org.jgroups.blocks

Class ReplicatedTree

java.lang.Object

org.jgroups.ReceiverAdapter

org.jgroups.blocks.ReplicatedTree

All Implemented Interfaces:

MembershipListener, MessageListener, Receiver

public class ReplicatedTree
extends ReceiverAdapter

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 and Description
static class	ReplicatedTree.Node
static interface	ReplicatedTree.ReplicatedTreeListener

Field Summary

Fields

Modifier and Type	Field and Description
protected Log	log
static String	SEPARATOR

Constructor Summary

Constructors

Constructor and Description
ReplicatedTree()
ReplicatedTree(JChannel channel) Expects an already connected channel.
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)

Method Summary

Methods

Modifier and Type	Method and Description
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)
void	addReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)
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()
List<Address>	getMembers()
void	getState(OutputStream ostream) Allows an application to write a state through a provided OutputStream.
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	setRemoteCalls(boolean flag)
void	setRootNode(ReplicatedTree.Node n)
void	setState(InputStream istream) Allows an application to read a state through a provided InputStream.
void	start()
void	stop()
String	toString()
void	viewAccepted(View new_view) Called when a change in membership has occurred.

Methods inherited from class org.jgroups.ReceiverAdapter

block, suspect, unblock

Methods inherited from class java.lang.Object

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

Field Detail

SEPARATOR

public static final String SEPARATOR

See Also:

Constant Field Values

log

protected final Log log

Constructor Detail

ReplicatedTree

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

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

Throws:

Exception

ReplicatedTree

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

Throws:

Exception

ReplicatedTree

public ReplicatedTree()

ReplicatedTree

public ReplicatedTree(JChannel channel)
               throws Exception

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

Throws:

Exception

Method Detail

setRemoteCalls

public void setRemoteCalls(boolean flag)

setRootNode

public void setRootNode(ReplicatedTree.Node n)

getLocalAddress

public Address getLocalAddress()

getMembers

public List<Address> getMembers()

fetchState

public void fetchState(long timeout)
                throws Exception

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

Throws:

Exception

addReplicatedTreeListener

public void addReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)

removeReplicatedTreeListener

public void removeReplicatedTreeListener(ReplicatedTree.ReplicatedTreeListener listener)

start

public final void start()
                 throws Exception

Throws:

Exception

stop

public void stop()

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

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

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

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)

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.

print

public String print(String fqn)

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

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)

toString

public String toString()

Overrides:

toString in class Object

getGroupName

public 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(String fqn,
        HashMap data)

_put

public void _put(String fqn,
        String key,
        Object value)

_remove

public void _remove(String fqn)

_remove

public void _remove(String fqn,
           String key)

_removeData

public void _removeData(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

Overrides:

receive in class ReceiverAdapter

getState

public void getState(OutputStream ostream)
              throws Exception

Description copied from class: ReceiverAdapter

Allows an application to write a state through a provided OutputStream. After the state has been written the OutputStream doesn't need to be closed as stream closing is automatically done when a calling thread returns from this callback.

Specified by:

getState in interface MessageListener

Overrides:

getState in class ReceiverAdapter

Parameters:

ostream - the OutputStream

Throws:

Exception - if the streaming fails, any exceptions should be thrown so that the state requester can re-throw them and let the caller know what happened

See Also:

OutputStream.close()

setState

public void setState(InputStream istream)
              throws Exception

Description copied from class: ReceiverAdapter

Allows an application to read a state through a provided InputStream. After the state has been read the InputStream doesn't need to be closed as stream closing is automatically done when a calling thread returns from this callback.

Specified by:

setState in interface MessageListener

Overrides:

setState in class ReceiverAdapter

Parameters:

istream - the InputStream

Throws:

Exception - if the streaming fails, any exceptions should be thrown so that the state requester can catch them and thus know what happened

See Also:

InputStream.close()

viewAccepted

public void viewAccepted(View new_view)

Description copied from class: ReceiverAdapter

Called when a change in membership has occurred. No long running actions, sending of messages or anything that could block 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

Overrides:

viewAccepted in class ReceiverAdapter

main

public static void main(String[] args)