org.jgroups.protocols

Class DELAY

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.DELAY

public class DELAY
extends Protocol

Delays incoming/outgoing messages by a random number of milliseconds (range between 0 and n where n is determined by the user) and nanoseconds (constant amount).

Incoming messages can be delayed independently from outgoing messages (or not delayed at all).

This protocol should be inserted directly above the transport protocol (e.g. UDP).

Author:

Bela Ban, Sanne Grinovero, Matej Cimbora

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	constant_delay
protected org.jgroups.protocols.DELAY.DelayedMessageHandler	delayed_message_handler
protected java.util.concurrent.DelayQueue<org.jgroups.protocols.DELAY.DelayedMessage>	delayed_messages
protected int	in_delay
protected int	in_delay_nanos
protected int	out_delay
protected int	out_delay_nanos

Fields inherited from class org.jgroups.stack.Protocol

after_creation_hook, down_prot, ergonomics, id, log, name, stack, stats, up_prot

Constructor Summary

Constructors

Constructor and Description
DELAY()

Method Summary

Modifier and Type	Method and Description
void	destroy() This method is called on a Channel.close().
java.lang.Object	down(Event evt) An event is to be sent down the stack.
int	getInDelay()
int	getInDelayNanos()
int	getOutDelay()
int	getOutDelayNanos()
void	init() Called after instance has been created (null constructor) and before protocol is started.
void	setInDelay(int in_delay)
void	setInDelayNanos(int in_delay_nanos)
void	setOutDelay(int out_delay)
void	setOutDelayNanos(int out_delay_nanos)
java.lang.Object	up(Event evt) An event was received from the layer below.
void	up(MessageBatch batch) Sends up a multiple messages in a MessageBatch.

Methods inherited from class org.jgroups.stack.Protocol

accept, afterCreationHook, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, resetStats, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, start, statsEnabled, stop

Methods inherited from class java.lang.Object

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

Field Detail

in_delay

protected int in_delay

out_delay

protected int out_delay

in_delay_nanos

protected int in_delay_nanos

out_delay_nanos

protected int out_delay_nanos

constant_delay

protected boolean constant_delay

delayed_message_handler

protected org.jgroups.protocols.DELAY.DelayedMessageHandler delayed_message_handler

delayed_messages

protected java.util.concurrent.DelayQueue<org.jgroups.protocols.DELAY.DelayedMessage> delayed_messages

Constructor Detail

DELAY

public DELAY()

Method Detail

getInDelay

public int getInDelay()

setInDelay

public void setInDelay(int in_delay)

getOutDelay

public int getOutDelay()

setOutDelay

public void setOutDelay(int out_delay)

getInDelayNanos

public int getInDelayNanos()

setInDelayNanos

public void setInDelayNanos(int in_delay_nanos)

getOutDelayNanos

public int getOutDelayNanos()

setOutDelayNanos

public void setOutDelayNanos(int out_delay_nanos)

init

public void init()
          throws java.lang.Exception

Description copied from class: Protocol

Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.

Overrides:

init in class Protocol

Throws:

java.lang.Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the channel constructor will throw an exception

destroy

public void destroy()

Description copied from class: Protocol

This method is called on a Channel.close(). Does some cleanup; after the call the VM will terminate

Overrides:

destroy in class Protocol

down

public java.lang.Object 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 down_prot.down(). 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 up_prot.up().

Overrides:

down in class Protocol

up

public java.lang.Object up(Event evt)

Description copied from class: Protocol

An event was received from the layer below. Usually the current layer will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally the event is either a) discarded, or b) an event is sent down the stack using down_prot.down() or c) the event (or another event) is sent up the stack using up_prot.up().

Overrides:

up in class Protocol

up

public void up(MessageBatch batch)

Description copied from class: Protocol

Sends up a multiple messages in a MessageBatch. The sender of the batch is always the same, and so is the destination (null == multicast messages). Messages in a batch can be OOB messages, regular messages, or mixed messages, although the transport itself will create initial MessageBatches that contain only either OOB or regular messages.

The default processing below sends messages up the stack individually, based on a matching criteria (calling Protocol.accept(org.jgroups.Message)), and - if true - calls Protocol.up(org.jgroups.Event) for that message and removes the message. If the batch is not empty, it is passed up, or else it is dropped.

Subclasses should check if there are any messages destined for them (e.g. using MessageBatch.getMatchingMessages(short,boolean)), then possibly remove and process them and finally pass the batch up to the next protocol. Protocols can also modify messages in place, e.g. ENCRYPT could decrypt all encrypted messages in the batch, not remove them, and pass the batch up when done.

Overrides:

up in class Protocol

Parameters:

batch - The message batch