rice.pastry
Class NodeHandle

java.lang.Object
  java.util.Observable
      rice.p2p.commonapi.NodeHandle
          rice.pastry.NodeHandle

All Implemented Interfaces:

java.io.Serializable, MessageReceiver

Direct Known Subclasses:

DirectNodeHandle, DistNodeHandle, LeafSetTest.TestNodeHandle

public abstract class NodeHandle

extends NodeHandle

implements MessageReceiver

Interface for handles to remote nodes.

Version:

$Id: NodeHandle.java 3038 2006-02-07 10:01:01Z jeffh $

Author:

Andrew Ladd

See Also:

Serialized Form

Field Summary

static int	LIVENESS_ALIVE
static int	LIVENESS_DEAD
static int	LIVENESS_SUSPECTED
protected PastryNode	localnode
protected Logger	logger

Fields inherited from class rice.p2p.commonapi.NodeHandle

DECLARED_DEAD, DECLARED_LIVE, PROXIMITY_CHANGED

Constructor Summary

NodeHandle()

Method Summary

void	assertLocalNode() May be called from handle etc methods to ensure that local node has been set, either on construction or on deserialization/receivemsg.
void	bootstrap(Message msg) Method which is used by Pastry to start the bootstrapping process on the local node using this handle as the bootstrap handle.
boolean	checkLiveness() Method which FORCES a check of liveness of the remote node.
abstract boolean	equals(java.lang.Object obj) Equality operator for nodehandles.
Id	getId() Returns this node's id.
abstract int	getLiveness() A more detailed version of isAlive().
PastryNode	getLocalNode() Accessor method.
abstract NodeId	getNodeId() Gets the nodeId of this Pastry node.
abstract int	hashCode() Hash codes for nodehandles.
boolean	isAlive() Returns the last known liveness information about the Pastry node associated with this handle.
abstract boolean	ping() Ping the node.
abstract int	proximity() Returns the last known proximity information about the Pastry node associated with this handle.

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface rice.pastry.messaging.MessageReceiver

receiveMessage

Field Detail

LIVENESS_ALIVE

public static final int LIVENESS_ALIVE

See Also:

Constant Field Values

LIVENESS_SUSPECTED

public static final int LIVENESS_SUSPECTED

See Also:

Constant Field Values

LIVENESS_DEAD

public static final int LIVENESS_DEAD

See Also:

Constant Field Values

localnode

protected transient PastryNode localnode

logger

protected transient Logger logger

Constructor Detail

NodeHandle

public NodeHandle()

Method Detail

getNodeId

public abstract NodeId getNodeId()

Gets the nodeId of this Pastry node.

Returns:

the node id.

getId

public Id getId()

Description copied from class: NodeHandle

Returns this node's id.

Specified by:

getId in class NodeHandle

Returns:

The corresponding node's id.

isAlive

public final boolean isAlive()

Returns the last known liveness information about the Pastry node associated with this handle. Invoking this method does not cause network activity.

Specified by:

isAlive in class NodeHandle

Returns:

true if the node is alive, false otherwise.

getLiveness

public abstract int getLiveness()

A more detailed version of isAlive(). This can return 3 states:

Returns:

LIVENESS_ALIVE, LIVENESS_SUSPECTED, LIVENESS_DEAD

checkLiveness

public boolean checkLiveness()

Method which FORCES a check of liveness of the remote node. Note that this method should ONLY be called by internal Pastry maintenance algorithms - this is NOT to be used by applications. Doing so will likely cause a blowup of liveness traffic.

Specified by:

checkLiveness in class NodeHandle

Returns:

true if node is currently alive.

proximity

public abstract int proximity()

Returns the last known proximity information about the Pastry node associated with this handle. Invoking this method does not cause network activity. Smaller values imply greater proximity. The exact nature and interpretation of the proximity metric implementation-specific.

Specified by:

proximity in class NodeHandle

Returns:

the proximity metric value

ping

public abstract boolean ping()

Ping the node. Refreshes the cached liveness status and proximity value of the Pastry node associated with this. Invoking this method causes network activity.

Returns:

true if node is currently alive.

getLocalNode

public final PastryNode getLocalNode()

Accessor method.

assertLocalNode

public void assertLocalNode()

May be called from handle etc methods to ensure that local node has been set, either on construction or on deserialization/receivemsg.

equals

public abstract boolean equals(java.lang.Object obj)

Equality operator for nodehandles.

Overrides:

equals in class java.lang.Object

Parameters:

obj - a nodehandle object

Returns:

true if they are equal, false otherwise.

bootstrap

public void bootstrap(Message msg)

Method which is used by Pastry to start the bootstrapping process on the local node using this handle as the bootstrap handle. Default behavior is simply to call receiveMessage(msg), but transport layer implementations may care to perform other tasks by overriding this method, since the node is not technically part of the ring yet.

Parameters:

msg - the bootstrap message.

hashCode

public abstract int hashCode()

Hash codes for nodehandles.

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code.