Package org.jgroups.blocks

Class DistributedTree

java.lang.Object

org.jgroups.blocks.DistributedTree

All Implemented Interfaces:

MembershipListener, MessageListener

public class DistributedTree
extends java.lang.Object
implements 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, Alfonso Olias-Sanz

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	DistributedTree.DistributedTreeListener
static interface	DistributedTree.ViewListener

Field Summary

Fields

Modifier and Type	Field	Description
protected Channel	channel
protected RpcDispatcher	disp
protected static org.apache.commons.logging.Log	log
protected boolean	rc
protected boolean	send_message	Determines when the updates have to be sent across the network, avoids sending unnecessary messages when there are no member in the group

Constructor Summary

Constructors

Constructor	Description
DistributedTree()
DistributedTree(java.lang.String groupname, java.lang.String channel_properties)
DistributedTree(PullPushAdapter adapter, java.io.Serializable id, long state_timeout)

Method Summary

Modifier and Type	Method	Description
void	_add(java.lang.String fqn)
void	_add(java.lang.String fqn, java.io.Serializable element)
void	_remove(java.lang.String fqn)
void	_reset(java.lang.String fqn, java.io.Serializable element)	similar to set, but does not error if node does not exist, but rather does an add instead
void	_set(java.lang.String fqn, java.io.Serializable element)
void	add(java.lang.String fqn)
void	add(java.lang.String fqn, java.io.Serializable element)
void	add(java.lang.String fqn, java.io.Serializable element, int timeout)
void	addDistributedTreeListener(DistributedTree.DistributedTreeListener listener)
void	addViewListener(DistributedTree.ViewListener listener)
void	block()	Block sending and receiving of messages until ViewAccepted is called
boolean	exists(java.lang.String fqn)
java.io.Serializable	get(java.lang.String fqn)
Channel	getChannel()	Returns the Channel the DistributedTree is connected to
java.util.Vector	getChildrenNames(java.lang.String fqn)	Returns all children of a Node as strings
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.lang.Object	getLocalAddress()
byte[]	getState()	Return a copy of the tree
java.lang.String	print()
void	receive(Message msg)	Called when a message is received.
void	remove(java.lang.String fqn)
void	remove(java.lang.String fqn, int timeout)
void	removeDistributedTreeListener(DistributedTree.DistributedTreeListener listener)
void	removeViewListener(DistributedTree.ViewListener listener)
void	reset(java.lang.String fqn, java.io.Serializable element)	resets an existing node, useful after a merge when you want to tell other members of your state, but do not wish to remove and then add as two separate calls
void	reset(java.lang.String fqn, java.io.Serializable element, int timeout)	resets an existing node, useful after a merge when you want to tell other members of your state, but do not wish to remove and then add as two separate calls
void	set(java.lang.String fqn, java.io.Serializable element)
void	set(java.lang.String fqn, java.io.Serializable element, int timeout)
void	setDeadlockDetection(boolean flag)
void	setState(byte[] data)	Sets the group state; e.g., when joining.
void	start()
void	start(long timeout)
void	stop()
void	suspect(Address suspected_mbr)	Called when a member is suspected
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, toString, wait, wait, wait

Field Detail

channel

protected Channel channel

disp

protected RpcDispatcher disp

rc

protected boolean rc

send_message

protected boolean send_message

Determines when the updates have to be sent across the network, avoids sending unnecessary messages when there are no member in the group

log

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

Constructor Detail

DistributedTree

public DistributedTree()

DistributedTree

public DistributedTree(java.lang.String groupname,
                       java.lang.String channel_properties)

DistributedTree

public DistributedTree(PullPushAdapter adapter,
                       java.io.Serializable id,
                       long state_timeout)
                throws ChannelException

Throws:

ChannelException

Method Detail

getLocalAddress

public java.lang.Object getLocalAddress()

setDeadlockDetection

public void setDeadlockDetection(boolean flag)

start

public void start()
           throws java.lang.Exception

Throws:

java.lang.Exception

start

public void start(long timeout)
           throws java.lang.Exception

Throws:

java.lang.Exception

stop

public void stop()

addDistributedTreeListener

public void addDistributedTreeListener(DistributedTree.DistributedTreeListener listener)

removeDistributedTreeListener

public void removeDistributedTreeListener(DistributedTree.DistributedTreeListener listener)

addViewListener

public void addViewListener(DistributedTree.ViewListener listener)

removeViewListener

public void removeViewListener(DistributedTree.ViewListener listener)

add

public void add(java.lang.String fqn)

add

public void add(java.lang.String fqn,
                java.io.Serializable element)

reset

public void reset(java.lang.String fqn,
                  java.io.Serializable element)

resets an existing node, useful after a merge when you want to tell other members of your state, but do not wish to remove and then add as two separate calls

remove

public void remove(java.lang.String fqn)

add

public void add(java.lang.String fqn,
                java.io.Serializable element,
                int timeout)

reset

public void reset(java.lang.String fqn,
                  java.io.Serializable element,
                  int timeout)

resets an existing node, useful after a merge when you want to tell other members of your state, but do not wish to remove and then add as two separate calls

remove

public void remove(java.lang.String fqn,
                   int timeout)

exists

public boolean exists(java.lang.String fqn)

get

public java.io.Serializable get(java.lang.String fqn)

set

public void set(java.lang.String fqn,
                java.io.Serializable element)

set

public void set(java.lang.String fqn,
                java.io.Serializable element,
                int timeout)

getChildrenNames

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

Returns all children of a Node as strings

print

public java.lang.String print()

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

_add

public void _add(java.lang.String fqn)

_add

public void _add(java.lang.String fqn,
                 java.io.Serializable element)

_remove

public void _remove(java.lang.String fqn)

_set

public void _set(java.lang.String fqn,
                 java.io.Serializable element)

_reset

public void _reset(java.lang.String fqn,
                   java.io.Serializable element)

similar to set, but does not error if node does not exist, but rather does an add instead

receive

public void receive(Message msg)

Description copied from interface: MessageListener

Called when a message is received.

Specified by:

receive in interface MessageListener

getState

public byte[] getState()

Return a copy of the tree

Specified by:

getState in interface MessageListener

Returns:

byte[]

setState

public void setState(byte[] data)

Description copied from interface: MessageListener

Sets the group state; e.g., when joining.

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