org.jgroups.blocks

Class ReplicatedTree

public class ReplicatedTree extends Object implements 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
static class	ReplicatedTree.Node
interface	ReplicatedTree.ReplicatedTreeListener

Field Summary
protected Log	log
static String	SEPARATOR

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

Method Summary
void	addReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)
void	block() Block sending and receiving of messages until viewAccepted() is called
boolean	exists(String fqn) Checks whether a given node exists in the tree
void	fetchState(long timeout) Fetch the group state from the current coordinator.
Object	get(String fqn, 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
Set	getChildrenNames(String fqn) Returns all children of a given node
int	getGroupMembersNumber() Returns the number of current members joined to the group
String	getGroupName() Returns the name of the group that the DistributedTree is connected to
Set	getKeys(String fqn) Gets the keys of the `data` map.
Address	getLocalAddress()
Vector	getMembers()
byte[]	getState() Return a copy of the current cache (tree)
static void	main(String[] args)
String	print(String fqn) Prints a representation of the node defined by `fqn`.
void	put(String fqn, HashMap data) Adds a new node to the tree and sets its data.
void	put(String fqn, String key, Object value) Adds a key and value to a given node.
void	receive(Message msg) Callback.
void	remove(String fqn) Removes the node from the tree.
void	remove(String fqn, 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
String	toString()
void	viewAccepted(View new_view)
void	_put(String fqn, HashMap data)
void	_put(String fqn, String key, Object value)
void	_remove(String fqn)
void	_remove(String fqn, String key)
void	_removeData(String fqn)

Field Detail

Constructor Detail

ReplicatedTree

public ReplicatedTree(String groupname, String props, long state_fetch_timeout)

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

ReplicatedTree

public ReplicatedTree(String groupname, String props, long state_fetch_timeout, boolean jmx)

ReplicatedTree

public ReplicatedTree(JChannel channel)

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

Method Detail

addReplicatedTreeListener

public void addReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)

block

public void block()

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

exists

public boolean exists(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

fetchState

public void fetchState(long timeout)

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

get

public Object get(String fqn, 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.

getChannel

public Channel getChannel()

Returns the Channel the DistributedTree is connected to

Returns: Channel

getChildrenNames

public Set getChildrenNames(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)

getGroupMembersNumber

public int getGroupMembersNumber()

Returns the number of current members joined to the group

Returns: int

getGroupName

public String getGroupName()

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

Returns: String

getKeys

public Set getKeys(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)

getState

public byte[] getState()

Return a copy of the current cache (tree)

print

public String print(String fqn)

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

put

public void put(String fqn, 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(String fqn, String key, 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

receive

public void receive(Message msg)

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

remove

public void remove(String fqn)

Removes the node from the tree.

Parameters: fqn The fully qualified name of the node.

remove

public void remove(String fqn, String key)

Removes key from the node's hashmap

Parameters: fqn The fullly qualified name of the node key The key to be removed