rocks.xmpp.core.stream

Class StreamFeaturesManager

java.lang.Object

rocks.xmpp.core.stream.StreamFeaturesManager

public final class StreamFeaturesManager
extends Object

Manages the various features, which are advertised during stream negotiation.

4.3. Stream Negotiation

Because the receiving entity for a stream acts as a gatekeeper to the domains it services, it imposes certain conditions for connecting as a client or as a peer server. At a minimum, the initiating entity needs to authenticate with the receiving entity before it is allowed to send stanzas to the receiving entity (for client-to-server streams this means using SASL as described under Section 6). However, the receiving entity can consider conditions other than authentication to be mandatory-to-negotiate, such as encryption using TLS as described under Section 5. The receiving entity informs the initiating entity about such conditions by communicating "stream features": the set of particular protocol interactions that the initiating entity needs to complete before the receiving entity will accept XML stanzas from the initiating entity, as well as any protocol interactions that are voluntary-to-negotiate but that might improve the handling of an XML stream (e.g., establishment of application-layer compression as described in [XEP-0138]).

Each feature is associated with a feature negotiator, which negotiates the particular feature.

This class manages these negotiators, receives XML elements and delegates them to the responsible feature negotiator for further processing.

It negotiates the stream by sequentially negotiating each stream feature.

Author:

Christian Schudt

Constructor Summary

Constructors

Constructor and Description
StreamFeaturesManager(XmppSession xmppSession) Creates a feature manager.

Method Summary

Modifier and Type	Method and Description
void	addFeatureNegotiator(StreamFeatureNegotiator streamFeatureNegotiator) Adds a new feature negotiator, which is responsible for negotiating an individual feature.
Map<Class<? extends StreamFeature>,StreamFeature>	getFeatures() Gets the available features, which the server has advertised.
void	negotiateNextFeature() Negotiates the next feature.
boolean	processElement(Object element) Tries to process an element, which is a feature or may belong to a feature protocol, e.g. the <proceed/> element from TLS negotiation.
void	processFeatures(StreamFeatures featuresElement) Processes the <stream:features/> element and immediately starts negotiating the first feature.

Methods inherited from class java.lang.Object

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

Constructor Detail

StreamFeaturesManager

public StreamFeaturesManager(XmppSession xmppSession)

Creates a feature manager.

Parameters:

xmppSession - The connection, features will be negotiated for.

Method Detail

getFeatures

public Map<Class<? extends StreamFeature>,StreamFeature> getFeatures()

Gets the available features, which the server has advertised.

Returns:

The features.

addFeatureNegotiator

public void addFeatureNegotiator(StreamFeatureNegotiator streamFeatureNegotiator)

Adds a new feature negotiator, which is responsible for negotiating an individual feature.

Parameters:

streamFeatureNegotiator - The feature negotiator, which is responsible for the feature.

processFeatures

public void processFeatures(StreamFeatures featuresElement)
                     throws Exception

Processes the <stream:features/> element and immediately starts negotiating the first feature.

Parameters:

featuresElement - The <stream:features/> element.

Throws:

Exception - If an exception occurred during feature negotiation.

processElement

public boolean processElement(Object element)
                       throws Exception

Tries to process an element, which is a feature or may belong to a feature protocol, e.g. the <proceed/> element from TLS negotiation.

Parameters:

element - The element.

Returns:

True, if the stream needs restarted, after a feature has been negotiated.

Throws:

Exception - If an exception occurred during feature negotiation.

negotiateNextFeature

public void negotiateNextFeature()
                          throws Exception

Negotiates the next feature. If the feature has been successfully negotiated, the next feature is automatically negotiated.

Throws:

Exception - If an exception occurred during feature negotiation.