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Finish Bucket Refresh Operation :)

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This commit is contained in:
Joshua Kissoon 2014-03-06 16:24:50 +05:30
parent f91dea9e5f
commit cabb5af742
4 changed files with 62 additions and 79 deletions
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4
src/kademlia/core/KadServer.java
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@ -170,13 +170,13 @@ public class KadServer
Message msg = messageFactory.createMessage(messCode, din);
din.close();
System.out.println(this.localNode.getNodeId() + " Message Received: [Comm: " + comm + "] " + msg);
//System.out.println(this.localNode.getNodeId() + " Message Received: [Comm: " + comm + "] " + msg);
/* Get a receiver for this message */
Receiver receiver;
if (this.receivers.containsKey(comm))
{
System.out.println("Receiver found");
//System.out.println("Receiver found");
/* If there is a reciever in the receivers to handle this */
synchronized (this)
{

34
src/kademlia/node/NodeId.java
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@ -10,6 +10,7 @@ import java.io.DataOutputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Random;
import kademlia.message.Streamable;
@ -126,14 +127,43 @@ public class NodeId implements Streamable
/**
* Generates a NodeId that is some distance away from this NodeId
*
* @param distance
* @param distance in number of bits
*
* @return NodeId The newly generated NodeId
*/
public NodeId generateNodeIdByDistance(int distance)
{
byte[] result = new byte[ID_LENGTH / 8];
int emptyBytes = distance / 8;
/* Since distance = ID_LENGTH - prefixLength, we need to fill that amount with 0's */
int numByteZeroes = (ID_LENGTH - distance) / 8;
int numBitZeroes = 8 - (distance % 8);
/* Filling byte zeroes */
for (int i = 0; i < numByteZeroes; i++)
{
result[i] = 0;
}
/* Filling bit zeroes */
BitSet bits = new BitSet(8);
bits.set(0, 8);
for (int i = 0; i < numBitZeroes; i++)
{
/* Shift 1 zero into the start of the value */
bits.clear(i);
}
bits.flip(0, 8); // Flip the bits since they're in reverse order
result[numByteZeroes] = (byte) bits.toByteArray()[0];
/* Set the remaining bytes to Maximum value */
for (int i = numByteZeroes + 1; i < result.length; i++)
{
result[i] = Byte.MAX_VALUE;
}
return this.xor(new NodeId(result));
}
/**

36
src/kademlia/operation/BucketRefreshOperation.java
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@ -1,7 +1,6 @@
package kademlia.operation;
import java.io.IOException;
import java.util.List;
import kademlia.core.KadServer;
import kademlia.node.Node;
import kademlia.node.NodeId;
@ -25,27 +24,28 @@ public class BucketRefreshOperation implements Operation
this.localNode = localNode;
}
/**
* Each bucket need to be refreshed at every time interval t.
* Find an identifier in each bucket's range, use it to look for nodes closest to this identifier
* allowing the bucket to be refreshed.
*
* Then Do a NodeLookupOperation for each of the generated NodeIds,
* This will find the K-Closest nodes to that ID, and update the necessary K-Bucket
*
* @throws java.io.IOException
*/
@Override
public synchronized void execute() throws IOException
{
System.out.println("Bucket Refresh Operation Started");
/* Get a list of NodeIds for each distance from the LocalNode NodeId */
List<NodeId> refreshIds = this.localNode.getRoutingTable().getRefreshList();
/* Test whether each nodeId in this list is a different distance from our current NID */
for (NodeId nid : refreshIds)
for (int i = 1; i < NodeId.ID_LENGTH; i++)
{
System.out.println(localNode.getNodeId().getDistance(nid));
/* Construct a NodeId that is i bits away from the current node Id */
NodeId current = this.localNode.getNodeId().generateNodeIdByDistance(i);
// System.out.println("Distance: " + localNode.getNodeId().getDistance(current) + " - ID: " + current);
/* Run the Node Lookup Operation */
new NodeLookupOperation(this.server, this.localNode, this.localNode.getNodeId()).execute();
}
/* @todo Do a Node Lookup operation to refresh K-Buckets */
new NodeLookupOperation(this.server, this.localNode, this.localNode.getNodeId()).execute();
/**
* @todo Send data in DHT to closest Nodes if they don't have it
* This is better than asking closest nodes for data,
* since the data may not always come from the closest nodes
*/
}
}

67
src/kademlia/routing/RoutingTable.java
View File

@ -13,15 +13,15 @@ import kademlia.node.NodeId;
public class RoutingTable
{
private final Node localNode; // The current node
private final KadBucket[] buckets;
{
buckets = new KadBucket[NodeId.ID_LENGTH]; // 160 buckets; 1 for each level in the tree
}
public RoutingTable(Node localNode)
{
this.localNode = localNode;
@ -43,7 +43,7 @@ public class RoutingTable
/* bucketId is the distance between these nodes */
int bucketId = this.localNode.getNodeId().getDistance(n.getNodeId()) - 1;
System.out.println(this.localNode.getNodeId() + " Adding Node " + n.getNodeId() + " to bucket at depth: " + bucketId);
//System.out.println(this.localNode.getNodeId() + " Adding Node " + n.getNodeId() + " to bucket at depth: " + bucketId);
/* Put this contact to the bucket that stores contacts prefixLength distance away */
this.buckets[bucketId].insert(n);
@ -93,7 +93,7 @@ public class RoutingTable
break;
}
}
if (closest.size() >= num)
{
return closest;
@ -140,7 +140,7 @@ public class RoutingTable
break;
}
}
return closest;
}
@ -150,62 +150,15 @@ public class RoutingTable
public List getAllNodes()
{
List<Node> nodes = new ArrayList<>();
for (KadBucket b : this.buckets)
{
nodes.addAll(b.getNodes());
}
return nodes;
}
/**
* Each bucket need to be refreshed at every time interval t.
* Here we return an identifier in each bucket's range;
* this identifier will then be used to look for nodes closest to this identifier
* allowing the bucket to be refreshed.
*
* The first bucket containing only the local node is skipped.
*
* @return List A list of NodeIds for each distance (1 - NodeId.ID_LENGTH) from the LocalNode NodeId
*/
public List<NodeId> getRefreshList()
{
List<NodeId> refreshList = new ArrayList<>(NodeId.ID_LENGTH);
for (int i = 1; i < NodeId.ID_LENGTH; i++)
{
/* Construct a NodeId that is i bits away from the current node Id */
System.out.println("\nGenerating a new NodeId ");
BitSet bits = new BitSet(160);
/* Fill the first i parts with 1 */
for (int j = 0; j < i + 10; j++)
{
bits.set(j);
System.out.println("Got here 1 - j: " + j + "; bits: " + bits);
}
/* Fill the last parts with 0 */
for (int j = i; j < NodeId.ID_LENGTH; j++)
{
bits.clear(j);
System.out.println("Got here 2 - j: " + j + "; bits: " + bits);
}
/**
* LocalNode NodeId xor the Bits we generated will give a new NodeId
* i distance away from our LocalNode NodeId, we add this to our refreshList
*/
System.out.println("Bits: " + bits.toByteArray());
NodeId nid = this.localNode.getNodeId().xor(new NodeId(bits.toByteArray()));
System.out.println("NodeId: " + nid);
refreshList.add(nid);
}
return refreshList;
}
@Override
public String toString()
{
@ -225,8 +178,8 @@ public class RoutingTable
}
}
sb.append("\nPrinting Routing Table Ended ******************** ");
return sb.toString();
}
}