Got system state storage and retrieval of state to work!

src/kademlia/core/Kademlia.java

@@ -9,7 +9,6 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.net.InetAddress;
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Timer;
@@ -26,6 +25,7 @@ import kademlia.operation.Operation;
 import kademlia.operation.KadRefreshOperation;
 import kademlia.operation.StoreOperation;
 import kademlia.routing.RoutingTable;
+import kademlia.serializer.JsonRoutingTableSerializer;
 import kademlia.serializer.JsonSerializer;
 
 /**
@@ -69,6 +69,7 @@ public class Kademlia
      * @param ownerId   The Name of this node used for storage
      * @param localNode The Local Node for this Kad instance
      * @param udpPort   The UDP port to use for routing messages
+     * @param dht       The DHT for this instance
      *
      * @throws IOException If an error occurred while reading id or local map
      *                     from disk <i>or</i> a network error occurred while
@@ -120,24 +121,40 @@ public class Kademlia
      * @return A Kademlia instance loaded from a stored state in a file
      *
      * @throws java.io.FileNotFoundException
+     * @throws java.lang.ClassNotFoundException
      *
      * @todo Boot up this Kademlia instance from a saved file state
      */
-    public static void loadFromFile(String ownerId) throws FileNotFoundException, IOException, ClassNotFoundException
+    public static Kademlia loadFromFile(String ownerId) throws FileNotFoundException, IOException, ClassNotFoundException
     {
-        /* Setup the file in which we store the state */
-        DataInputStream din = new DataInputStream(new FileInputStream(getStateStorageFolderName() + File.separator + ownerId + ".kns"));
+        DataInputStream din;
 
-        /* Read the UDP Port that this app is running on */
-        Integer rPort = new JsonSerializer<Integer>().read(din);
+        /**
+         * @section Read Basic Kad data
+         */
+        din = new DataInputStream(new FileInputStream(getStateStorageFolderName(ownerId) + File.separator + "kad.kns"));
+        Kademlia ikad = new JsonSerializer<Kademlia>().read(din);
 
-        /* Read the node state */
-        // Node rN = new JsonSerializer<Node>().read(din);
+        /**
+         * @section Read the routing table
+         */
+        din = new DataInputStream(new FileInputStream(getStateStorageFolderName(ownerId) + File.separator + "routingtable.kns"));
+        RoutingTable irtbl = new JsonRoutingTableSerializer().read(din);
 
-        /* Read the DHT */
-        DHT rDht = new JsonSerializer<DHT>().read(din);
+        /**
+         * @section Read the node state
+         */
+        din = new DataInputStream(new FileInputStream(getStateStorageFolderName(ownerId) + File.separator + "node.kns"));
+        Node inode = new JsonSerializer<Node>().read(din);
+        inode.setRoutingTable(irtbl);
 
-        //return new Kademlia(ownerId, rN, rPort, rDht);
+        /**
+         * @section Read the DHT
+         */
+        din = new DataInputStream(new FileInputStream(getStateStorageFolderName(ownerId) + File.separator + "dht.kns"));
+        DHT idht = new JsonSerializer<DHT>().read(din);
+        System.out.println("Finished reading data.");
+        return new Kademlia(ownerId, inode, ikad.getPort(), idht);
     }
 
     /**
@@ -242,12 +259,20 @@ public class Kademlia
         return this.ownerId;
     }
 
+    /**
+     * @return Integer The port on which this kad instance is running
+     */
+    public int getPort()
+    {
+        return this.udpPort;
+    }
+
     /**
      * Here we handle properly shutting down the Kademlia instance
      *
      * @throws java.io.FileNotFoundException
      */
-    public void shutdown() throws FileNotFoundException, IOException, ClassNotFoundException
+    public void shutdown() throws FileNotFoundException, IOException
     {
         /* Shut down the server */
         this.server.shutdown();
@@ -257,11 +282,7 @@ public class Kademlia
         {
             /* Save the system state */
             this.saveKadState();
-
         }
-
-
-        /* Now we store the content locally in a file */
     }
 
     /**
@@ -292,7 +313,7 @@ public class Kademlia
          * This will cause a serialization recursion, and in turn a Stack Overflow
          */
         dout = new DataOutputStream(new FileOutputStream(getStateStorageFolderName(this.ownerId) + File.separator + "routingtable.kns"));
-        new JsonSerializer<RoutingTable>().write(this.localNode.getRoutingTable(), dout);
+        new JsonRoutingTableSerializer().write(this.localNode.getRoutingTable(), dout);
 
         /**
          * @section Save the DHT

src/kademlia/node/Node.java

@@ -24,7 +24,7 @@ public class Node implements Streamable
     private InetAddress inetAddress;
     private int port;
 
-    private transient final RoutingTable routingTable;
+    private transient RoutingTable routingTable;
 
     
     {
@@ -119,6 +119,16 @@ public class Node implements Streamable
         return this.routingTable;
     }
 
+    /**
+     * Sets a new routing table to this node, mainly used when we retrieve the node from a saved state
+     *
+     * @param tbl The routing table to use
+     */
+    public void setRoutingTable(RoutingTable tbl)
+    {
+        this.routingTable = tbl;
+    }
+
     @Override
     public boolean equals(Object o)
     {

src/kademlia/node/NodeId.java

@@ -17,7 +17,7 @@ import kademlia.message.Streamable;
 public class NodeId implements Streamable
 {
 
-    public final static int ID_LENGTH = 160;
+    public final transient static int ID_LENGTH = 160;
     private byte[] keyBytes;
 
     /**

src/kademlia/routing/KadBucket.java

@@ -1,8 +1,3 @@
-/**
- * @author Joshua Kissoon
- * @created 20140215
- * @desc A bucket in the Kademlia routing table
- */
 package kademlia.routing;
 
 import java.util.ArrayList;
@@ -12,13 +7,18 @@ import java.util.Map;
 import kademlia.node.Node;
 import kademlia.node.NodeId;
 
+/**
+ * A bucket in the Kademlia routing table
+ *
+ * @author Joshua Kissoon
+ * @created 20140215
+ */
 public class KadBucket implements Bucket
 {
 
     private final int depth;
     private final Map<NodeId, Node> nodes;
     
-    
     {
         nodes = new HashMap<>();
     }

src/kademlia/routing/RoutingTable.java

@@ -1,8 +1,3 @@
-/**
- * @author Joshua Kissoon
- * @created 20140215
- * @desc Implementation of a Kademlia routing table
- */
 package kademlia.routing;
 
 import java.util.ArrayList;
@@ -10,11 +5,20 @@ import java.util.List;
 import kademlia.node.Node;
 import kademlia.node.NodeId;
 
+/**
+ * Implementation of a Kademlia routing table
+ *
+ * @author Joshua Kissoon
+ * @created 20140215
+ *
+ * @todo Make the KadBucket represent the Bucket interface
+ * @todo Change the code to reflect the bucket interface and not the specific KadBucket implementation
+ */
 public class RoutingTable
 {
 
     private final Node localNode;  // The current node
-    private final KadBucket[] buckets;
+    private transient KadBucket[] buckets;
 
     
     {
@@ -26,10 +30,10 @@ public class RoutingTable
         this.localNode = localNode;
 
         /* Initialize all of the buckets to a specific depth */
-        for (int i = 0; i < NodeId.ID_LENGTH; i++)
-        {
-            buckets[i] = new KadBucket(i);
-        }
+        this.initializeBuckets();
+
+        /* @todo Insert the local node */
+        //this.insert(localNode);
     }
 
     /**
@@ -37,10 +41,10 @@ public class RoutingTable
      *
      * @param n The contact to add
      */
-    public void insert(Node n)
+    public final void insert(Node n)
     {
         /* bucketId is the distance between these nodes */
-        int bucketId = this.localNode.getNodeId().getDistance(n.getNodeId()) - 1;
+        int bucketId = this.localNode.getNodeId().getDistance(n.getNodeId());
 
         //System.out.println(this.localNode.getNodeId() + " Adding Node " + n.getNodeId() + " to bucket at depth: " + bucketId);
 
@@ -53,7 +57,7 @@ public class RoutingTable
      *
      * @param n The node to remove
      */
-    public void remove(Node n)
+    public final void remove(Node n)
     {
         /* Find the first set bit: how far this node is away from the contact node */
         int bucketId = this.localNode.getNodeId().getDistance(n.getNodeId());
@@ -73,7 +77,7 @@ public class RoutingTable
      *
      * @return List A List of contacts closest to target
      */
-    public List<Node> findClosest(NodeId target, int num)
+    public final List<Node> findClosest(NodeId target, int num)
     {
         List<Node> closest = new ArrayList<>(num);
 
@@ -146,7 +150,7 @@ public class RoutingTable
     /**
      * @return List A List of all Nodes in this RoutingTable
      */
-    public List getAllNodes()
+    public final List getAllNodes()
     {
         List<Node> nodes = new ArrayList<>();
 
@@ -158,8 +162,38 @@ public class RoutingTable
         return nodes;
     }
 
+    /**
+     * @return Bucket[] The buckets in this Kad Instance
+     */
+    public final KadBucket[] getBuckets()
+    {
+        return this.buckets;
+    }
+
+    /**
+     * Set the KadBuckets of this routing table, mainly used when retrieving saved state
+     *
+     * @param buckets
+     */
+    public final void setBuckets(KadBucket[] buckets)
+    {
+        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 String toString()
+    public final String toString()
     {
         StringBuilder sb = new StringBuilder("\nPrinting Routing Table Started ***************** \n");
         for (KadBucket b : this.buckets)

src/kademlia/serializer/JsonRoutingTableSerializer.java

@@ -0,0 +1,100 @@
+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 kademlia.routing.RoutingTable;
+import java.lang.reflect.Type;
+import java.util.List;
+import kademlia.node.Node;
+
+/**
+ * A KadSerializer that serializes routing tables to JSON format
+ * The generic serializer is not working for routing tables
+ *
+ * Why a RoutingTable specific serializer?
+ * The routing table structure:
+ * - RoutingTable
+ * -- Buckets[]
+ * --- Map<NodeId, Node>
+ * ---- NodeId:KeyBytes
+ * ---- Node: NodeId, InetAddress, Port
+ *
+ * The above structure seems to be causing some problem for Gson,
+ * especially at the Map part.
+ *
+ * Solution
+ * - Make the Buckets[] transient
+ * - Simply store all Nodes in the serialized object
+ * - When reloading, re-add all nodes to the RoutingTable
+ *
+ * @author Joshua Kissoon
+ *
+ * @since 20140225
+ */
+public class JsonRoutingTableSerializer implements KadSerializer<RoutingTable>
+{
+
+    private final Gson gson;
+
+    
+    {
+        gson = new Gson();
+    }
+
+    @Override
+    public void write(RoutingTable data, DataOutputStream out) throws IOException
+    {
+        try (JsonWriter writer = new JsonWriter(new OutputStreamWriter(out)))
+        {
+            writer.beginArray();
+
+            /* Write the basic RoutingTable */
+            gson.toJson(data, RoutingTable.class, writer);
+
+            /* Now Store the Nodes  */
+            Type collectionType = new TypeToken<List<Node>>()
+            {
+            }.getType();
+            gson.toJson(data.getAllNodes(), collectionType, writer);
+
+            writer.endArray();
+        }
+
+    }
+
+    @Override
+    public RoutingTable read(DataInputStream in) throws IOException, ClassNotFoundException
+    {
+        try (DataInputStream din = new DataInputStream(in);
+                JsonReader reader = new JsonReader(new InputStreamReader(in)))
+        {
+            reader.beginArray();
+
+            /* Read the basic RoutingTable */
+            RoutingTable tbl = gson.fromJson(reader, RoutingTable.class);
+
+            /* Now get the nodes and add them back to the RoutingTable */
+            Type collectionType = new TypeToken<List<Node>>()
+            {
+            }.getType();
+            List<Node> nodes = gson.fromJson(reader, collectionType);
+            tbl.initializeBuckets();
+
+            for (Node n : nodes)
+            {
+                tbl.insert(n);
+            }
+
+            reader.endArray();
+            /* Read and return the Content*/
+            return tbl;
+        }
+    }
+}

src/kademlia/serializer/JsonSerializer.java

@@ -58,7 +58,11 @@ public class JsonSerializer<T> implements KadSerializer<T>
             String className = gson.fromJson(reader, String.class);
 
             /* Read and return the Content*/
-            return gson.fromJson(reader, Class.forName(className));
+            T ret = gson.fromJson(reader, Class.forName(className));
+            
+            reader.endArray();
+            
+            return ret;
         }
     }
 }

src/kademlia/tests/SaveStateTest.java

@@ -31,9 +31,9 @@ public class SaveStateTest
             System.out.println("\n\n\nShutting down Kad instance");
             kad1.shutdown();
 
-            //System.out.println("\n\n\nReloading down Kad instance from file");
-            //Kademlia.loadFromFile("JoshuaK");
-            //System.out.println(kad3);
+            System.out.println("\n\n\nReloading down Kad instance from file");
+            Kademlia kad3 = Kademlia.loadFromFile("JoshuaK");
+            System.out.println(kad3);
         }
         catch (Exception e)
         {