rocks.xmpp.core.stream.client

Class StreamFeaturesManager

java.lang.Object

rocks.xmpp.core.session.Manager

rocks.xmpp.core.stream.client.StreamFeaturesManager

All Implemented Interfaces:

StreamHandler

public final class StreamFeaturesManager
extends Manager
implements StreamHandler

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.

This class is thread-safe.

Method Summary

Modifier and Type	Method and Description
void	addFeatureNegotiator(StreamFeatureNegotiator<? extends StreamFeature> streamFeatureNegotiator) Adds a new feature negotiator, which is responsible for negotiating an individual feature.
java.util.concurrent.Future<java.lang.Void>	awaitNegotiation(java.lang.Class<? extends StreamFeature> streamFeature) Waits until the given feature will be negotiated.
void	cancelNegotiation() Cancels negotiation and releases any locks.
java.util.concurrent.Future<java.lang.Void>	completeNegotiation() Negotiates all pending features, if any, and waits until all features have been negotiated.
java.util.Map<java.lang.Class<? extends StreamFeature>,StreamFeature>	getFeatures() Gets the available features, which the server has advertised.
<T> java.util.List<T>	getFeatures(java.lang.Class<T> clazz)
boolean	handleElement(java.lang.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.
void	removeFeatureNegotiator(StreamFeatureNegotiator<? extends StreamFeature> streamFeatureNegotiator) Removes a feature negotiator.

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

Method Detail

getFeatures

public final java.util.Map<java.lang.Class<? extends StreamFeature>,StreamFeature> getFeatures()

Gets the available features, which the server has advertised.

Returns:

The features.

getFeatures

public final <T> java.util.List<T> getFeatures(java.lang.Class<T> clazz)

addFeatureNegotiator

public final void addFeatureNegotiator(StreamFeatureNegotiator<? extends StreamFeature> 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.

removeFeatureNegotiator

public final void removeFeatureNegotiator(StreamFeatureNegotiator<? extends StreamFeature> streamFeatureNegotiator)

Removes a feature negotiator.

Parameters:

streamFeatureNegotiator - The feature negotiator.

processFeatures

public final void processFeatures(StreamFeatures featuresElement)
                           throws StreamNegotiationException

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

Parameters:

featuresElement - The <stream:features/> element.

Throws:

StreamNegotiationException - If an exception occurred during feature negotiation.

handleElement

public final boolean handleElement(java.lang.Object element)
                            throws StreamNegotiationException

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

Specified by:

handleElement in interface StreamHandler

Parameters:

element - The element.

Returns:

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

Throws:

StreamNegotiationException - If an exception occurred during feature negotiation.

awaitNegotiation

public final java.util.concurrent.Future<java.lang.Void> awaitNegotiation(java.lang.Class<? extends StreamFeature> streamFeature)

Waits until the given feature will be negotiated. If the feature has already been negotiated it immediately returns.

Parameters:

streamFeature - The stream feature class.

Returns:

The future which is complete when the negotiation of the stream feature is completed.

completeNegotiation

public final java.util.concurrent.Future<java.lang.Void> completeNegotiation()
                                                                      throws StreamNegotiationException

Negotiates all pending features, if any, and waits until all features have been negotiated.

Returns:

The future which is complete when all pending features have been negotiated.

Throws:

StreamNegotiationException - If the stream negotiation failed.

cancelNegotiation

public void cancelNegotiation()

Cancels negotiation and releases any locks.