Package org.jgroups.protocols

Class COMPRESS

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.COMPRESS

public class COMPRESS
extends Protocol

Compresses the payload of a message. Goal is to reduce the number of messages sent across the wire. Should ideally be layered somewhere above a fragmentation protocol (e.g. FRAG).

Version:

$Id: COMPRESS.java,v 1.19.4.1 2008/11/28 06:08:35 belaban Exp $

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	COMPRESS.CompressHeader

Field Summary

Fields inherited from class org.jgroups.stack.Protocol

down_prot, log, props, stack, stats, up_prot

Constructor Summary

Constructors

Constructor	Description
COMPRESS()

Method Summary

Modifier and Type	Method	Description
void	destroy()	This method is called on a Channel.close().
java.lang.Object	down(Event evt)	We compress the payload if it is larger than min_size.
java.lang.String	getName()
void	init()	Called after instance has been created (null constructor) and before protocol is started.
boolean	setProperties(java.util.Properties props)	Configures the protocol initially.
java.lang.Object	up(Event evt)	If there is no header, we pass the message up.

Methods inherited from class java.lang.Object

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

Methods inherited from class org.jgroups.stack.Protocol

downThreadEnabled, dumpStats, enableStats, getDownProtocol, getProperties, getProtocolStack, getThreadFactory, getTransport, getUpProtocol, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStats, setDownProtocol, setPropertiesInternal, setProtocolStack, setUpProtocol, start, statsEnabled, stop, upThreadEnabled

Constructor Detail

COMPRESS

public COMPRESS()

Method Detail

getName

public java.lang.String getName()

Specified by:

getName in class Protocol

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

setProperties

public boolean setProperties(java.util.Properties props)

Description copied from class: Protocol

Configures the protocol initially. A configuration string consists of name=value items, separated by a ';' (semicolon), e.g.:

 "loopback=false;unicast_inport=4444"
 

Overrides:

setProperties in class Protocol

down

public java.lang.Object down(Event evt)

We compress the payload if it is larger than min_size. In this case we add a header containing the original size before compression. Otherwise we add no header.
Note that we compress either the entire buffer (if offset/length are not used), or a subset (if offset/length are used)

Overrides:

down in class Protocol

Parameters:

evt -

up

public java.lang.Object up(Event evt)

If there is no header, we pass the message up. Otherwise we uncompress the payload to its original size.

Overrides:

up in class Protocol

Parameters:

evt -