rice.p2p.scribe
Class ScribePolicy.DefaultScribePolicy

java.lang.Object
  rice.p2p.scribe.ScribePolicy.DefaultScribePolicy

All Implemented Interfaces:

ScribePolicy

Direct Known Subclasses:

ScribePolicy.LimitedScribePolicy, ScribeRegrTest.TestScribePolicy, SplitStreamScribePolicy

Enclosing interface:

ScribePolicy

public static class ScribePolicy.DefaultScribePolicy
extends java.lang.Object
implements ScribePolicy

The default policy for Scribe, which always allows new children to join and adds children in the order in which they are provided, implicitly providing a depth-first search.

Version:

$Id: ScribePolicy.java 3671 2007-04-10 15:56:31Z jeffh $

Author:

amislove

Nested Class Summary

Nested classes/interfaces inherited from interface rice.p2p.scribe.ScribePolicy

ScribePolicy.DefaultScribePolicy, ScribePolicy.LimitedScribePolicy

Field Summary

protected Environment

environment

Constructor Summary

ScribePolicy.DefaultScribePolicy(Environment env)

Method Summary

java.util.List<Topic>	allowSubscribe(Scribe scribe, NodeHandle source, java.util.List<Topic> topics, ScribeContent content) If you don't override the deprecated allowSubscribe(), This method always return true;
boolean	allowSubscribe(SubscribeMessage message, ScribeClient[] clients, NodeHandle[] children) This method should be deprecated, but is here for reverse compatibility.
void	childAdded(Topic topic, NodeHandle child) Informs this policy that a child was added to a topic - the topic is free to ignore this upcall if it doesn't care.
void	childRemoved(Topic topic, NodeHandle child) Informs this policy that a child was removed from a topic - the topic is free to ignore this upcall if it doesn't care.
void	directAnycast(AnycastMessage message, NodeHandle parent, java.util.Collection<NodeHandle> theChildren) Simply adds the parent and children in order, which implements a depth-first-search.
ScribeContent	divideContent(java.util.List<Topic> theTopics, ScribeContent content) This method is called when the ScribeImpl splits a SubscribeMessage into multiple parts.
void	intermediateNode(ScribeMessage message) This is invoked whenever this message arrives on any overlay node, this gives the ScribeClient's power to tap into some datastructures they might wanna edit
void	recvAnycastFail(Topic topic, NodeHandle failedAtNode, ScribeContent content) This notifies us when we receive a failure for a anycast

Methods inherited from class java.lang.Object

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

Field Detail

environment

protected Environment environment

Constructor Detail

ScribePolicy.DefaultScribePolicy

public ScribePolicy.DefaultScribePolicy(Environment env)

Method Detail

allowSubscribe

public java.util.List<Topic> allowSubscribe(Scribe scribe,
                                            NodeHandle source,
                                            java.util.List<Topic> topics,
                                            ScribeContent content)

If you don't override the deprecated allowSubscribe(), This method always return true;

Specified by:

allowSubscribe in interface ScribePolicy

Parameters:

message - The subscribe message in question

children - The list of children who are currently subscribed

clients - The list of clients are are currently subscribed

Returns:

the topics to accept

allowSubscribe

public boolean allowSubscribe(SubscribeMessage message,
                              ScribeClient[] clients,
                              NodeHandle[] children)

This method should be deprecated, but is here for reverse compatibility. We changed the allowSubscribe() method, but classes that extend DefaultScribePolicy object could make a mistake and not override the new one.

Parameters:

message -

clients -

children -

Returns:

directAnycast

public void directAnycast(AnycastMessage message,
                          NodeHandle parent,
                          java.util.Collection<NodeHandle> theChildren)

Simply adds the parent and children in order, which implements a depth-first-search. randomly picks a child

Specified by:

directAnycast in interface ScribePolicy

Parameters:

message - The anycast message in question

parent - Our current parent for this message's topic

children - Our current children for this message's topic

childAdded

public void childAdded(Topic topic,
                       NodeHandle child)

Informs this policy that a child was added to a topic - the topic is free to ignore this upcall if it doesn't care.

Specified by:

childAdded in interface ScribePolicy

Parameters:

topic - The topic to unsubscribe from

child - The child that was added

childRemoved

public void childRemoved(Topic topic,
                         NodeHandle child)

Informs this policy that a child was removed from a topic - the topic is free to ignore this upcall if it doesn't care.

Specified by:

childRemoved in interface ScribePolicy

Parameters:

topic - The topic to unsubscribe from

child - The child that was removed

intermediateNode

public void intermediateNode(ScribeMessage message)

Description copied from interface: ScribePolicy

This is invoked whenever this message arrives on any overlay node, this gives the ScribeClient's power to tap into some datastructures they might wanna edit

Specified by:

intermediateNode in interface ScribePolicy

recvAnycastFail

public void recvAnycastFail(Topic topic,
                            NodeHandle failedAtNode,
                            ScribeContent content)

Description copied from interface: ScribePolicy

This notifies us when we receive a failure for a anycast

Specified by:

recvAnycastFail in interface ScribePolicy

divideContent

public ScribeContent divideContent(java.util.List<Topic> theTopics,
                                   ScribeContent content)

Description copied from interface: ScribePolicy

This method is called when the ScribeImpl splits a SubscribeMessage into multiple parts. If you modify the content, you must make a copy, as the same content will be passed in for the other divisions of the SubscribeMessage. ScribeContent's are not naturally copyable, so Scribe cannot make a copy apriori.

Specified by:

divideContent in interface ScribePolicy

Parameters:

theTopics - topics going to a particular location

content - the content that may need to be divided

Returns:

the content if not changed, a new ScribeContent if changed