Persistent content storage now working perfectly!!!

src/kademlia/core/Configuration.java

@@ -47,4 +47,9 @@ public class Configuration
      * Number of times a node can be marked as stale before it is actually removed.
      * */
     public static int STALE = 1;
+    
+    /**
+     * Local Storage location - Relative to the user's home folder (Cross-Platform)
+     */
+    public static String localFolder = "kademlia";
 }

src/kademlia/core/KadServer.java

@@ -96,11 +96,15 @@ public class KadServer
         /* Generate a random communication ID */
         int comm = new Integer(new Random().nextInt());
 
+        /* If we have a receiver */
+        if (recv != null)
+        {
             /* Setup the receiver to handle message response */
             receivers.put(comm, recv);
             TimerTask task = new TimeoutTask(comm, recv);
             timer.schedule(task, Configuration.RESPONSE_TIMEOUT);
             tasks.put(comm, task);
+        }
 
         /* Send the message */
         sendMessage(to, msg, comm);

src/kademlia/core/Kademlia.java

@@ -4,6 +4,7 @@ import java.io.IOException;
 import java.net.InetAddress;
 import java.util.Timer;
 import java.util.TimerTask;
+import kademlia.dht.DHT;
 import kademlia.dht.KadContent;
 import kademlia.exceptions.RoutingException;
 import kademlia.message.MessageFactory;
@@ -33,6 +34,7 @@ public class Kademlia
     /* Objects to be used */
     private final Node localNode;
     private final KadServer server;
+    private final DHT dht;
     private final Timer timer;
 
     /* Factories */
@@ -56,7 +58,8 @@ public class Kademlia
     {
         this.ownerId = ownerId;
         this.localNode = new Node(defaultId, InetAddress.getLocalHost(), udpPort);
-        this.messageFactory = new MessageFactory(localNode);
+        this.dht = new DHT();
+        this.messageFactory = new MessageFactory(localNode, this.dht);
         this.server = new KadServer(udpPort, this.messageFactory, this.localNode);
         this.timer = new Timer(true);
 

src/kademlia/dht/DHT.java

@@ -0,0 +1,66 @@
+package kademlia.dht;
+
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import kademlia.core.Configuration;
+import kademlia.serializer.JsonSerializer;
+
+/**
+ * The main Distributed Hash Table class that manages the entire DHT
+ *
+ * @author Joshua Kissoon
+ * @since 20140226
+ */
+public class DHT
+{
+
+    private final StorageEntryManager entriesManager;
+
+    
+    {
+        entriesManager = new StorageEntryManager();
+    }
+
+    /**
+     * Handle storing content locally
+     *
+     * @param content The DHT content to store
+     *
+     * @throws java.io.IOException
+     */
+    public void store(KadContent content) throws IOException
+    {
+        /* Keep track of this content in the entries manager */
+        this.entriesManager.put(new StorageEntry(content));
+
+        /**
+         * Now we store the content locally in a file
+         * Each content is stored in a folder named after the first 10 characters of the NodeId
+         *
+         * The name of the file containing the content is the hash of this content
+         */
+        String storagePath = System.getProperty("user.home") + File.separator + Configuration.localFolder;
+        File mainStorageFolder = new File(storagePath);
+
+        /* Create the folder if it doesn't exist */
+        if (!mainStorageFolder.isDirectory())
+        {
+            mainStorageFolder.mkdir();
+        }
+
+        /* Check if a folder after the first 10 characters of Hex(nodeId) exist, if not, create it */
+        String folderName = content.getKey().hexRepresentation().substring(0, 20);
+        File contentStorageFolder = new File(mainStorageFolder + File.separator + folderName);
+        if (!contentStorageFolder.isDirectory())
+        {
+            contentStorageFolder.mkdir();
+        }
+
+        /* Write the content to a file and store it in the folder */
+        File contentFile = new File(String.valueOf(content.hashCode()) + ".kct");
+        DataOutputStream dout = new DataOutputStream(new FileOutputStream(contentStorageFolder + File.separator + contentFile));
+        new JsonSerializer().write(content, dout);
+    }
+}

src/kademlia/dht/StorageEntry.java

@@ -0,0 +1,52 @@
+package kademlia.dht;
+
+import java.util.Objects;
+import kademlia.node.NodeId;
+
+/**
+ * Keeps track of data for a Content stored in the DHT
+ * Used by the StorageEntryManager class
+ *
+ * @author Joshua Kissoon
+ * @since 20140226
+ */
+public class StorageEntry
+{
+
+    private final NodeId key;
+    private final String ownerId;
+    private final String type;
+
+    public StorageEntry(KadContent content)
+    {
+        this.key = content.getKey();
+        this.ownerId = content.getOwnerId();
+        this.type = content.getType();
+    }
+
+    public NodeId getKey()
+    {
+        return this.key;
+    }
+
+    @Override
+    public boolean equals(Object o)
+    {
+        if (o instanceof StorageEntry)
+        {
+            return this.hashCode() == o.hashCode();
+        }
+
+        return false;
+    }
+
+    @Override
+    public int hashCode()
+    {
+        int hash = 3;
+        hash = 23 * hash + Objects.hashCode(this.key);
+        hash = 23 * hash + Objects.hashCode(this.ownerId);
+        hash = 23 * hash + Objects.hashCode(this.type);
+        return hash;
+    }
+}

src/kademlia/dht/StorageEntryManager.java

@@ -0,0 +1,68 @@
+package kademlia.dht;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import kademlia.node.NodeId;
+
+/**
+ * It would be infeasible to keep all content in memory to be send when requested
+ * Instead we store content into files
+ * We use this Class to keep track of all content stored
+ *
+ * @author Joshua Kissoon
+ * @since 20140226
+ */
+public class StorageEntryManager
+{
+
+    private final HashMap<NodeId, ArrayList<StorageEntry>> entries;
+
+    
+    {
+        entries = new HashMap<>();
+    }
+
+    /**
+     * Add a new entry to our storage
+     *
+     * @param entry
+     */
+    public void put(StorageEntry entry)
+    {
+        if (!this.entries.containsKey(entry.getKey()))
+        {
+            this.entries.put(entry.getKey(), new ArrayList<StorageEntry>());
+        }
+        
+        this.entries.get(entry.getKey()).add(entry);
+    }
+
+    /**
+     * Checks if our DHT has a Content for the given criteria
+     *
+     * @todo Add searching for content by type and ownerID
+     *
+     * @param key
+     *
+     * @return boolean
+     */
+    public boolean contains(NodeId key)
+    {
+        return this.entries.containsKey(key);
+    }
+
+    /**
+     * Checks if our DHT has a Content for the given criteria
+     *
+     * @todo Add finding for content by type and ownerID
+     *
+     * @param key
+     *
+     * @return List of content for the specific search parameters
+     */
+    public ArrayList<StorageEntry> get(NodeId key)
+    {
+        return this.entries.get(key);
+    }
+
+}

src/kademlia/message/MessageFactory.java

@@ -3,6 +3,7 @@ package kademlia.message;
 import java.io.DataInputStream;
 import java.io.IOException;
 import kademlia.core.KadServer;
+import kademlia.dht.DHT;
 import kademlia.node.Node;
 import kademlia.operation.Receiver;
 
@@ -16,10 +17,12 @@ public class MessageFactory
 {
 
     private final Node localNode;
+    private final DHT dht;
 
-    public MessageFactory(Node local)
+    public MessageFactory(Node local, DHT dht)
     {
         this.localNode = local;
+        this.dht = dht;
     }
 
     public Message createMessage(byte code, DataInputStream in) throws IOException
@@ -57,7 +60,7 @@ public class MessageFactory
             case NodeLookupMessage.CODE:
                 return new NodeLookupReceiver(server, this.localNode);
             case StoreContentMessage.CODE:
-                return new StoreContentReceiver(server, this.localNode);
+                return new StoreContentReceiver(server, this.localNode, this.dht);
         }
     }
 }

src/kademlia/message/StoreContentMessage.java

@@ -48,7 +48,7 @@ public class StoreContentMessage implements Message
     }
 
     @Override
-    public void fromStream(DataInputStream in) throws IOException
+    public final void fromStream(DataInputStream in) throws IOException
     {
         this.origin = new Node(in);
         try
@@ -61,12 +61,23 @@ public class StoreContentMessage implements Message
         }
     }
 
+    public Node getOrigin()
+    {
+        return this.origin;
+    }
+
+    public KadContent getContent()
+    {
+        return this.content;
+    }
+
     @Override
     public byte code()
     {
         return CODE;
     }
 
+    @Override
     public String toString()
     {
         return "StoreMessage[origin=" + origin + ",content=" + content + "]";

src/kademlia/message/StoreContentReceiver.java

@@ -1,6 +1,8 @@
 package kademlia.message;
 
+import java.io.IOException;
 import kademlia.core.KadServer;
+import kademlia.dht.DHT;
 import kademlia.node.Node;
 import kademlia.operation.Receiver;
 
@@ -15,20 +17,37 @@ public class StoreContentReceiver implements Receiver
 
     private final KadServer server;
     private final Node localNode;
+    private final DHT dht;
 
-    public StoreContentReceiver(KadServer server, Node localNode)
+    public StoreContentReceiver(KadServer server, Node localNode, DHT dht)
     {
         this.server = server;
         this.localNode = localNode;
+        this.dht = dht;
     }
 
     @Override
     public void receive(Message incoming, int comm)
     {
-        /* @todo - Insert the message sender into this node's routing table */
+        /* It's a StoreContentMessage we're receiving */
         StoreContentMessage msg = (StoreContentMessage) incoming;
+
+        /* Insert the message sender into this node's routing table */
+        this.localNode.getRoutingTable().insert(msg.getOrigin());
+
         System.out.println(this.localNode + " - Received a store content message");
         System.out.println(msg);
+
+        try
+        {
+            /* Store this Content into the DHT */
+            this.dht.store(msg.getContent());
+        }
+        catch (IOException e)
+        {
+            System.err.println("Unable to store received content; Message: " + e.getMessage());
+        }
+
     }
 
     @Override

src/kademlia/node/NodeId.java

@@ -5,9 +5,7 @@
  */
 package kademlia.node;
 
-import java.io.DataInput;
 import java.io.DataInputStream;
-import java.io.DataOutput;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.math.BigInteger;
@@ -25,8 +23,6 @@ public class NodeId implements Streamable
      * Construct the NodeId from some string
      *
      * @param data The user generated key string
-     *
-     * @todo Throw an exception if the key is too short or too long
      */
     public NodeId(String data)
     {
@@ -202,15 +198,17 @@ public class NodeId implements Streamable
         this.keyBytes = input;
     }
 
+    public String hexRepresentation()
+    {
+        /* Returns the hex format of this NodeId */
+        BigInteger bi = new BigInteger(1, this.keyBytes);
+        return String.format("%0" + (this.keyBytes.length << 1) + "X", bi);
+    }
+
     @Override
     public String toString()
     {
-        // StringBuilder sb = new StringBuilder("NodeId: ");
-        BigInteger bi = new BigInteger(1, this.keyBytes);
-        return String.format("%0" + (this.keyBytes.length << 1) + "X", bi);
-        //sb.append(Hex.encodeBase64URLSafeString(this.keyBytes));
-
-        //return sb.toString();
+        return this.hexRepresentation();
     }
 
 }