Package org.jgroups.blocks

Class ReplicatedTree

java.lang.Object

org.jgroups.blocks.ReplicatedTree

All Implemented Interfaces:

java.lang.Runnable, MembershipListener, MessageListener

public class ReplicatedTree
extends java.lang.Object
implements java.lang.Runnable, MessageListener, MembershipListener

A tree-like structure that is replicated across several members. Updates will be multicast to all group members reliably and in the same order.

Author:

Bela Ban Jan 17 2002, Alfonso Olias-Sanz

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ReplicatedTree.Node
static interface	ReplicatedTree.ReplicatedTreeListener

Field Summary

Fields

Modifier and Type	Field	Description
protected org.apache.commons.logging.Log	log
static java.lang.String	SEPARATOR

Constructor Summary

Constructors

Constructor	Description
ReplicatedTree()
ReplicatedTree(java.lang.String groupname, java.lang.String props, long state_fetch_timeout)	Creates a channel with the given properties.
ReplicatedTree(java.lang.String groupname, java.lang.String props, long state_fetch_timeout, boolean jmx)
ReplicatedTree(JChannel channel)	Expects an already connected channel.

Method Summary

Modifier and Type	Method	Description
void	_put(java.lang.String fqn, java.lang.String key, java.lang.Object value)
void	_put(java.lang.String fqn, java.util.HashMap data)
void	_remove(java.lang.String fqn)
void	_remove(java.lang.String fqn, java.lang.String key)
void	_removeData(java.lang.String fqn)
void	addReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)
void	block()	Block sending and receiving of messages until viewAccepted() is called
boolean	exists(java.lang.String fqn)	Checks whether a given node exists in the tree
void	fetchState(long timeout)	Fetch the group state from the current coordinator.
java.lang.Object	get(java.lang.String fqn, java.lang.String key)	Finds a node given its name and returns the value associated with a given key in its data map.
Channel	getChannel()	Returns the Channel the DistributedTree is connected to
java.util.Set	getChildrenNames(java.lang.String fqn)	Returns all children of a given node
int	getGroupMembersNumber()	Returns the number of current members joined to the group
java.lang.String	getGroupName()	Returns the name of the group that the DistributedTree is connected to
java.util.Set	getKeys(java.lang.String fqn)	Gets the keys of the data map.
Address	getLocalAddress()
java.util.Vector	getMembers()
byte[]	getState()	Return a copy of the current cache (tree)
static void	main(java.lang.String[] args)
java.lang.String	print(java.lang.String fqn)	Prints a representation of the node defined by fqn.
void	put(java.lang.String fqn, java.lang.String key, java.lang.Object value)	Adds a key and value to a given node.
void	put(java.lang.String fqn, java.util.HashMap data)	Adds a new node to the tree and sets its data.
void	receive(Message msg)	Callback.
void	remove(java.lang.String fqn)	Removes the node from the tree.
void	remove(java.lang.String fqn, java.lang.String key)	Removes key from the node's hashmap
void	removeReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)
void	run()	Request handler thread
void	setRemoteCalls(boolean flag)
void	setRootNode(ReplicatedTree.Node n)
void	setState(byte[] new_state)	Set the cache (tree) to this value
void	start()
void	stop()
void	suspect(Address suspected_mbr)	Called when a member is suspected
java.lang.String	toString()
void	viewAccepted(View new_view)	Called when a change in membership has occurred.

Methods inherited from class java.lang.Object

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

Field Detail

SEPARATOR

public static final java.lang.String SEPARATOR

See Also:

Constant Field Values

log

protected final org.apache.commons.logging.Log log

Constructor Detail

ReplicatedTree

public ReplicatedTree(java.lang.String groupname,
                      java.lang.String props,
                      long state_fetch_timeout)
               throws java.lang.Exception

Creates a channel with the given properties. Connects to the channel, then creates a PullPushAdapter and starts it

Throws:

java.lang.Exception

ReplicatedTree

public ReplicatedTree(java.lang.String groupname,
                      java.lang.String props,
                      long state_fetch_timeout,
                      boolean jmx)
               throws java.lang.Exception

Throws:

java.lang.Exception

ReplicatedTree

public ReplicatedTree()

ReplicatedTree

public ReplicatedTree(JChannel channel)
               throws java.lang.Exception

Expects an already connected channel. Creates a PullPushAdapter and starts it

Throws:

java.lang.Exception

Method Detail

setRemoteCalls

public void setRemoteCalls(boolean flag)

setRootNode

public void setRootNode(ReplicatedTree.Node n)

getLocalAddress

public Address getLocalAddress()

getMembers

public java.util.Vector getMembers()

fetchState

public void fetchState(long timeout)
                throws ChannelClosedException,
                       ChannelNotConnectedException

Fetch the group state from the current coordinator. If successful, this will trigger setState().

Throws:

ChannelClosedException

ChannelNotConnectedException

addReplicatedTreeListener

public void addReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)

removeReplicatedTreeListener

public void removeReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)

start

public final void start()
                 throws java.lang.Exception

Throws:

java.lang.Exception

stop

public void stop()

put

public void put(java.lang.String fqn,
                java.util.HashMap data)

Adds a new node to the tree and sets its data. If the node doesn not yet exist, it will be created. Also, parent nodes will be created if not existent. If the node already has data, then the new data will override the old one. If the node already existed, a nodeModified() notification will be generated. Otherwise a nodeCreated() motification will be emitted.

Parameters:

fqn - The fully qualified name of the new node

data - The new data. May be null if no data should be set in the node.

put

public void put(java.lang.String fqn,
                java.lang.String key,
                java.lang.Object value)

Adds a key and value to a given node. If the node doesn't exist, it will be created. If the node already existed, a nodeModified() notification will be generated. Otherwise a nodeCreated() motification will be emitted.

Parameters:

fqn - The fully qualified name of the node

key - The key

value - The value

remove

public void remove(java.lang.String fqn)

Removes the node from the tree.

Parameters:

fqn - The fully qualified name of the node.

remove

public void remove(java.lang.String fqn,
                   java.lang.String key)

Removes key from the node's hashmap

Parameters:

fqn - The fullly qualified name of the node

key - The key to be removed

exists

public boolean exists(java.lang.String fqn)

Checks whether a given node exists in the tree

Parameters:

fqn - The fully qualified name of the node

Returns:

boolean Whether or not the node exists

getKeys

public java.util.Set getKeys(java.lang.String fqn)

Gets the keys of the data map. Returns all keys as Strings. Returns null if node does not exist.

Parameters:

fqn - The fully qualified name of the node

Returns:

Set A set of keys (as Strings)

get

public java.lang.Object get(java.lang.String fqn,
                            java.lang.String key)

Finds a node given its name and returns the value associated with a given key in its data map. Returns null if the node was not found in the tree or the key was not found in the hashmap.

Parameters:

fqn - The fully qualified name of the node.

key - The key.

print

public java.lang.String print(java.lang.String fqn)

Prints a representation of the node defined by fqn. Output includes name, fqn and data.

getChildrenNames

public java.util.Set getChildrenNames(java.lang.String fqn)

Returns all children of a given node

Parameters:

fqn - The fully qualified name of the node

Returns:

Set A list of child names (as Strings)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getGroupName

public java.lang.String getGroupName()

Returns the name of the group that the DistributedTree is connected to

Returns:

String

getChannel

public Channel getChannel()

Returns the Channel the DistributedTree is connected to

Returns:

Channel

getGroupMembersNumber

public int getGroupMembersNumber()

Returns the number of current members joined to the group

Returns:

int

_put

public void _put(java.lang.String fqn,
                 java.util.HashMap data)

_put

public void _put(java.lang.String fqn,
                 java.lang.String key,
                 java.lang.Object value)

_remove

public void _remove(java.lang.String fqn)

_remove

public void _remove(java.lang.String fqn,
                    java.lang.String key)

_removeData

public void _removeData(java.lang.String fqn)

receive

public void receive(Message msg)

Callback. Process the contents of the message; typically an _add() or _set() request

Specified by:

receive in interface MessageListener

getState

public byte[] getState()

Return a copy of the current cache (tree)

Specified by:

getState in interface MessageListener

Returns:

byte[]

setState

public void setState(byte[] new_state)

Set the cache (tree) to this value

Specified by:

setState in interface MessageListener

viewAccepted

public void viewAccepted(View new_view)

Description copied from interface: MembershipListener

Called when a change in membership has occurred. No long running actions or sending of messages should be done in this callback. If some long running action needs to be performed, it should be done in a separate thread.

Note that on reception of the first view (a new member just joined), the channel will not yet be in the connected state. This only happens when Channel.connect(String) returns.

Specified by:

viewAccepted in interface MembershipListener

suspect

public void suspect(Address suspected_mbr)

Called when a member is suspected

Specified by:

suspect in interface MembershipListener

block

public void block()

Block sending and receiving of messages until viewAccepted() is called

Specified by:

block in interface MembershipListener

run

public void run()

Request handler thread

Specified by:

run in interface java.lang.Runnable

main

public static void main(java.lang.String[] args)