org.jgroups.protocols

Class QUEUE

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.QUEUE

public class QUEUE
extends Protocol

Queuing layer. Upon reception of event START_QUEUEING, all events traveling through this layer upwards/downwards (depending on direction of event) will be queued. Upon reception of a STOP_QUEUEING event, all events will be released. Finally, the queueing flag is reset. When queueing, only event STOP_QUEUEING (received up or downwards) will be allowed to release queueing.

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	QUEUE.Observer

Field Summary

Fields inherited from class org.jgroups.stack.Protocol

down_handler, down_prot, down_queue, down_thread, down_thread_prio, log, observer, props, stack, stats, up_handler, up_prot, up_queue, up_thread, up_thread_prio

Constructor Summary

Constructors

Constructor and Description
QUEUE()

Method Summary

Methods

Modifier and Type	Method and Description
void	down(Event evt) An event is to be sent down the stack.
java.util.Vector	getDownVector()
java.lang.String	getName() All protocol names have to be unique !
boolean	getQueueingDown()
boolean	getQueueingUp()
java.util.Vector	getUpVector()
java.util.Vector	providedDownServices() List of events that are provided to layers below (they will be handled when sent down from below).
java.util.Vector	providedUpServices() List of events that are provided to layers above (they will be handled when sent down from above).
void	setObserver(QUEUE.Observer observer) Only 1 observer is allowed.
void	up(Event evt) Queues or passes up events.

Methods inherited from class org.jgroups.stack.Protocol

destroy, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getDownQueue, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, passDown, passUp, printStats, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, resetStats, setDownProtocol, setObserver, setProperties, setPropertiesInternal, setProtocolStack, setUpProtocol, start, startDownHandler, startUpHandler, statsEnabled, stop, stopInternal, upThreadEnabled

Methods inherited from class java.lang.Object

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

Constructor Detail

QUEUE

public QUEUE()

Method Detail

setObserver

public void setObserver(QUEUE.Observer observer)

Only 1 observer is allowed. More than one might slow down the system. Will be called when an event is queued (up or down)

getUpVector

public java.util.Vector getUpVector()

getDownVector

public java.util.Vector getDownVector()

getQueueingUp

public boolean getQueueingUp()

getQueueingDown

public boolean getQueueingDown()

getName

public java.lang.String getName()

All protocol names have to be unique !

Specified by:

getName in class Protocol

providedUpServices

public java.util.Vector providedUpServices()

Description copied from class: Protocol

List of events that are provided to layers above (they will be handled when sent down from above).

Overrides:

providedUpServices in class Protocol

Returns:

Vector (of Integers)

providedDownServices

public java.util.Vector providedDownServices()

Description copied from class: Protocol

List of events that are provided to layers below (they will be handled when sent down from below).

Overrides:

providedDownServices in class Protocol

Returns:

Vector (of Integers)

up

public void up(Event evt)

Queues or passes up events. No queue sync. necessary, as this method is never called concurrently.

Overrides:

up in class Protocol

down

public void down(Event evt)

Description copied from class: Protocol

An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack using passDown(). In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack using passUp().

Overrides:

down in class Protocol