Problem with serializing the DHT also, had to create a DHT specific Serializer class

src/kademlia/core/Kademlia.java

@@ -25,6 +25,7 @@ import kademlia.operation.Operation;
 import kademlia.operation.KadRefreshOperation;
 import kademlia.operation.StoreOperation;
 import kademlia.routing.RoutingTable;
+import kademlia.serializer.JsonDHTSerializer;
 import kademlia.serializer.JsonRoutingTableSerializer;
 import kademlia.serializer.JsonSerializer;
 
@@ -42,6 +43,7 @@ import kademlia.serializer.JsonSerializer;
  * @todo If we're trying to send a message to this node, just cancel the sending process and handle the message right here
  * @todo Keep this node in it's own routing table - it helps for ContentRefresh operation - easy to check whether this node is one of the k-nodes for a content
  * @todo Move DHT.getContentStorageFolderName to the Configuration class
+ * @todo Implement Kademlia.ping() operation.
  *
  */
 public class Kademlia
@@ -152,7 +154,7 @@ public class Kademlia
          * @section Read the DHT
          */
         din = new DataInputStream(new FileInputStream(getStateStorageFolderName(ownerId) + File.separator + "dht.kns"));
-        DHT idht = new JsonSerializer<DHT>().read(din);
+        DHT idht = new JsonDHTSerializer().read(din);
         System.out.println("Finished reading data.");
         return new Kademlia(ownerId, inode, ikad.getPort(), idht);
     }
@@ -319,7 +321,7 @@ public class Kademlia
          * @section Save the DHT
          */
         dout = new DataOutputStream(new FileOutputStream(getStateStorageFolderName(this.ownerId) + File.separator + "dht.kns"));
-        new JsonSerializer<DHT>().write(this.dht, dout);
+        new JsonDHTSerializer().write(this.dht, dout);
 
         System.out.println("FInished saving state");
 
@@ -381,6 +383,11 @@ public class Kademlia
         sb.append(this.localNode.getRoutingTable());
         sb.append("\n");
 
+        sb.append("\n");
+        sb.append("DHT: ");
+        sb.append(this.dht);
+        sb.append("\n");
+
         sb.append("\n\n\n");
 
         return sb.toString();

src/kademlia/dht/DHT.java

@@ -23,15 +23,27 @@ import kademlia.serializer.JsonSerializer;
 public class DHT
 {
 
-    private final StorageEntryManager entriesManager;
+    private transient StorageEntryManager entriesManager;
     private transient final JsonSerializer<KadContent> contentSerializer;
 
     
     {
-        entriesManager = new StorageEntryManager();
         contentSerializer = new JsonSerializer<>();
     }
 
+    public DHT()
+    {
+        this.initialize();
+    }
+
+    /**
+     * Initialize this DHT to it's default state
+     */
+    public final void initialize()
+    {
+        entriesManager = new StorageEntryManager();
+    }
+
     /**
      * Handle storing content locally
      *
@@ -178,4 +190,24 @@ public class DHT
     {
         return entriesManager.getAllEntries();
     }
+
+    /**
+     * Used to add a list of storage entries for existing content to the DHT.
+     * Mainly used when retrieving StorageEntries from a saved state file.
+     *
+     * @param ientries The entries to add
+     */
+    public void putStorageEntries(List<StorageEntry> ientries)
+    {
+        for (StorageEntry e : ientries)
+        {
+            this.entriesManager.put(e);
+        }
+    }
+
+    @Override
+    public String toString()
+    {
+        return this.entriesManager.toString();
+    }
 }

src/kademlia/dht/StorageEntry.java

@@ -70,12 +70,7 @@ public class StorageEntry
         }
 
         /* Check that key matches */
-        if ((params.getKey() != null) && (!params.getKey().equals(this.key)))
-        {
-            return false;
-        }
-
-        return true;
+        return ((params.getKey() != null) && (!params.getKey().equals(this.key)));
     }
 
     @Override
@@ -98,4 +93,23 @@ public class StorageEntry
         hash = 23 * hash + Objects.hashCode(this.type);
         return hash;
     }
+
+    @Override
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder("[StorageEntry: ");
+
+        sb.append("{Key: ");
+        sb.append(this.key);
+        sb.append("} ");
+        sb.append("{Owner: ");
+        sb.append(this.ownerId);
+        sb.append("} ");
+        sb.append("{Type: ");
+        sb.append(this.type);
+        sb.append("} ");
+        sb.append("]");
+        
+        return sb.toString();
+    }
 }

src/kademlia/dht/StorageEntryManager.java

@@ -16,7 +16,7 @@ import kademlia.node.NodeId;
  * @author Joshua Kissoon
  * @since 20140226
  */
-public class StorageEntryManager
+class StorageEntryManager
 {
 
     private final Map<NodeId, List<StorageEntry>> entries;
@@ -34,6 +34,16 @@ public class StorageEntryManager
     public void put(KadContent content)
     {
         StorageEntry entry = new StorageEntry(content);
+        this.put(entry);
+    }
+
+    /**
+     * Add a new entry to our storage
+     *
+     * @param entry The StorageEntry to store
+     */
+    public void put(StorageEntry entry)
+    {
         if (!this.entries.containsKey(entry.getKey()))
         {
             this.entries.put(entry.getKey(), new ArrayList<StorageEntry>());
@@ -116,4 +126,26 @@ public class StorageEntryManager
 
         return entriesRet;
     }
+
+    @Override
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder("Stored Content: \n");
+        for (List<StorageEntry> es : this.entries.values())
+        {
+            if (entries.size() < 1)
+            {
+                continue;
+            }
+
+            for (StorageEntry e : es)
+            {
+                sb.append(e);
+                sb.append("\n");
+            }
+        }
+
+        sb.append("\n");
+        return sb.toString();
+    }
 }

src/kademlia/routing/RoutingTable.java

@@ -30,12 +30,24 @@ public class RoutingTable
         this.localNode = localNode;
 
         /* Initialize all of the buckets to a specific depth */
-        this.initializeBuckets();
+        this.initialize();
 
         /* @todo Insert the local node */
         //this.insert(localNode);
     }
 
+    /**
+     * Initialize the RoutingTable to it's default state
+     */
+    public final void initialize()
+    {
+        this.buckets = new KadBucket[NodeId.ID_LENGTH];
+        for (int i = 0; i < NodeId.ID_LENGTH; i++)
+        {
+            buckets[i] = new KadBucket(i);
+        }
+    }
+
     /**
      * Adds a new node to the routing table
      *
@@ -180,18 +192,6 @@ public class RoutingTable
         this.buckets = buckets;
     }
 
-    /**
-     * Initialize the kadBuckets to be empty
-     */
-    public final void initializeBuckets()
-    {
-        this.buckets = new KadBucket[NodeId.ID_LENGTH];
-        for (int i = 0; i < NodeId.ID_LENGTH; i++)
-        {
-            buckets[i] = new KadBucket(i);
-        }
-    }
-
     @Override
     public final String toString()
     {

src/kademlia/serializer/JsonDHTSerializer.java

@@ -0,0 +1,94 @@
+package kademlia.serializer;
+
+import com.google.gson.Gson;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.lang.reflect.Type;
+import java.util.List;
+import kademlia.dht.DHT;
+import kademlia.dht.StorageEntry;
+
+/**
+ * A KadSerializer that serializes DHT to JSON format
+ * The generic serializer is not working for DHT
+ *
+ * Why a DHT specific serializer?
+ * The DHT structure:
+ * - DHT
+ * -- StorageEntriesManager
+ * --- Map<NodeId, List<StorageEntry>>
+ * ---- NodeId:KeyBytes
+ * ---- List<StorageEntry>
+ * ----- StorageEntry: Key, OwnerId, Type, Hash
+ *
+ * The above structure seems to be causing some problem for Gson, especially at the Map part.
+ *
+ * Solution
+ * - Make the StorageEntriesManager transient
+ * - Simply store all StorageEntry in the serialized object
+ * - When reloading, re-add all StorageEntry to the DHT
+ *
+ * @author Joshua Kissoon
+ *
+ * @since 20140310
+ */
+public class JsonDHTSerializer implements KadSerializer<DHT>
+{
+
+    private final Gson gson;
+    private final Type storageEntriesCollectionType;
+
+    
+    {
+        gson = new Gson();
+
+        storageEntriesCollectionType = new TypeToken<List<StorageEntry>>()
+        {
+        }.getType();
+    }
+
+    @Override
+    public void write(DHT data, DataOutputStream out) throws IOException
+    {
+        try (JsonWriter writer = new JsonWriter(new OutputStreamWriter(out)))
+        {
+            writer.beginArray();
+
+            /* Write the basic DHT */
+            gson.toJson(data, DHT.class, writer);
+
+            /* Now Store the Entries  */
+            gson.toJson(data.getStorageEntries(), this.storageEntriesCollectionType, writer);
+
+            writer.endArray();
+        }
+
+    }
+
+    @Override
+    public DHT read(DataInputStream in) throws IOException, ClassNotFoundException
+    {
+        try (DataInputStream din = new DataInputStream(in);
+                JsonReader reader = new JsonReader(new InputStreamReader(in)))
+        {
+            reader.beginArray();
+
+            /* Read the basic DHT */
+            DHT dht = gson.fromJson(reader, DHT.class);
+            dht.initialize();
+
+            /* Now get the entries and add them back to the DHT */
+            List<StorageEntry> entries = gson.fromJson(reader, this.storageEntriesCollectionType);
+            dht.putStorageEntries(entries);
+
+            reader.endArray();
+            return dht;
+        }
+    }
+}

src/kademlia/serializer/JsonRoutingTableSerializer.java

@@ -36,7 +36,7 @@ import kademlia.node.Node;
  *
  * @author Joshua Kissoon
  *
- * @since 20140225
+ * @since 20140310
  */
 public class JsonRoutingTableSerializer implements KadSerializer<RoutingTable>
 {
@@ -85,7 +85,7 @@ public class JsonRoutingTableSerializer implements KadSerializer<RoutingTable>
             {
             }.getType();
             List<Node> nodes = gson.fromJson(reader, collectionType);
-            tbl.initializeBuckets();
+            tbl.initialize();
 
             for (Node n : nodes)
             {

src/kademlia/tests/DHTContentImpl.java

@@ -73,6 +73,6 @@ public class DHTContentImpl implements KadContent
 
     public String toString()
     {
-        return "DHTContentImpl[data=" + this.data + "]";
+        return "DHTContentImpl[{data=" + this.data + "{ {key:"+this.key + "}]";
     }
 }

src/kademlia/tests/SaveStateTest.java

@@ -12,21 +12,28 @@ import kademlia.node.NodeId;
 public class SaveStateTest
 {
 
-    public static void main(String[] args)
+    public SaveStateTest()
     {
         try
         {
             /* Setting up 2 Kad networks */
-            Kademlia kad1 = new Kademlia("JoshuaK", new NodeId("ASF45678947584567467"), 7574);
-            Kademlia kad2 = new Kademlia("Crystal", new NodeId("ASERTKJDHGVHERJHGFLK"), 7572);
+            Kademlia kad1 = new Kademlia("JoshuaK", new NodeId("ASF45678947584567467"), 7529);
+            Kademlia kad2 = new Kademlia("Crystal", new NodeId("ASERTKJDHGVHERJHGFLK"), 7532);
 
             /* Connecting 2 to 1 */
             System.out.println("Connecting Kad 1 and Kad 2");
             kad1.connect(kad2.getNode());
-                        
+
+            synchronized (this)
+            {
+                DHTContentImpl c = new DHTContentImpl(kad2.getOwnerId(), "Some Data");
+                System.out.println(c);
+                kad2.put(c);
+            }
+
             System.out.println(kad1);
             System.out.println(kad2);
-            
+
             /* Shutting down kad1 and restarting it */
             System.out.println("\n\n\nShutting down Kad instance");
             kad1.shutdown();
@@ -40,4 +47,9 @@ public class SaveStateTest
             e.printStackTrace();;
         }
     }
+
+    public static void main(String[] args)
+    {
+        new SaveStateTest();
+    }
 }