src/clientP2P/ClientDownload.java

@@ -335,7 +335,7 @@ public abstract class ClientDownload extends ServeErrors implements Runnable {
 	protected void setSize() throws InternalError {
 		ProtocolP2PPacket<?> d = createProtocolP2PPacket(new SizeRequest(filename));
 		try {
-			d.sendRequest(getHostItemSocket(hostList.get(0)));
+			d.sendRequest(getHostItemSocket(tracker));
 			try {
 				Payload p = d.receiveResponse().getPayload();
 				assert p instanceof SizeResponse : "This payload must be instance of SizeResponse";
@@ -449,6 +449,8 @@ public abstract class ClientDownload extends ServeErrors implements Runnable {
 
 		// get size
 		setSize();
+		// close tracker socket
+		closeHostItemSocket(tracker);
 
 		// get hashsum from 1st server in list
 		hash512 = getHashSum512(hostList.get(0));

src/clientP2P/ClientInterfaceCLI.java

@@ -32,6 +32,7 @@ import java.net.SocketException;
  */
 public class ClientInterfaceCLI extends ClientInterface {
 	private Scanner scanner;
+	private String[] list;
 
 	/** Constructor with clientManagement, logger and scanner.
 	 * @param clientManagement	ClientManagement used
@@ -53,7 +54,9 @@ public class ClientInterfaceCLI extends ClientInterface {
 				SearchFile searchEngine = new SearchFile();
 				int optionSearch = 0;
 				String searchInput = "";
-				String[] list = clientManagement.listDirectory();
+				if (!initFileList()) {
+					break;
+				}
 				String[] resultArray = {};
 				boolean searchChoice = false;
 				while (!searchChoice) {
@@ -65,7 +68,7 @@ public class ClientInterfaceCLI extends ClientInterface {
 						optionSearch = Integer.parseInt(scanner.nextLine());
 					} catch (NumberFormatException e) {
 						System.out.println("Wrong input, try again");
-						break;
+						continue;
 					}
 					switch(optionSearch) {
 						case 1:
@@ -146,8 +149,6 @@ public class ClientInterfaceCLI extends ClientInterface {
 						writeLog("File " + f + " unsucessfully downloaded, wrong number", LogLevel.Error);
 					}
 				}
-			} catch (EmptyDirectory e) {
-				writeLog("Server has no file in directory", LogLevel.Error);
 			} catch (InternalError e) {
 				writeLog("Client internal error", LogLevel.Error);
 			} catch (UnknownHostException e) {
@@ -205,4 +206,33 @@ public class ClientInterfaceCLI extends ClientInterface {
 		}
 		return !stop;
 	}
+
+	/** Initialize file list
+	 * @return true if successfully initialized
+	 */
+	private boolean initFileList() {
+		boolean contacted = false;
+		boolean firstLoop = true;
+		boolean stop = false;
+		while (!contacted && !stop) {
+			try {
+				if (!firstLoop) {
+					String tryAgain = scanner.nextLine();
+					if (tryAgain.equals("n") || tryAgain.equals("N")) {
+						stop = true;
+					}
+				}
+				firstLoop = false;
+				list = clientManagement.listDirectory();
+				contacted = true;
+			} catch(EmptyDirectory e) {
+				writeLog("Tracker has no file registered. Try again [Y/n]?", LogLevel.Error);
+			} catch(InternalError e) {
+				writeLog("Internal error while fetching tracked files. Try again [Y/n]?", LogLevel.Error);
+			} catch(Exception e) {
+				writeLog("Cannot contact tracker. Try again [Y/n]?", LogLevel.Error);
+			}
+		}
+		return !stop;
+	}
 }

src/tracker/TrackerManagement.java

@@ -18,6 +18,8 @@ import protocolP2P.RequestResponseCode;
 import protocolP2P.RatioRequest;
 import protocolP2P.RatioResponse;
 import protocolP2P.UpdateRatio;
+import protocolP2P.SizeRequest;
+import protocolP2P.SizeResponse;
 import localException.InternalError;
 import remoteException.EmptyDirectory;
 import exception.LocalException;
@@ -37,6 +39,7 @@ public abstract class TrackerManagement extends ServeErrors implements Runnable
 	protected Map<HostItem, Long> ratioUp = new HashMap<>();
 	protected Map<HostItem, Long> ratioDown = new HashMap<>();
 	protected Map<String, List<HostItem>> fileList = new HashMap<>();
+	protected Map<String, Long> fileSize = new HashMap<>();
 	protected volatile boolean stop;
 	protected AtomicBoolean writeLock;
 	protected AtomicInteger readLock;
@@ -154,6 +157,22 @@ public abstract class TrackerManagement extends ServeErrors implements Runnable
 							List<HostItem> emptyH = new ArrayList<>();
 							emptyH.add(host);
 							fileList.put(file, emptyH);
+							try {
+								writeLog("Registering new file : " + file + ". Sending size request ", LogLevel.Debug);
+								ProtocolP2PPacket<?> pSReq = createProtocolP2PPacket(new SizeRequest(file));
+								pSReq.sendRequest(getHostItemSocket(host));
+								SizeResponse pSResp = (SizeResponse)pSReq.receiveResponse().getPayload();
+								if (!pSResp.getFilename().equals(file)) {
+									writeLog("Wrong filename for size response of " + file, LogLevel.Debug);
+									throw new InternalError();
+								} else {
+									writeLog("Registering size of file " + file, LogLevel.Debug);
+									fileSize.put(file, Long.valueOf(pSResp.getTotalSize()));
+								}
+							} catch (Exception e) {
+								writeLog("Error while asking for size of " + file, LogLevel.Error);
+								fileList.remove(file);
+							}
 						} 
 					}
 					writeLock.getAndSet(false);
@@ -192,6 +211,7 @@ public abstract class TrackerManagement extends ServeErrors implements Runnable
 					fileList.get(f).remove(host);
 					if(fileList.get(f).isEmpty()) {
 						fileList.remove(f);
+						fileSize.remove(f);
 					}
 				}
 				writeLock.getAndSet(false);
@@ -370,6 +390,45 @@ public abstract class TrackerManagement extends ServeErrors implements Runnable
 		}
 	}
 
+	/** Handle Size request
+	 * @param pd	Received request
+	 * @throws	InternalError
+	 */
+	protected < T extends ProtocolP2PPacket<?> > void handleSizeRequest(T pd) throws InternalError {
+			Payload p = pd.getPayload();
+			assert p instanceof SizeRequest : "payload must be an instance of SizeRequest";
+			if (!(p instanceof SizeRequest)) {
+				throw new InternalError();
+			}
+			String f = ((SizeRequest)p).getFilename();
+			try {
+				Long s;
+				synchronized (this) {
+					while(writeLock.get()) {
+						this.wait();
+					}
+					readLock.incrementAndGet();
+					s = fileSize.get(f);
+					readLock.decrementAndGet();
+					this.notify();
+				}
+				if (s == null) {
+					writeLog("Sending NOT FOUND for file " + f + " to " + pd.getHostItem(), LogLevel.Action);
+					sendNotFound(pd);
+				} else if (s.equals(Long.valueOf(0))) {
+					writeLog("Sending EMPTY FILE for file " + f + " to " + pd.getHostItem(), LogLevel.Action);
+					sendEmptyFile(pd);
+				} else {
+					writeLog("Sending SIZE RESPONSE for file " + f + " to " + pd.getHostItem(), LogLevel.Action);
+					pd.sendResponse(createProtocolP2PPacket(new SizeResponse(f, s.longValue())));
+				}
+			} catch (InterruptedException e) {
+				throw new InternalError();
+			} catch (Exception e) {
+				writeLog(e, LogLevel.Error);
+			}
+	}
+
 
 	/** Handle requests
 	 * @throws	LocalException
@@ -409,6 +468,10 @@ public abstract class TrackerManagement extends ServeErrors implements Runnable
 				writeLog("Received UPDATE RATIO from host " + pd.getHostItem(), LogLevel.Action);
 				handleUpdateRatio(pd);
 				break;
+			case SIZE_REQUEST:
+				writeLog("Received SIZE REQUEST from host " + pd.getHostItem(), LogLevel.Action);
+				handleSizeRequest(pd);
+				break;
 			default:
 				writeLog("Received grabbage from host " + pd.getHostItem(), LogLevel.Action);
 				sendInternalError(pd);