
 	private String baseDirectory;
 	private String partsSubdir;
 	private List<HostItem> hostList;
+	private HostItem tracker;
 	private Logger logger;
+	private Scanner scanner;
 
-	/** Constructor for TCP implementation, with baseDirectory and TCPPort parameters.
+	/** Constructor for TCP implementation, with baseDirectory, tracker, partsSubdir, logger, and scanner parameters.
 	 * @param baseDirectory	the root directory where files are stored
-	 * @param host	hostname of the server
-	 * @param TCPPort	the server will listen on this port
+	 * @param tracker Tracker hostItem
+	 * @param partsSubdir	subdirectory to store file parts
+	 * @param logger	Loggger
+	 * @param scanner	Scanner used to read input
 	 */
-	public ClientManagementTCP(String baseDirectory, List<HostItem> hostList, String partsSubdir, Logger logger) {
+	public ClientManagementTCP(String baseDirectory, HostItem tracker, String partsSubdir, Logger logger, Scanner scanner) {
+		this.scanner = scanner;
 		this.baseDirectory = baseDirectory;
-		this.hostList = hostList;
+		this.tracker = tracker;
 		this.partsSubdir = partsSubdir;
 		this.logger = logger;
+		try {
+			initHostList();
+		} catch (InternalError e) {
+			System.exit(-1);
+		} catch (ProtocolError e) {
+			System.exit(-2);
+		}
 	}
 
 	/** Implementation of Runnable
 	 */
 	public void run() {
 		try {
-			System.out.println("Enter all servers: type \"stop\" when finished");
-			Scanner scanner = new Scanner(System.in);
 			String[] list = listDirectory();
 			System.out.println("Files present on the server:");
 			for(String listItem: list) {
@@ -69,49 +81,35 @@ public class ClientManagementTCP implements Runnable {
 			}
 			System.out.println("Name of the file to download:");
 			String f = scanner.nextLine();
-			scanner.close();
 			download(f);
 			System.out.println("File " + f + " sucessfully downloaded");
 			logger.writeTCP("File " + f + " sucessfully downloaded", LogLevel.Info);
 		} catch (EmptyDirectory e) {
-			System.err.println("Error: Server has no file in directory");
-			logger.writeTCP("Error: Server has no file in directory", LogLevel.Error);
+			logger.writeTCP("Server has no file in directory", LogLevel.Error);
 		} catch (InternalError e) {
-			System.err.println("Error: Client internal error");
-			logger.writeTCP("Error: Client internal error", LogLevel.Error);
+			logger.writeTCP("Client internal error", LogLevel.Error);
 		} catch (UnknownHostException e) {
-			System.err.println("Error: Server host is unknown");
-			logger.writeTCP("Error: Server host is unknown", LogLevel.Error);
+			logger.writeTCP("Server host is unknown", LogLevel.Error);
 		} catch (IOException e) {
-			System.err.println("Error: Request cannot be send or response cannot be received");
-			logger.writeTCP("Error: Request cannot be send or response cannot be received", LogLevel.Error);
+			logger.writeTCP("Request cannot be send or response cannot be received", LogLevel.Error);
 		} catch (TransmissionError e) {
-			System.err.println("Error: Message received is too big");
-			logger.writeTCP("Error: Message received is too big", LogLevel.Error);
+			logger.writeTCP("Message received is too big", LogLevel.Error);
 		} catch (ProtocolError e) {
-			System.err.println("Error: Cannot decode server’s response");
-			logger.writeTCP("Error: Cannot decode server’s response", LogLevel.Error);
+			logger.writeTCP("Cannot decode server’s response", LogLevel.Error);
 		} catch (VersionError e) {
-			System.err.println("Error: Server’s response use bad version of the protocol");
-			logger.writeTCP("Error: Server’s response use bad version of the protocol", LogLevel.Error);
+			logger.writeTCP("Server’s response use bad version of the protocol", LogLevel.Error);
 		} catch (SizeError e) {
-			System.err.println("Error: Cannot handle this packets because of internal representation limitations of numbers on the client");
-			logger.writeTCP("Error: Cannot handle this packets because of internal representation limitations of numbers on the client", LogLevel.Error);
+			logger.writeTCP("Cannot handle this packets because of internal representation limitations of numbers on the client", LogLevel.Error);
 		} catch (InternalRemoteError e) {
-			System.err.println("Error: Server internal error");
-			logger.writeTCP("Error: Server internal error", LogLevel.Error);
+			logger.writeTCP("Server internal error", LogLevel.Error);
 		} catch (ProtocolRemoteError e) {
-			System.err.println("Error: Server cannot decode client’s request");
-			logger.writeTCP("Error: Server cannot decode client’s request", LogLevel.Error);
+			logger.writeTCP("Server cannot decode client’s request", LogLevel.Error);
 		} catch (VersionRemoteError e) {
-			System.err.println("Error: Server cannot decode this version of the protocol");
-			logger.writeTCP("Error: Server cannot decode this version of the protocol", LogLevel.Error);
+			logger.writeTCP("Server cannot decode this version of the protocol", LogLevel.Error);
 		} catch (NotFound e) {
-			System.err.println("Error: Server has not this file in directory");
-			logger.writeTCP("Error: Server has not this file in directory", LogLevel.Error);
+			logger.writeTCP("Server has not this file in directory", LogLevel.Error);
 		} catch (EmptyFile e) {
-			System.err.println("Error: File is empty");
-			logger.writeTCP("Error: File is empty", LogLevel.Error);
+			logger.writeTCP("File is empty", LogLevel.Error);
 		}
 	}
 
@@ -139,21 +137,18 @@ public class ClientManagementTCP implements Runnable {
 			if (downLoader.getSuccess()) {
 				byte[] hash512 = downLoader.getHashSum512();
 				if (!Arrays.equals(hash512, computeHashsum(filename, HashAlgorithm.SHA512))) {
-					System.err.println("Error: Hashsum does not match");
-					logger.writeTCP("Error: Hashsum does not match", LogLevel.Error);
-					System.err.println("Computed checksum:");
+					logger.writeTCP("Hashsum does not match", LogLevel.Error);
+					String line = "Computed checksum:\n";
 					byte[] c = computeHashsum(filename, HashAlgorithm.SHA512);
 					for (byte b: c) {
-						System.err.print(String.format("%02X", b));
-						logger.writeTCP("Computed checksum:" + String.format("%02X", b), LogLevel.Info);
+						line += String.format("%02X", b);
 					}
-					System.err.println("");
-					System.err.println("Received checksum:");
+					line += "\nReceived checksum:\n";
 					for (byte b: hash512) {
-						System.err.print(String.format("%02X", b));
-						logger.writeTCP("Received checksum:" + String.format("%02X", b), LogLevel.Info);
+						line += String.format("%02X", b);
 					}
-					System.err.println("");
+					line += "\n";
+					logger.writeTCP(line, LogLevel.Info);
 					throw new InternalError();
 				}
 			} else {
@@ -196,7 +191,6 @@ public class ClientManagementTCP implements Runnable {
 			logger.writeTCP(e, LogLevel.Error);
 			throw new ProtocolError();
 		} catch (SocketClosed e){
-			System.err.println("listDirectory : SocketClosed");
 			logger.writeTCP("listDirectory : SocketClosed", LogLevel.Error);
 			throw new ProtocolError();
 		} catch (NotATracker e) {
@@ -214,12 +208,37 @@ public class ClientManagementTCP implements Runnable {
 			MessageDigest md = MessageDigest.getInstance(HashAlgorithm.SHA512.getName());
 			return md.digest(Files.readAllBytes(Paths.get(baseDirectory + filename)));
 		} catch (NoSuchAlgorithmException e) {
-			System.out.println("Error: " + h.getName() + " not supported");
-			logger.writeTCP("Error: " + h.getName() + " not supported", LogLevel.Error);
+			logger.writeTCP(h.getName() + " not supported", LogLevel.Error);
 		} catch (IOException e) {
-			System.out.println("Error: cannot read " + filename);
-			logger.writeTCP("Error: cannot read " + filename, LogLevel.Error);
+			logger.writeTCP("cannot read " + filename, LogLevel.Error);
 		}
 		return new byte[0];
 	}
+
+	/** Initialize hostList from tracker
+	 * @throws	ProtocolError
+	 * @throws	InternalError
+	 */
+	private void initHostList() throws ProtocolError, InternalError {
+		ProtocolP2PPacketTCP d = new ProtocolP2PPacketTCP((Payload) new DiscoverRequest(null));
+		try {
+			d.sendRequest((Object)tracker.getTCPSocket());
+			Payload p = d.receiveResponse().getPayload();
+			assert p instanceof DiscoverResponse : "This payload must be instance of Filelist";
+			if (!(p instanceof DiscoverResponse)) {
+				throw new InternalError();
+			} else {
+				hostList = ((DiscoverResponse)p).getHostList();
+			}
+		} catch (SocketClosed e){
+			logger.writeTCP("listDirectory : SocketClosed", LogLevel.Error);
+			throw new ProtocolError();
+		} catch (NotATracker e) {
+			logger.writeTCP(e, LogLevel.Error);
+			throw new ProtocolError();
+		} catch (Exception e) {
+			logger.writeTCP(e, LogLevel.Error);
+			throw new ProtocolError();
+		}
+	}
 }

src/clientP2P/ClientManagementUDP.java

@@ -26,6 +26,8 @@ import protocolP2P.Payload;
 import protocolP2P.RequestResponseCode;
 import protocolP2P.FileList;
 import protocolP2P.HashAlgorithm;
+import protocolP2P.DiscoverRequest;
+import protocolP2P.DiscoverResponse;
 import tools.HostItem;
 import tools.Logger;
 import tools.LogLevel;
@@ -41,26 +43,36 @@ public class ClientManagementUDP implements Runnable {
 	private String baseDirectory;
 	private String partsSubdir;
 	private List<HostItem> hostList;
+	private HostItem tracker;
 	private Logger logger;
+	private Scanner scanner;
 
-	/** Constructor for UDP implementation, with baseDirectory and UDPPort parameters.
+	/** Constructor for UDP implementation, with baseDirectory, tracker, partsSubdir, logger and scanner parameters.
 	 * @param baseDirectory	the root directory where files are stored
-	 * @param host	hostname of the server
-	 * @param UDPPort	the server will listen on this port
+	 * @param tracker	tracker HostItem
+	 * @param partsSubdir	subdirectory to store file parts
+	 * @param logger	Loggger
+	 * @param scanner	Scanner used to read input
 	 */
-	public ClientManagementUDP(String baseDirectory, List<HostItem> hostList, String partsSubdir, Logger logger) {
+	public ClientManagementUDP(String baseDirectory, HostItem tracker, String partsSubdir, Logger logger, Scanner scanner) {
+		this.scanner = scanner;
 		this.baseDirectory = baseDirectory;
-		this.hostList = hostList;
+		this.tracker = tracker;
 		this.partsSubdir = partsSubdir;
 		this.logger = logger;
+		try {
+			initHostList();
+		} catch (InternalError e) {
+			System.exit(-1);
+		} catch (ProtocolError e) {
+			System.exit(-2);
+		}
 	}
 
 	/** Implementation of Runnable
 	 */
 	public void run() {
 		try {
-			System.out.println("Enter all servers: type \"stop\" when finished");
-			Scanner scanner = new Scanner(System.in);
 			String[] list = listDirectory();
 			System.out.println("Files present on the server:");
 			for(String listItem: list) {
@@ -68,7 +80,6 @@ public class ClientManagementUDP implements Runnable {
 			}
 			System.out.println("Name of the file to download:");
 			String f = scanner.nextLine();
-			scanner.close();
 			download(f);
 			System.out.println("File " + f + " sucessfully downloaded");
 			logger.writeUDP("File " + f + " sucessfully downloaded", LogLevel.Info);
@@ -217,4 +228,28 @@ public class ClientManagementUDP implements Runnable {
 		}
 		return new byte[0];
 	}
+
+	/** Initialize hostList from tracker
+	 * @throws	ProtocolError
+	 * @throws	InternalError
+	 */
+	private void initHostList() throws ProtocolError, InternalError {
+		ProtocolP2PPacketUDP d = new ProtocolP2PPacketUDP((Payload) new DiscoverRequest(null));
+		try {
+			d.sendRequest((Object)tracker.getUDPSocket());
+			Payload p = d.receiveResponse().getPayload();
+			assert p instanceof DiscoverResponse : "This payload must be instance of Filelist";
+			if (!(p instanceof DiscoverResponse)) {
+				throw new InternalError();
+			} else {
+				hostList = ((DiscoverResponse)p).getHostList();
+			}
+		} catch (NotATracker e) {
+			logger.writeUDP(e, LogLevel.Error);
+			throw new ProtocolError();
+		} catch (Exception e) {
+			logger.writeUDP(e, LogLevel.Error);
+			throw new ProtocolError();
+		}
+	}
 }

src/clientP2P/ClientP2P.java

@@ -10,7 +10,6 @@ import tools.Logger;
 import tools.LogLevel;
 import tools.Directories;
 import tools.HostItem;
-import tools.HostList;
 
 /** Client + Server implementation.
  * @author	Louis Royer
@@ -27,9 +26,9 @@ public class ClientP2P {
 	private String host;
 	private int port;
 	private Directories directories;
-	private List<HostItem> hostList;
 	private static final int defaultPort = 20000;
 	private HostItem tracker;
+	private Scanner scanner;
 
 
 	/** Initialize loggers if directories and logger are null,
@@ -47,6 +46,7 @@ public class ClientP2P {
 	 * @param portStr	String containing port for server listenning.
 	 */
 	public ClientP2P(String portStr) {
+		scanner = new Scanner(System.in);
 		tracker = new HostItem("localhost", 30000); // TODO : make it configurable
 		try{
 			port = Integer.valueOf(Integer.parseInt(portStr));
@@ -62,7 +62,7 @@ public class ClientP2P {
 		directories.createSubdir(parts);
 		host = "localhost";
 		System.out.println("Server will listen on port " + port + " and serve files from " + directories.getDataHomeDirectory() + subdir);
-		directories.askOpenDataHomeDirectory(subdir);
+		directories.askOpenDataHomeDirectory(subdir, scanner);
 		System.out.println("Please enter list of servers to use; first one will be used to ask list of files");
 	}
 
@@ -102,11 +102,9 @@ public class ClientP2P {
 			}
 
 			// initialize Host lists
-			c.hostList = HostList.getServList();
 			System.out.println("Client : Which transport protocol do you want to use? [TCP/udp]");
-			Scanner sc = new Scanner(System.in);
-			String transportchoosen = sc.nextLine();
-			sc.close();
+			c.scanner.hasNextLine();
+			String transportchoosen = c.scanner.nextLine();
 			Thread t;
 			switch(transportchoosen){
 				case "UDP":
@@ -114,7 +112,7 @@ public class ClientP2P {
 				case "upd": // alias typo
 				case "2" :
 					System.out.println("Starting with UDP");
-					ClientManagementUDP cmudp = new ClientManagementUDP(c.directories.getDataHomeDirectory(), c.hostList, c.directories.getDataHomeDirectory() + c.parts + "/", c.loggerClient);
+					ClientManagementUDP cmudp = new ClientManagementUDP(c.directories.getDataHomeDirectory(), c.tracker, c.directories.getDataHomeDirectory() + c.parts + "/", c.loggerClient, c.scanner);
 					t = new Thread(cmudp);
 					break;
 				case "TCP":
@@ -122,12 +120,16 @@ public class ClientP2P {
 				case "1":
 				default:
 					System.out.println("Starting with TCP");
-					ClientManagementTCP cmtcp = new ClientManagementTCP(c.directories.getDataHomeDirectory(), c.hostList, c.directories.getDataHomeDirectory() + c.parts + "/", c.loggerClient);
+					ClientManagementTCP cmtcp = new ClientManagementTCP(c.directories.getDataHomeDirectory(), c.tracker, c.directories.getDataHomeDirectory() + c.parts + "/", c.loggerClient, c.scanner);
 					t = new Thread(cmtcp);
 					break;
 				}
 			t.setName("client P2P-JAVA-PROJECT");
 			t.start();
+			try {
+				t.join();
+			} catch (InterruptedException e) {}
+			c.scanner.close();
 		}
 	}
 }

src/serverP2P/ServerP2P.java

@@ -4,6 +4,7 @@ import serverP2P.ServerManagementTCP;
 import tools.Directories;
 import tools.Logger;
 import tools.HostItem;
+import java.util.Scanner;
 
 /** Server only implementation
  * First argument of main method is port listened by the server, and is mandatory.
@@ -29,7 +30,9 @@ public class ServerP2P {
 		directories.createSubdir(subdir);
 		logger = new Logger(directories.getDataHomeDirectory() + "server.log");
 		System.out.println("Server will listen on port " + port + " and serve files from " + directories.getDataHomeDirectory() + subdir);
-		directories.askOpenDataHomeDirectory(subdir);
+		Scanner scanner = new Scanner(System.in);
+		directories.askOpenDataHomeDirectory(subdir, scanner);
+		scanner.close();
 	}
 
 	/** Main program entry point

src/tools/BytesArrayTools.java

@@ -231,11 +231,13 @@ public class BytesArrayTools {
 		try {
 			int i = start;
 			while(true) {
+				int j = i;
 				for(byte b: endStr.getBytes()) {
-					if (b != array[i]) {
+					if (b != array[j]) {
 						failed = true;
 						break;
 					}
+					j++;
 				}
 				if (failed) {
 					i++;
@@ -244,7 +246,7 @@ public class BytesArrayTools {
 					break;
 				}
 			}
-			return readString(array, start, i -1 - start);
+			return readString(array, start, i - start);
 		} catch(IndexOutOfBoundsException e) {
 			throw new InternalError();
 		}

src/tools/Directories.java

@@ -70,6 +70,7 @@ public class Directories {
 	}
 
 	/** Opens dataHomeDirectory if supported.
+	 * @param subdir	Subdir to open (optional)
 	 */
 	private void openDataHomeDirectory(String subdir) {
 		String d = dataHomeDirectory;
@@ -93,13 +94,13 @@ public class Directories {
 	}
 
 	/** Asks the user to choose opening dataHomeDirectory or not.
+	 * @param subdir	subdirectory to open (optional)
+	 * @param scanner	Scanner to use for reading input
 	 */
-	public void askOpenDataHomeDirectory(String subdir) {
+	public void askOpenDataHomeDirectory(String subdir, Scanner scanner) {
 		if (os.equals("Linux") || os.equals("Mac") || os.equals("Mac OS X")) {
 			System.out.println("Do you want to open this directory? (y/N)");
-			Scanner scanner = new Scanner(System.in);
 			String resp = scanner.nextLine();
-			scanner.close();
 			if (resp.equals("y") || resp.equals("Y")) {
 				System.out.println("Openning");
 				openDataHomeDirectory(subdir);

src/tools/HostItem.java

@@ -36,13 +36,13 @@ public class HostItem {
 			try {
 				tcpSocket = new Socket(InetAddress.getByName(hostname), port);
 			} catch (SocketException e) {
-				System.err.println("Error: No TCP socket available.");
+				System.err.println("getTCPSocket error: No TCP socket available.");
 				System.exit(-1);
 			} catch (UnknownHostException e) {
-				System.err.println("Error: Unknown host.");
+				System.err.println("getTCPSocket error: Unknown host (" + this + ").");
 				System.exit(-1);
 			} catch (IOException e) {
-				System.err.println("Error: Cannot create TCP socket");
+				System.err.println("getTCPSocket error: Cannot create TCP socket (" + this + ").");
 				System.exit(-1);
 			}
 		}
@@ -71,10 +71,10 @@ public class HostItem {
 				udpSocket = new DatagramSocket();
 				udpSocket.connect(InetAddress.getByName(hostname), port);
 			} catch (SocketException e) {
-				System.err.println("Error: No UDP socket available.");
+				System.err.println("getUDPSocket error: No UDP socket available." );
 				System.exit(-1);
 			} catch (UnknownHostException e) {
-				System.err.println("Error: Unknown host.");
+				System.err.println("getUDPSocket error: Unknown host (" + this + ").");
 				System.exit(-1);
 			}
 		}
@@ -135,7 +135,7 @@ public class HostItem {
 			try {
 				inetAddress = InetAddress.getByName(getHostname());
 			} catch (UnknownHostException e) {
-				System.err.println("Error: Unknown host.");
+				System.err.println("getInetAddress error: Unknown host (" + this + ").");
 				System.exit(-1);
 			}
 		}

src/tools/HostList.java

@@ -1,56 +0,0 @@
-package tools;
-
-import java.util.Scanner;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.InputMismatchException;
-import tools.HostItem;
-
-/** Helper to get the server list from the user
-* @author	Louis Royer
-* @author	Flavien Haas
-* @author	JS Auge
-* @version	1.0
-*/
-public class HostList {
-	/**
-	* Let the user enter all server and puts it in a list
-	* @return list of servers
-	*/
-	public static List<HostItem> getServList() {
-		List<HostItem> serverList = new ArrayList<HostItem>();
-		Scanner scanner = new Scanner(System.in);
-		String servName;
-		int port = 0;
-		do {
-			System.out.println("Enter hostname of next server: (or \"stop\" when finished, default: localhost).");
-			servName = scanner.nextLine();
-			if (servName.equals("")) {
-				servName = "localhost";
-			}
-			if (!servName.equals("stop")) {
-				boolean err = false;
-				do {
-					System.out.println("Enter port for this server");
-					try {
-						port = scanner.nextInt();
-						scanner.nextLine();
-						if (port > 65535 || port <= 0) {
-							err = true;
-							System.out.println("Port number must be in 1-65535 range. Try again.");
-						} else {
-							err = false;
-						}
-					} catch (InputMismatchException e) {
-						System.out.println("Invalid number. Try again.");
-						err = true;
-					}
-				} while (err);
-				serverList.add(new HostItem(servName, port));
-			}
-			
-		} while (!servName.equals("stop"));
-		scanner.close();
-		return serverList;
-	}
-}

src/tracker/Tracker.java

@@ -3,6 +3,7 @@ import tracker.TrackerManagementTCP;
 import tracker.TrackerManagementUDP;
 import tools.Directories;
 import tools.Logger;
+import java.util.Scanner;
 
 /** Tracker implementation
  * First argument of main method is port listened by the tracker, and is mandatory.
@@ -24,7 +25,9 @@ public class Tracker {
 		directories = new Directories("P2P_JAVA_PROJECT_TRACKER_" + port);
 		logger = new Logger(directories.getDataHomeDirectory() + "tracker.log");
 		System.out.println("Tracker will listen on port " + port + " and write logs into " + directories.getDataHomeDirectory());
-		directories.askOpenDataHomeDirectory(null);
+		Scanner scanner = new Scanner(System.in);
+		directories.askOpenDataHomeDirectory(null, scanner);
+		scanner.close();
 	}
 
 	/** Main program entry point

src/tracker/TrackerManagementTCP.java

@@ -20,8 +20,8 @@ import java.util.HashMap;
 import protocolP2P.DiscoverRequest;
 import protocolP2P.DiscoverResponse;
 import protocolP2P.FileList;
-import protocolP2P.HashRequest;
 import localException.InternalError;
+import remoteException.EmptyDirectory;
 import java.net.UnknownHostException;
 import java.net.InetAddress;
 import localException.SocketClosed;
@@ -204,6 +204,10 @@ public class TrackerManagementTCP implements Runnable {
 				handleListResponse((ProtocolP2PPacketTCP)pLReq.receiveResponse(), host);
 				logger.writeTCP("Received LIST RESPONSE from host " + pd.getHostItem(), LogLevel.Action);
 				host.closeTCPSocket();
+			} catch (EmptyDirectory e) {
+				logger.writeTCP("Empty Directory", LogLevel.Debug);
+				hostList.remove(host);
+				logger.writeTCP("Received EMPTY DIRECTORY from host " + pd.getHostItem() + ". Aborting.", LogLevel.Action);
 			} catch (Exception e) {
 				// remove from list because list request could not be send
 				hostList.remove(host);
@@ -245,7 +249,7 @@ public class TrackerManagementTCP implements Runnable {
 			if (!(p instanceof DiscoverRequest)) {
 				sendInternalError(pd);
 			} else {
-				String filename = ((HashRequest)p).getFilename();
+				String filename = ((DiscoverRequest)p).getFilename();
 				try {
 					pd.sendResponse((ProtocolP2PPacket)new ProtocolP2PPacketTCP((Payload)new DiscoverResponse(filename, fileList.getOrDefault(filename, hostList))));
 				} catch (Exception e) {

src/tracker/TrackerManagementUDP.java

@@ -19,7 +19,6 @@ import java.util.HashMap;
 import protocolP2P.DiscoverRequest;
 import protocolP2P.DiscoverResponse;
 import protocolP2P.FileList;
-import protocolP2P.HashRequest;
 import localException.InternalError;
 import remoteException.EmptyDirectory;
 import java.net.InetAddress;
@@ -201,7 +200,7 @@ public class TrackerManagementUDP implements Runnable {
 		if (!(p instanceof DiscoverRequest)) {
 			sendInternalError(pd);
 		} else {
-			String filename = ((HashRequest)p).getFilename();
+			String filename = ((DiscoverRequest)p).getFilename();
 			try {
 				pd.sendResponse((ProtocolP2PPacket)new ProtocolP2PPacketUDP((Payload)new DiscoverResponse(filename, fileList.getOrDefault(filename, hostList))));
 			} catch (Exception e) {