NodeId.getFirstSetBitIndex was actually returning a distance value, but without a comparison, was confusing things.

Created a distance function to replace that.

Still working on Refresh Operations
This commit is contained in:
Joshua Kissoon 2014-03-06 12:49:15 +05:30
parent 825c2ca13f
commit f91dea9e5f
4 changed files with 56 additions and 53 deletions

View File

@ -1,8 +1,6 @@
package kademlia.node; package kademlia.node;
import java.io.DataInput;
import java.io.DataInputStream; import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream; import java.io.DataOutputStream;
import java.io.IOException; import java.io.IOException;
import java.net.InetAddress; import java.net.InetAddress;
@ -180,13 +178,13 @@ public class Node implements Streamable
//System.out.println("\n **************** Compare Starting **************** "); //System.out.println("\n **************** Compare Starting **************** ");
//System.out.println("Comparing to: " + this.nodeId); //System.out.println("Comparing to: " + this.nodeId);
int index1 = nodeId.xor(n1.getNodeId()).getFirstSetBitIndex(); int distance1 = nodeId.getDistance(n1.getNodeId());
//System.out.println("Node " + n1.getNodeId() + " distance: " + index1); //System.out.println("Node " + n1.getNodeId() + " distance: " + index1);
int index2 = nodeId.xor(n2.getNodeId()).getFirstSetBitIndex(); int distance2 = nodeId.getDistance(n2.getNodeId());
//System.out.println("Node " + n2.getNodeId() + " distance: " + index2); //System.out.println("Node " + n2.getNodeId() + " distance: " + index2);
int retval; int retval;
if (index1 < index2) if (distance1 < distance2)
{ {
/* If the first node is closer to the given node, return 1 */ /* If the first node is closer to the given node, return 1 */
retval = 1; retval = 1;

View File

@ -83,7 +83,6 @@ public class NodeId implements Streamable
@Override @Override
public boolean equals(Object o) public boolean equals(Object o)
{ {
if (o instanceof NodeId) if (o instanceof NodeId)
{ {
NodeId nid = (NodeId) o; NodeId nid = (NodeId) o;
@ -100,28 +99,6 @@ public class NodeId implements Streamable
return hash; return hash;
} }
/**
* Checks if a given NodeId is less than this NodeId
*
* @param nid The NodeId to compare to this NodeId
*
* @return boolean Whether the given NodeId is less than this NodeId
*/
public boolean lessThan(NodeId nid)
{
byte[] nidBytes = nid.getBytes();
for (int i = 0; i < ID_LENGTH; i++)
{
if (this.keyBytes[i] != nidBytes[i])
{
return this.keyBytes[i] < nidBytes[i];
}
}
/* We got here means they're equal */
return false;
}
/** /**
* Checks the distance between this and another NodeId * Checks the distance between this and another NodeId
* *
@ -147,9 +124,22 @@ public class NodeId implements Streamable
} }
/** /**
* Checks the number of leading 0's in this NodeId * Generates a NodeId that is some distance away from this NodeId
* *
* @return int The number of leading 0's * @param distance
*
* @return NodeId The newly generated NodeId
*/
public NodeId generateNodeIdByDistance(int distance)
{
byte[] result = new byte[ID_LENGTH / 8];
int emptyBytes = distance / 8;
}
/**
* Counts the number of leading 0's in this NodeId
*
* @return Integer The number of leading 0's
*/ */
public int getFirstSetBitIndex() public int getFirstSetBitIndex()
{ {
@ -185,7 +175,24 @@ public class NodeId implements Streamable
break; break;
} }
} }
return ID_LENGTH - prefixLength; return prefixLength;
}
/**
* Gets the distance from this NodeId to another NodeId
*
* @param to
*
* @return Integer The distance
*/
public int getDistance(NodeId to)
{
/**
* Compute the xor of this and to
* Get the index i of the first set bit of the xor returned NodeId
* The distance between them is ID_LENGTH - i
*/
return ID_LENGTH - this.xor(to).getFirstSetBitIndex();
} }
@Override @Override

View File

@ -36,7 +36,7 @@ public class BucketRefreshOperation implements Operation
/* Test whether each nodeId in this list is a different distance from our current NID */ /* Test whether each nodeId in this list is a different distance from our current NID */
for (NodeId nid : refreshIds) for (NodeId nid : refreshIds)
{ {
System.out.println(nid.xor(localNode.getNodeId()).getFirstSetBitIndex()); System.out.println(localNode.getNodeId().getDistance(nid));
} }
/* @todo Do a Node Lookup operation to refresh K-Buckets */ /* @todo Do a Node Lookup operation to refresh K-Buckets */

View File

@ -40,10 +40,8 @@ public class RoutingTable
*/ */
public void insert(Node n) public void insert(Node n)
{ {
/* Find the first set bit: how far this node is away from the contact node */ /* bucketId is the distance between these nodes */
NodeId id = this.localNode.getNodeId().xor(n.getNodeId()); int bucketId = this.localNode.getNodeId().getDistance(n.getNodeId()) - 1;
//System.out.println(" First Bit Set: " + id.getFirstSetBitIndex());
int bucketId = id.getFirstSetBitIndex();
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);
@ -59,7 +57,7 @@ public class RoutingTable
public void remove(Node n) public void remove(Node n)
{ {
/* Find the first set bit: how far this node is away from the contact node */ /* Find the first set bit: how far this node is away from the contact node */
int bucketId = this.localNode.getNodeId().xor(n.getNodeId()).getFirstSetBitIndex(); int bucketId = this.localNode.getNodeId().getDistance(n.getNodeId());
/* If the bucket has the contact, remove it */ /* If the bucket has the contact, remove it */
if (this.buckets[bucketId].containNode(n)) if (this.buckets[bucketId].containNode(n))
@ -80,11 +78,11 @@ public class RoutingTable
{ {
List<Node> closest = new ArrayList<>(num); List<Node> closest = new ArrayList<>(num);
/* Get the bucket number to search for closest from */ /* Get the bucket index to search for closest from */
int bucketNumber = this.localNode.getNodeId().xor(target).getFirstSetBitIndex() - 1; int bucketIndex = this.localNode.getNodeId().getDistance(target) - 1;
/* Add the contacts from this bucket to the return contacts */ /* Add the contacts from this bucket to the return contacts */
for (Node c : this.buckets[bucketNumber].getNodes()) for (Node c : this.buckets[bucketIndex].getNodes())
{ {
if (closest.size() < num) if (closest.size() < num)
{ {
@ -102,12 +100,12 @@ public class RoutingTable
} }
/* If we still need more nodes, we add from buckets on either side of the closest bucket */ /* If we still need more nodes, we add from buckets on either side of the closest bucket */
for (int i = 1; ((bucketNumber - i) >= 0 || (bucketNumber + i) < NodeId.ID_LENGTH); i++) for (int i = 1; ((bucketIndex - i) >= 0 || (bucketIndex + i) < NodeId.ID_LENGTH); i++)
{ {
/* Check the bucket on the left side */ /* Check the bucket on the left side */
if (bucketNumber - i > 0) if (bucketIndex - i > 0)
{ {
for (Node c : this.buckets[bucketNumber - i].getNodes()) for (Node c : this.buckets[bucketIndex - i].getNodes())
{ {
if (closest.size() < num) if (closest.size() < num)
{ {
@ -121,9 +119,9 @@ public class RoutingTable
} }
/* Check the bucket on the right side */ /* Check the bucket on the right side */
if (bucketNumber + i < NodeId.ID_LENGTH) if (bucketIndex + i < NodeId.ID_LENGTH)
{ {
for (Node c : this.buckets[bucketNumber + i].getNodes()) for (Node c : this.buckets[bucketIndex + i].getNodes())
{ {
if (closest.size() < num) if (closest.size() < num)
{ {
@ -179,28 +177,28 @@ public class RoutingTable
{ {
/* Construct a NodeId that is i bits away from the current node Id */ /* Construct a NodeId that is i bits away from the current node Id */
System.out.println("\nGenerating a new NodeId "); System.out.println("\nGenerating a new NodeId ");
BitSet temp = new BitSet(NodeId.ID_LENGTH); BitSet bits = new BitSet(160);
/* Fill the first i parts with 1 */ /* Fill the first i parts with 1 */
for (int j = 0; j < i; j++) for (int j = 0; j < i + 10; j++)
{ {
System.out.println("Got here 1 - j: " + j); bits.set(j);
temp.set(j); System.out.println("Got here 1 - j: " + j + "; bits: " + bits);
} }
/* Fill the last parts with 0 */ /* Fill the last parts with 0 */
for (int j = i; j < NodeId.ID_LENGTH; j++) for (int j = i; j < NodeId.ID_LENGTH; j++)
{ {
System.out.println("Got here 2 - j: " + j); bits.clear(j);
temp.set(j, false); System.out.println("Got here 2 - j: " + j + "; bits: " + bits);
} }
/** /**
* LocalNode NodeId xor the Bits we generated will give a new NodeId * 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 * i distance away from our LocalNode NodeId, we add this to our refreshList
*/ */
System.out.println("Bits: " + temp); System.out.println("Bits: " + bits.toByteArray());
NodeId nid = this.localNode.getNodeId().xor(new NodeId(temp.toByteArray())); NodeId nid = this.localNode.getNodeId().xor(new NodeId(bits.toByteArray()));
System.out.println("NodeId: " + nid); System.out.println("NodeId: " + nid);
refreshList.add(nid); refreshList.add(nid);
} }