Rice Pastry API

rice.pastry.commonapi
Class PastryEndpoint

java.lang.Object
  extended byrice.pastry.client.PastryAppl
      extended byrice.pastry.commonapi.PastryEndpoint
All Implemented Interfaces:
Endpoint, MessageReceiver

public class PastryEndpoint
extends PastryAppl
implements Endpoint

This class serves as gluecode, which allows applications written for the common API to work with pastry.

Version:
$Id: PastryEndpoint.java,v 1.24 2005/08/11 02:53:55 jstewart Exp $
Author:
Alan Mislove, Peter Druschel

Field Summary
protected  Application application
          DESCRIBE THE FIELD
protected  Credentials credentials
          DESCRIBE THE FIELD
protected  java.lang.String instance
          DESCRIBE THE FIELD
 
Fields inherited from class rice.pastry.client.PastryAppl
address, thePastryNode
 
Constructor Summary
PastryEndpoint(PastryNode pn, Application application, int port)
          Constructor.
PastryEndpoint(PastryNode pn, Application application, java.lang.String instance)
          Constructor.
 
Method Summary
 boolean enrouteMessage(Message msg, Id key, NodeId nextHop, SendOptions opt)
          DESCRIBE THE METHOD
 Credentials getCredentials()
          Returns the credentials of this application.
 Environment getEnvironment()
          Gets the Environment attribute of the PastryEndpoint object
 Id getId()
          Returns this node's id, which is its identifier in the namespace.
 java.lang.String getInstance()
          Returns a unique instance name of this endpoint, sort of a mailbox name for this application.
 NodeHandle getLocalNodeHandle()
          Returns a handle to the local node below this endpoint.
 void leafSetChange(NodeHandle nh, boolean wasAdded)
          DESCRIBE THE METHOD
 NodeHandleSet localLookup(Id key, int num, boolean safe)
          This method produces a list of nodes that can be used as next hops on a route towards key, such that the resulting route satisfies the overlay protocol's bounds on the number of hops taken.
 void messageForAppl(Message msg)
          DESCRIBE THE METHOD
 NodeHandleSet neighborSet(int num)
          This method produces an unordered list of nodehandles that are neighbors of the local node in the ID space.
 void process(Executable task, Continuation command)
          Schedules a job for processing on the dedicated processing thread.
 IdRange range(NodeHandle n, int r, Id key)
          This method provides information about ranges of keys for which the node n is currently a r-root.
 IdRange range(NodeHandle n, int r, Id key, boolean cumulative)
          This method provides information about ranges of keys for which the node n is currently a r-root.
 void receiveMessage(Message msg)
          Called by pastry to deliver a message to this client.
 NodeHandleSet replicaSet(Id id, int maxRank)
          This method returns an ordered set of nodehandles on which replicas of the object with key can be stored.
 NodeHandleSet replicaSet(Id id, int maxRank, NodeHandle root, NodeHandleSet set)
          This methods returns an ordered set of nodehandles on which replicas of an object with a given id can be stored.
 void route(Id key, Message msg, NodeHandle hint)
          This operation forwards a message towards the root of key.
 CancellableTask scheduleMessage(Message message, long delay)
          Schedules a message to be delivered to this application after the provided number of milliseconds.
 CancellableTask scheduleMessage(Message message, long delay, long period)
          Schedules a message to be delivered to this application every period number of milliseconds, after delay number of miliseconds have passed.
 
Methods inherited from class rice.pastry.client.PastryAppl
deliverWhenNotReady, destroy, enrouteMessage, getAddress, getLeafSet, getNodeHandle, getNodeId, getRoutingTable, isClosest, notifyReady, registerReceiver, routeMsg, routeMsgDirect, routeSetChange, sendMessage
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

credentials

protected Credentials credentials
DESCRIBE THE FIELD


application

protected Application application
DESCRIBE THE FIELD


instance

protected java.lang.String instance
DESCRIBE THE FIELD

Constructor Detail

PastryEndpoint

public PastryEndpoint(PastryNode pn,
                      Application application,
                      java.lang.String instance)
Constructor.

Parameters:
pn - the pastry node that the application attaches to.
application - DESCRIBE THE PARAMETER
instance - DESCRIBE THE PARAMETER

PastryEndpoint

public PastryEndpoint(PastryNode pn,
                      Application application,
                      int port)
Constructor.

Parameters:
pn - the pastry node that the application attaches to.
application - DESCRIBE THE PARAMETER
port - DESCRIBE THE PARAMETER
Method Detail

getId

public Id getId()
Returns this node's id, which is its identifier in the namespace.

Specified by:
getId in interface Endpoint
Returns:
The local node's id

getLocalNodeHandle

public NodeHandle getLocalNodeHandle()
Returns a handle to the local node below this endpoint.

Specified by:
getLocalNodeHandle in interface Endpoint
Returns:
A NodeHandle referring to the local node.

getCredentials

public Credentials getCredentials()
Returns the credentials of this application.

Specified by:
getCredentials in class PastryAppl
Returns:
the credentials.

getInstance

public java.lang.String getInstance()
Returns a unique instance name of this endpoint, sort of a mailbox name for this application.

Specified by:
getInstance in interface Endpoint
Returns:
The unique instance name of this application

getEnvironment

public Environment getEnvironment()
Gets the Environment attribute of the PastryEndpoint object

Specified by:
getEnvironment in interface Endpoint
Returns:
The Environment value

route

public void route(Id key,
                  Message msg,
                  NodeHandle hint)
This operation forwards a message towards the root of key. The optional hint argument specifies a node that should be used as a first hop in routing the message. A good hint, e.g. one that refers to the key's current root, can result in the message being delivered in one hop; a bad hint adds at most one extra hop to the route. Either K or hint may be NULL, but not both. The operation provides a best-effort service: the message may be lost, duplicated, corrupted, or delayed indefinitely.

Specified by:
route in interface Endpoint
Parameters:
key - the key
msg - the message to deliver.
hint - the hint

scheduleMessage

public CancellableTask scheduleMessage(Message message,
                                       long delay)
Schedules a message to be delivered to this application after the provided number of milliseconds.

Specified by:
scheduleMessage in interface Endpoint
Parameters:
message - The message to be delivered
delay - The number of milliseconds to wait before delivering the message
Returns:
DESCRIBE THE RETURN VALUE

scheduleMessage

public CancellableTask scheduleMessage(Message message,
                                       long delay,
                                       long period)
Schedules a message to be delivered to this application every period number of milliseconds, after delay number of miliseconds have passed.

Specified by:
scheduleMessage in interface Endpoint
Parameters:
message - The message to be delivered
delay - The number of milliseconds to wait before delivering the fist message
period - DESCRIBE THE PARAMETER
Returns:
DESCRIBE THE RETURN VALUE

localLookup

public NodeHandleSet localLookup(Id key,
                                 int num,
                                 boolean safe)
This method produces a list of nodes that can be used as next hops on a route towards key, such that the resulting route satisfies the overlay protocol's bounds on the number of hops taken. If safe is true, the expected fraction of faulty nodes in the list is guaranteed to be no higher than the fraction of faulty nodes in the overlay; if false, the set may be chosen to optimize performance at the expense of a potentially higher fraction of faulty nodes. This option allows applications to implement routing in overlays with byzantine node failures. Implementations that assume fail-stop behavior may ignore the safe argument. The fraction of faulty nodes in the returned list may be higher if the safe parameter is not true because, for instance, malicious nodes have caused the local node to build a routing table that is biased towards malicious nodes~\cite{Castro02osdi}.

Specified by:
localLookup in interface Endpoint
Parameters:
key - the message's key
num - the maximal number of next hops nodes requested
safe -
Returns:
the nodehandle set

neighborSet

public NodeHandleSet neighborSet(int num)
This method produces an unordered list of nodehandles that are neighbors of the local node in the ID space. Up to num node handles are returned.

Specified by:
neighborSet in interface Endpoint
Parameters:
num - the maximal number of nodehandles requested
Returns:
the nodehandle set

replicaSet

public NodeHandleSet replicaSet(Id id,
                                int maxRank)
This method returns an ordered set of nodehandles on which replicas of the object with key can be stored. The call returns nodes with a rank up to and including max_rank. If max_rank exceeds the implementation's maximum replica set size, then its maximum replica set is returned. The returned nodes may be used for replicating data since they are precisely the nodes which become roots for the key when the local node fails.

Specified by:
replicaSet in interface Endpoint
Parameters:
id - DESCRIBE THE PARAMETER
maxRank - DESCRIBE THE PARAMETER
Returns:
the replica set

replicaSet

public NodeHandleSet replicaSet(Id id,
                                int maxRank,
                                NodeHandle root,
                                NodeHandleSet set)
This methods returns an ordered set of nodehandles on which replicas of an object with a given id can be stored. The call returns nodes up to and including a node with maxRank. This call also allows the application to provide a remote "center" node, as well as other nodes in the vicinity.

Specified by:
replicaSet in interface Endpoint
Parameters:
id - The object's id.
maxRank - The number of desired replicas.
set - The set of other nodes around the root handle
root - DESCRIBE THE PARAMETER
Returns:
DESCRIBE THE RETURN VALUE

range

public IdRange range(NodeHandle n,
                     int r,
                     Id key,
                     boolean cumulative)
This method provides information about ranges of keys for which the node n is currently a r-root. The operations returns null if the range could not be determined. It is an error to query the range of a node not present in the neighbor set as returned by the update upcall or the neighborSet call. Some implementations may have multiple, disjoint ranges of keys for which a given node is responsible (Pastry has two). The parameter key allows the caller to specify which range should be returned. If the node referenced by n is the r-root for key, then the resulting range includes key. Otherwise, the result is the nearest range clockwise from key for which n is responsible.

Specified by:
range in interface Endpoint
Parameters:
n - nodeHandle of the node whose range is being queried
r - the rank
key - the key
cumulative - if true, returns ranges for which n is an i-root for 0Returns:
the range of keys, or null if range could not be determined for the given node and rank

range

public IdRange range(NodeHandle n,
                     int r,
                     Id key)
This method provides information about ranges of keys for which the node n is currently a r-root. The operations returns null if the range could not be determined. It is an error to query the range of a node not present in the neighbor set as returned by the update upcall or the neighborSet call. Some implementations may have multiple, disjoint ranges of keys for which a given node is responsible (Pastry has two). The parameter key allows the caller to specify which range should be returned. If the node referenced by n is the r-root for key, then the resulting range includes key. Otherwise, the result is the nearest range clockwise from key for which n is responsible.

Specified by:
range in interface Endpoint
Parameters:
n - nodeHandle of the node whose range is being queried
r - the rank
key - the key
Returns:
the range of keys, or null if range could not be determined for the given node and rank

messageForAppl

public final void messageForAppl(Message msg)
DESCRIBE THE METHOD

Specified by:
messageForAppl in class PastryAppl
Parameters:
msg - DESCRIBE THE PARAMETER

enrouteMessage

public final boolean enrouteMessage(Message msg,
                                    Id key,
                                    NodeId nextHop,
                                    SendOptions opt)
DESCRIBE THE METHOD

Parameters:
msg - DESCRIBE THE PARAMETER
key - DESCRIBE THE PARAMETER
nextHop - DESCRIBE THE PARAMETER
opt - DESCRIBE THE PARAMETER
Returns:
DESCRIBE THE RETURN VALUE

leafSetChange

public void leafSetChange(NodeHandle nh,
                          boolean wasAdded)
DESCRIBE THE METHOD

Overrides:
leafSetChange in class PastryAppl
Parameters:
nh - DESCRIBE THE PARAMETER
wasAdded - DESCRIBE THE PARAMETER

receiveMessage

public void receiveMessage(Message msg)
Called by pastry to deliver a message to this client. Not to be overridden.

Specified by:
receiveMessage in interface MessageReceiver
Overrides:
receiveMessage in class PastryAppl
Parameters:
msg - the message that is arriving.

process

public void process(Executable task,
                    Continuation command)
Schedules a job for processing on the dedicated processing thread. CPU intensive jobs, such as encryption, erasure encoding, or bloom filter creation should never be done in the context of the underlying node's thread, and should only be done via this method.

Specified by:
process in interface Endpoint
Parameters:
task - The task to run on the processing thread
command - The command to return the result to once it's done

Rice Pastry API

Copyright © 2001-2005 - Rice Pastry.


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