Write test for assignment example

src/main/java/Main.java

@@ -67,7 +67,11 @@ public static void main(String[] args) {
                                                                "<PORT OF EXISTING PEER IN NETWORK> " +
                                                                "<KEY (INTEGER)> <VALUE (STRING)> to use this command.");
 
-                        PutClient.put(args);
+                        PutClient.put( args[1]
+                                     , Common.parseInteger(args[2])
+                                     , Common.parseInteger(args[3])
+                                     , args[4]
+                                     );
                         break;
                     case GET:
                         if (args.length != 5)
@@ -77,7 +81,11 @@ public static void main(String[] args) {
                                                                "<OWN PORT TO BIND TO> <KEY (INTEGER)>) to use" +
                                                                "this command.");
 
-                        GetClient.get(args);
+                        GetClient.get( args[1]
+                                     , Common.parseInteger(args[2])
+                                     , Common.parseInteger(args[3])
+                                     , Common.parseInteger(args[4])
+                                     );
                         break;
                 }
             } catch (IllegalArgumentException e) {

src/main/java/Peer.java

@@ -41,21 +41,32 @@ public class Peer {
     // Key-value pairs that this peer is responsible for storing
     private final Map<Integer, String> storedData;
 
+    // Thread that is listening
+    private Listener listener;
+
     Peer(PeerAddress ownAddress) {
         this.ownAddress = ownAddress;
         this.incomingMessageHandler = new IncomingMessageHandler(this);
         this.storedData = new HashMap<>();
 
-        System.out.println(String.format("Peer started on %s:%d (ID: %s)",
-                                         this.ownAddress.getIp(),
-                                         this.ownAddress.getPort(),
-                                         this.ownAddress.getHashId()));
+        System.out.println(String.format("Peer started on %s", this.ownAddress));
+
+        this.listener = new Listener(this);
+        this.listener.start(); // Starts to listen for incoming connections
+    }
+
+    public void stop() {
+        this.listener.abort();
+    }
 
-        new Listener(this).start(); // Starts to listen for incoming connections
+    @Override
+    public String toString() {
+        return this.ownAddress.toString();
     }
 
     private class Listener extends Thread {
         private final Peer peer; // Reference to peer that initialized this thread
+        private ServerSocket socket; // Reference to listening socket (needed to kill Listener via "abort")
 
         private Listener(Peer peer) {
             this.peer = peer;
@@ -67,15 +78,28 @@ private Listener(Peer peer) {
          */
         @Override
         public void run() {
-            try (ServerSocket socket = new ServerSocket(this.peer.ownAddress.getPort())) {
+            try {
+                this.socket = new ServerSocket(this.peer.ownAddress.getPort());
                 System.out.println("Listening...");
 
                 while (true) {
                     Socket clientSocket = socket.accept();
                     new ClientHandler(clientSocket, this.peer).start();
                 }
             } catch (IOException e) {
-                e.printStackTrace();
+                System.out.println( String.format("Peer %s exited.", this.peer)
+                                  + " Exception: \"" + e.getMessage() + "\""
+                                  );
+            } finally {
+                this.abort();
+            }
+        }
+
+        void abort() {
+            try {
+                this.socket.close();
+            } catch (IOException e) {
+                // Ignore exception from closing socket
             }
         }
     }
@@ -191,11 +215,9 @@ public void sendMessageToPeer(PeerAddress destinationPeer, Message message) thro
                 outputStream.writeObject(message);
             } else {
                 Logging.debugLog(String.format("Failed to send message (type: %s) to peer " +
-                                               "(IP: %s, port: %d, ID: %s)",
+                                               "%s",
                                                message.getClass().toString(),
-                                               destinationPeer.getIp(),
-                                               destinationPeer.getPort(),
-                                               destinationPeer.getHashId()), true);
+                                               destinationPeer), true);
             }
         } catch (IOException e) {
             e.printStackTrace();
@@ -217,10 +239,7 @@ public PeerAddress getSuccessor() {
     public void setSuccessor(PeerAddress newSuccessor) {
         this.successor = newSuccessor;
 
-        Logging.debugLog(String.format("Updated successor to %s:%d (ID: %s)",
-                                       newSuccessor.getIp(),
-                                       newSuccessor.getPort(),
-                                       newSuccessor.getHashId()),
+        Logging.debugLog(String.format("Updated successor to %s", newSuccessor),
                          false);
     }
 
@@ -231,10 +250,7 @@ public PeerAddress getNextSuccessor() {
     public void setNextSuccessor(PeerAddress newNextSuccessor) {
         this.nextSuccessor = newNextSuccessor;
 
-        Logging.debugLog(String.format("Updated next successor to %s:%d (ID: %s)",
-                                       newNextSuccessor.getIp(),
-                                       newNextSuccessor.getPort(),
-                                       newNextSuccessor.getHashId()),
+        Logging.debugLog(String.format("Updated next successor to %s", newNextSuccessor),
                          false);
     }
 

src/main/java/PeerAddress.java

@@ -30,4 +30,13 @@ public int getPort() {
     public BigInteger getHashId() {
         return hashId;
     }
+
+    @Override
+    public String toString() {
+        return String.format("%s:%d (ID: %s)",
+                this.getIp(),
+                this.getPort(),
+                this.getHashId()
+        );
+    }
 }

src/main/java/clients/GetClient.java

@@ -18,14 +18,8 @@ public class GetClient {
      * Sends a 'GetMessage' to the peer which address is taken as argument to program.
      * Afterwards listen on the port - also taken as argument to program - for any response.
      */
-    public static void get(String[] programArguments) {
-        String peerAddress = programArguments[1];
-        int peerPort = Common.parseInteger(programArguments[2]);
-
+    public static PutMessage get(String peerAddress, int peerPort, int ownPort, int key) {
         String ownIp = Common.getOwnIp();
-        int ownPort = Common.parseInteger(programArguments[3]);
-
-        int key = Common.parseInteger(programArguments[4]);
 
         try {
             Socket requestSocket = new Socket(peerAddress, peerPort); // Socket for sending 'GetMessage' to peer
@@ -37,6 +31,8 @@ public static void get(String[] programArguments) {
             ServerSocket listenSocket = new ServerSocket(ownPort); // Socket to listen for response to 'GetMessage'
             // Waits for incoming connection with response
             Socket responseSocket = listenSocket.accept();
+            // Stop listening
+            listenSocket.close();
             ObjectInputStream responseInputStream = new ObjectInputStream(responseSocket.getInputStream());
 
             Object input = responseInputStream.readObject();
@@ -47,16 +43,18 @@ public static void get(String[] programArguments) {
 
                 if (message.getValue() == null) {
                     System.out.println(String.format("Value not found. Key: %d", message.getKey()));
-                    return;
+                } else {
+                    System.out.println(String.format("Key: %d, value: %s", message.getKey(), message.getValue()));
                 }
 
-                System.out.println(String.format("Key: %d, value: %s", message.getKey(), message.getValue()));
+                return message;
             }
         } catch (SocketException e) {
             Logging.debugLog("Could not establish connection to given peer. Full error details: " + e.getMessage(),
                              true);
         } catch (IOException | ClassNotFoundException e) {
             e.printStackTrace();
         }
+        return null;
     }
 }

src/main/java/clients/PutClient.java

@@ -14,13 +14,7 @@ public class PutClient {
      * Sends a 'PutMessage' to the peer which address is taken as argument to program.
      * Terminates the process afterwards.
      */
-    public static void put(String[] programArguments) {
-        String peerAddress = programArguments[1];
-        int peerPort = Common.parseInteger(programArguments[2]);
-
-        int key = Common.parseInteger(programArguments[3]);
-        String value = programArguments[4];
-
+    public static void put(String peerAddress, int peerPort, int key, String value) {
         try (
              Socket socket = new Socket(peerAddress, peerPort);
              ObjectOutputStream outputStream = new ObjectOutputStream(socket.getOutputStream())

src/main/java/messages/PutMessage.java

@@ -3,6 +3,7 @@
 import main.java.utilities.SHA1Hasher;
 
 import java.math.BigInteger;
+import java.util.Objects;
 
 /**
  * Message containing the data that has to be stored in the network
@@ -29,4 +30,23 @@ public BigInteger getKeyHashId() {
     public String getValue() {
         return this.value;
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        PutMessage that = (PutMessage) o;
+        return key == that.key &&
+                Objects.equals(value, that.value);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(key, value);
+    }
+
+    @Override
+    public String toString() {
+        return "Put(" + key + ", " + value + ')';
+    }
 }

test/main/java/MainTest.java

@@ -0,0 +1,81 @@
+package main.java;
+
+import main.java.clients.GetClient;
+import main.java.clients.PutClient;
+import main.java.messages.PutMessage;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class MainTest {
+    private static String OWN_IP = "localhost";
+
+    /*
+        https://learnit.itu.dk/mod/assign/view.php?id=92747
+
+        Node starts at 1025.
+        Node starts at 1026, knowing 1025.
+        Client PUT(1, A) to 1025.
+        Client at 2048 sends GET(1, 2048) to 1025; eventually receives PUT(1, A) at 2048 from someone.
+        Client at 2049 sends GET(1, 2049) to 1026; eventually receives PUT(1, A) at 2049 from someone.
+        Client at 2049 sends GET(2, 2049) to 1025; eventually receives message saying the resource is not found.
+        Node C starts at 1027, knowing 1026.
+        Client at 2048 sends GET(1, 2048) to 1027; eventually receives PUT(1, A) at 2048 from someone.
+        PUT(2, B) to 1025.
+        Node 1025 crashes.
+        Client at 2048 sends GET(2, 2048) to 1026, eventually receives PUT(2, B) from someone.
+    */
+    @Test
+    void main() {
+        // Node starts at 1025
+        Peer peer1025 = new Peer(new PeerAddress(OWN_IP, 1025));
+        WAIT(1000);
+
+        // Node starts at 1026, knowing 1025
+        Peer peer1026 = new Peer(new PeerAddress(OWN_IP, 1026));
+        peer1026.joinNetworkByExistingPeer(new PeerAddress(OWN_IP, 1025));
+        WAIT(1000);
+
+        // Client PUT(1, A) to 1025
+        PutClient.put(OWN_IP, 1025, 1, "A");
+
+        // Client at 2048 sends GET(1, 2048) to 1025; eventually receives PUT(1, A) at 2048 from someone
+        assertEquals(new PutMessage(1, "A"), GET(1, 2048, 1025));
+
+        // Client at 2049 sends GET(1, 2049) to 1026; eventually receives PUT(1, A) at 2049 from someone.
+        assertEquals(new PutMessage(1, "A"), GET(1, 2049, 1026));
+
+        // Client at 2049 sends GET(2, 2049) to 1025; eventually receives message saying the resource is not found.
+        assertEquals(new PutMessage(2, null), GET(2, 2049, 1025));
+
+        // Node C starts at 1027, knowing 1026.
+        Peer peer1027 = new Peer(new PeerAddress(OWN_IP, 1027));
+        peer1027.joinNetworkByExistingPeer(new PeerAddress(OWN_IP, 1026));
+        WAIT(1000);
+
+        // Client at 2048 sends GET(1, 2048) to 1027; eventually receives PUT(1, A) at 2048 from someone.
+        assertEquals(new PutMessage(1, "A"), GET(1, 2048, 1027));
+
+        // PUT(2, B) to 1025.
+        PutClient.put(OWN_IP, 1025, 2, "B");
+
+        // Node 1025 crashes.
+        peer1025.stop();
+        WAIT(1000);
+
+        // Client at 2048 sends GET(2, 2048) to 1026, eventually receives PUT(2, B) from someone.
+        assertEquals(new PutMessage(2, "B"), GET(2, 2048, 1026));
+    }
+
+    private static PutMessage GET(int key, int ownPort, int peerPort) {
+        return GetClient.get(OWN_IP, peerPort, ownPort, key);
+    }
+
+    private static void WAIT(int millis) {
+        try {
+            Thread.sleep(millis);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+}