rocks.xmpp.extensions.compress

Class CompressionManager

java.lang.Object

rocks.xmpp.core.session.Manager

rocks.xmpp.core.stream.StreamFeatureNegotiator

rocks.xmpp.extensions.compress.CompressionManager

public final class CompressionManager
extends StreamFeatureNegotiator

Manages stream compression as described in XEP-0138: Stream Compression.

1. Introduction

XMPP Core [1] specifies the use of Transport Layer Security (TLS; see RFC 5246 [2]) for encryption of XML streams, and TLS includes the ability to compress encrypted traffic (see RFC 3749 [3]). However, not all computing platforms are able to implement TLS, and traffic compression may be desirable for communication by applications on such computing platforms. This document defines a mechanism for negotiating the compression of XML streams outside the context of TLS.

If you enable this manager, stream compression will be used, if available. Note that stream compression should not be used, when you use TLS.

Nested Class Summary

Nested classes/interfaces inherited from class rocks.xmpp.core.stream.StreamFeatureNegotiator

StreamFeatureNegotiator.Status

Field Summary

Fields

Modifier and Type	Field and Description
static CompressionMethod	DEFLATE Deprecated. Use CompressionMethod.DEFLATE
static CompressionMethod	GZIP Deprecated. Use CompressionMethod.GZIP
static CompressionMethod	ZLIB Deprecated. Use CompressionMethod.ZLIB

Method Summary

Modifier and Type	Method and Description
boolean	canProcess(Object element) Checks, whether the element can be processed by the feature negotiator.
List<CompressionMethod>	getConfiguredCompressionMethods() Gets the configured compression methods.
CompressionMethod	getNegotiatedCompressionMethod() Gets the negotiated compression method.
boolean	needsRestart() Checks, if the feature needs a stream restart after it has been successfully negotiated.
StreamFeatureNegotiator.Status	processNegotiation(Object element) Processes a feature protocol element or the feature element itself.

Methods inherited from class rocks.xmpp.core.stream.StreamFeatureNegotiator

addFeatureListener, getFeatureClass

Methods inherited from class rocks.xmpp.core.session.Manager

isEnabled, setEnabled

Methods inherited from class java.lang.Object

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

Field Detail

ZLIB

@Deprecated
public static final CompressionMethod ZLIB

Deprecated. Use CompressionMethod.ZLIB

The "zlib" compression method.

GZIP

@Deprecated
public static final CompressionMethod GZIP

Deprecated. Use CompressionMethod.GZIP

The "gzip" compression method.

DEFLATE

@Deprecated
public static final CompressionMethod DEFLATE

Deprecated. Use CompressionMethod.DEFLATE

The "deflate" compression method.

Method Detail

processNegotiation

public final StreamFeatureNegotiator.Status processNegotiation(Object element)
                                                        throws StreamNegotiationException

Description copied from class: StreamFeatureNegotiator

Processes a feature protocol element or the feature element itself.

Specified by:

processNegotiation in class StreamFeatureNegotiator

Parameters:

element - The XML element, which belongs to the feature negotiation, e.g. <challenge/> for SASL negotiation or the feature element itself, e.g. <mechanisms/>.

Returns:

The status of the feature negotiation.

Throws:

StreamNegotiationException - Any exception which might be thrown during a feature negotiation. Note that any exception thrown during the feature negotiation process is thrown by the XmppSession.connect() method and therefore will abort the connection process.

needsRestart

public final boolean needsRestart()

Checks, if the feature needs a stream restart after it has been successfully negotiated. Override this method (returning true), if the feature requires a stream restart after negotiation.

By default this method returns false.

Overrides:

needsRestart in class StreamFeatureNegotiator

Returns:

True, because compression needs a stream restart after feature negotiation.

canProcess

public final boolean canProcess(Object element)

Description copied from class: StreamFeatureNegotiator

Checks, whether the element can be processed by the feature negotiator.

Specified by:

canProcess in class StreamFeatureNegotiator

Parameters:

element - The feature protocol element, e.g. <challenge/>. The element is never the feature element itself, e.g. <mechanisms/>, which is advertised in the <stream:features/> element.

Returns:

True, if the element can be processed by the feature negotiator.

getNegotiatedCompressionMethod

public final CompressionMethod getNegotiatedCompressionMethod()

Gets the negotiated compression method.

Returns:

The negotiated compression method.

getConfiguredCompressionMethods

public final List<CompressionMethod> getConfiguredCompressionMethods()

Gets the configured compression methods.

Returns:

The configured compression method.