rice.p2p.scribe
Class ScribeImpl

java.lang.Object
  rice.p2p.scribe.ScribeImpl

All Implemented Interfaces:

Destructable, Application, Scribe

public class ScribeImpl

extends java.lang.Object

implements Scribe, Application

Version:

$Id: ScribeImpl.java 2885 2006-01-05 12:20:54Z jeffh $

Author:

Alan Mislove

Nested Class Summary

class

ScribeImpl.TopicManager Class which keeps track of a given topic

Field Summary

protected Endpoint	endpoint this application's endpoint
protected NodeHandle	handle the local node handle
int	MAINTENANCE_INTERVAL The interval with which to perform maintenance
int	MESSAGE_TIMEOUT the timeout for a subscribe message
protected ScribePolicy	policy this scribe's policy
java.util.Hashtable	topics the hashtable of topic -> TopicManager

Constructor Summary

ScribeImpl(Node node, ScribePolicy policy, java.lang.String instance)
Constructor for Scribe

ScribeImpl(Node node, java.lang.String instance)
Constructor for Scribe, using the default policy.

Method Summary

void	addChild(Topic topic, NodeHandle child) Adds a child to the given topic
protected void	addChild(Topic topic, NodeHandle child, int id) Adds a child to the given topic, using the specified sequence number in the ack message sent to the child.
void	anycast(Topic topic, ScribeContent content) Anycasts the given content to a member of the given topic
void	deliver(Id id, Message message) This method is called on the application at the destination node for the given id.
void	destroy()
boolean	forward(RouteMessage message) This method is invoked on applications when the underlying node is about to forward the given message with the provided target to the specified next hop.
NodeHandle[]	getChildren(Topic topic) Returns the list of children for a given topic
ScribeClient[]	getClients(Topic topic) Returns the list of clients for a given topic
Environment	getEnvironment()
Id	getId() Returns the Id of the local node
NodeHandle	getParent(Topic topic) Returns the parent for a given topic
ScribePolicy	getPolicy() Returns the current policy for this scribe object
Topic[]	getTopics(ScribeClient client) Returns the list of topics the given client is subscribed to.
boolean	isRoot(Topic topic) Returns whether or not this Scribe is the root for the given topic
void	publish(Topic topic, ScribeContent content) Publishes the given message to the topic.
void	removeChild(Topic topic, NodeHandle child) Removes a child from the given topic
protected void	removeChild(Topic topic, NodeHandle child, boolean sendDrop) Removes a child from the given topic
void	setPolicy(ScribePolicy policy) Sets the current policy for this scribe object
void	subscribe(Topic topic, ScribeClient client) Subscribes the given client to the provided topic.
void	subscribe(Topic topic, ScribeClient client, ScribeContent content) Subscribes the given client to the provided topic.
void	unsubscribe(Topic topic, ScribeClient client) Unsubscribes the given client from the provided topic.
void	update(NodeHandle handle, boolean joined) This method is invoked to inform the application that the given node has either joined or left the neighbor set of the local node, as the set would be returned by the neighborSet call.

Methods inherited from class java.lang.Object

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

Field Detail

MAINTENANCE_INTERVAL

public final int MAINTENANCE_INTERVAL

The interval with which to perform maintenance

MESSAGE_TIMEOUT

public final int MESSAGE_TIMEOUT

the timeout for a subscribe message

topics

public java.util.Hashtable topics

the hashtable of topic -> TopicManager

policy

protected ScribePolicy policy

this scribe's policy

endpoint

protected Endpoint endpoint

this application's endpoint

handle

protected NodeHandle handle

the local node handle

Constructor Detail

ScribeImpl

public ScribeImpl(Node node,
                  java.lang.String instance)

Constructor for Scribe, using the default policy.

Parameters:

node - The node below this Scribe implementation

instance - The unique instance name of this Scribe

ScribeImpl

public ScribeImpl(Node node,
                  ScribePolicy policy,
                  java.lang.String instance)

Constructor for Scribe

Parameters:

node - The node below this Scribe implementation

policy - The policy for this Scribe

instance - The unique instance name of this Scribe

Method Detail

getEnvironment

public Environment getEnvironment()

Specified by:

getEnvironment in interface Scribe

Returns:

getPolicy

public ScribePolicy getPolicy()

Returns the current policy for this scribe object

Specified by:

getPolicy in interface Scribe

Returns:

The current policy for this scribe

setPolicy

public void setPolicy(ScribePolicy policy)

Sets the current policy for this scribe object

Specified by:

setPolicy in interface Scribe

Parameters:

policy - The current policy for this scribe

getId

public Id getId()

Returns the Id of the local node

Returns:

The Id of the local node

getClients

public ScribeClient[] getClients(Topic topic)

Returns the list of clients for a given topic

Parameters:

topic - The topic to return the clients of

Returns:

The clients of the topic

getChildren

public NodeHandle[] getChildren(Topic topic)

Returns the list of children for a given topic

Specified by:

getChildren in interface Scribe

Parameters:

topic - The topic to return the children of

Returns:

The children of the topic

getParent

public NodeHandle getParent(Topic topic)

Returns the parent for a given topic

Specified by:

getParent in interface Scribe

Parameters:

topic - The topic to return the parent of

Returns:

The parent of the topic

isRoot

public boolean isRoot(Topic topic)

Returns whether or not this Scribe is the root for the given topic

Specified by:

isRoot in interface Scribe

Parameters:

topic - The topic in question

Returns:

Whether or not we are currently the root

subscribe

public void subscribe(Topic topic,
                      ScribeClient client)

Subscribes the given client to the provided topic. Any message published to the topic will be delivered to the Client via the deliver() method.

Specified by:

subscribe in interface Scribe

Parameters:

topic - The topic to subscribe to

client - The client to give messages to

subscribe

public void subscribe(Topic topic,
                      ScribeClient client,
                      ScribeContent content)

Subscribes the given client to the provided topic. Any message published to the topic will be delivered to the Client via the deliver() method.

Specified by:

subscribe in interface Scribe

Parameters:

topic - The topic to subscribe to

client - The client to give messages to

content - The content to include in the subscribe

unsubscribe

public void unsubscribe(Topic topic,
                        ScribeClient client)

Unsubscribes the given client from the provided topic.

Specified by:

unsubscribe in interface Scribe

Parameters:

topic - The topic to unsubscribe from

client - The client to unsubscribe

publish

public void publish(Topic topic,
                    ScribeContent content)

Publishes the given message to the topic.

Specified by:

publish in interface Scribe

Parameters:

topic - The topic to publish to

content - The content to publish

anycast

public void anycast(Topic topic,
                    ScribeContent content)

Anycasts the given content to a member of the given topic

Specified by:

anycast in interface Scribe

Parameters:

topic - The topic to anycast to

content - The content to anycast

addChild

public void addChild(Topic topic,
                     NodeHandle child)

Adds a child to the given topic

Specified by:

addChild in interface Scribe

Parameters:

topic - The topic to add the child to

child - The child to add

addChild

protected void addChild(Topic topic,
                        NodeHandle child,
                        int id)

Adds a child to the given topic, using the specified sequence number in the ack message sent to the child.

Parameters:

topic - The topic

child - THe child to add

id - THe seuqnce number

removeChild

public void removeChild(Topic topic,
                        NodeHandle child)

Removes a child from the given topic

Specified by:

removeChild in interface Scribe

Parameters:

topic - The topic to remove the child from

child - The child to remove

removeChild

protected void removeChild(Topic topic,
                           NodeHandle child,
                           boolean sendDrop)

Removes a child from the given topic

Parameters:

topic - The topic to remove the child from

child - The child to remove

sendDrop - Whether or not to send a drop message to the chil

getTopics

public Topic[] getTopics(ScribeClient client)

Returns the list of topics the given client is subscribed to.

Specified by:

getTopics in interface Scribe

Parameters:

client - The client in question

Returns:

The list of topics

forward

public boolean forward(RouteMessage message)

This method is invoked on applications when the underlying node is about to forward the given message with the provided target to the specified next hop. Applications can change the contents of the message, specify a different nextHop (through re-routing), or completely terminate the message.

Specified by:

forward in interface Application

Parameters:

message - The message being sent, containing an internal message along with a destination key and nodeHandle next hop.

Returns:

Whether or not to forward the message further

deliver

public void deliver(Id id,
                    Message message)

This method is called on the application at the destination node for the given id.

Specified by:

deliver in interface Application

Parameters:

id - The destination id of the message

message - The message being sent

update

public void update(NodeHandle handle,
                   boolean joined)

This method is invoked to inform the application that the given node has either joined or left the neighbor set of the local node, as the set would be returned by the neighborSet call.

Specified by:

update in interface Application

Parameters:

handle - The handle that has joined/left

joined - Whether the node has joined or left

destroy

public void destroy()

Specified by:

destroy in interface Destructable

Specified by:

destroy in interface Scribe