Package org.xmpp.component

Class AbstractComponent

  • All Implemented Interfaces:
    Component
    public abstract class AbstractComponent
extends Object
implements Component
    This class provides a default Component implementation. Most of the default functionality can be overridden by overriding specific methods. These XMPP features are implemented in the abstract component:
    • Service Discovery (XEP-0030)
    • XMPP Ping (XEP-0199)
    • Last Activity (XEP-0012)
    • Entity Time(XEP-0202)
    This implementation uses the producer/consumer pattern, in which it takes the role of a consumer of stanzas. Every abstract component has a dedicated thread pool to process stanzas. This pool will use up to the configured maximum amount of threads to process stanzas that are sent to this component. If more stanzas are to be processed simultaneously, they will be placed in a queue (of configurable size) until a thread becomes available again. If the queue is full, the stanza will be dropped and an exception will be logged. If the stanza was an IQ request stanza, an IQ error stanza (internal-server-error/wait) will be returned. By default, instances of this class are guaranteed to return an IQ response on every consumed IQ of the get or set type, as required by the XMPP specification. If the abstract component cannot formulate a valid response and the extending implementation does not provide a response either (by returning null on invocations of handleIQGet(IQ) and handleIQSet(IQ)) an IQ error response is returned. The behavior described above can be disabled by setting a corresponding flag in one of the constructors. If an instance is configured in such a way, null responses provided by the extending implementation are not translated in an IQ error. This allows the extending implementation to respond to IQ requests in an asynchrous manner. It will be up to the extending implementation to ensure that every IQ request is responded to. Note that instances of this class can be used to implement internal (e.g. Openfire plugins) as well as external components.
    Author:
    Guus der Kinderen, guus.der.kinderen@gmail.com

    • Field Detail

      • log

        protected final org.slf4j.Logger log
        The object that's responsible for logging.

      • compMan

        protected ComponentManager compMan
        The component manager to which this Component has been registered.

      • jid

        protected JID jid
        The JID of the component, set after registration with a Component manager.

    • Constructor Detail

      • AbstractComponent

        public AbstractComponent()
        Instantiates a new AbstractComponent with a maximum thread pool size of 17 and a maximum queue size of 1000.

      • AbstractComponent

        public AbstractComponent​(int maxThreadpoolSize,
                         int maxQueueSize,
                         boolean enforceIQResult)
        Instantiates a new AbstractComponent.
        Parameters:
        maxThreadpoolSize - the maximum number of threads that will process work for this component.
        maxQueueSize - capacity of the queue that holds tasks that are to be executed by the thread pool.
        enforceIQResult - if true, the component will make sure that every request that is received is answered, as specified by the XMPP specification.

    • Method Detail

      • dropStanza

        protected boolean dropStanza​(IQ iq)

      • handleIQResult

        protected void handleIQResult​(IQ iq)
        Override this method to handle the IQ stanzas of type result that are received by the component. If you do not override this method, the stanzas are ignored.
        Parameters:
        iq - The IQ stanza of type result that was received by this component.

      • handleIQError

        protected void handleIQError​(IQ iq)
        Override this method to handle the IQ stanzas of type error that are received by the component. If you do not override this method, the stanzas are ignored.
        Parameters:
        iq - The IQ stanza of type error that was received by this component.

      • handleIQGet

        protected IQ handleIQGet​(IQ iq)
                  throws Exception
        Override this method to handle the IQ stanzas of type get that could not be processed by the AbstractComponent implementation.
        Note that, as any IQ stanza of type get must be replied to, returning null from this method equals returning an IQ error stanza of type 'feature-not-implemented' (this behavior can be disabled by setting the enforceIQResult argument in the constructor to false).
        Note that if this method throws an Exception, an IQ stanza of type error, condition 'internal-server-error' will be returned to the sender of the original request.
        The default implementation of this method returns null. It is expected that most child classes will override this method.
        Parameters:
        iq - The IQ request stanza of type get that was received by this component.
        Returns:
        the response the to request stanza, or null to indicate 'feature-not-available'.
        Throws:
        Exception - if internal error occurs.

      • handleIQSet

        protected IQ handleIQSet​(IQ iq)
                  throws Exception
        Override this method to handle the IQ stanzas of type set that could not be processed by the AbstractComponent implementation.
        Note that, as any IQ stanza of type set must be replied to, returning null from this method equals returning an IQ error stanza of type 'feature-not-implemented' {this behavior can be disabled by setting the enforceIQResult argument in the constructor to false).
        Note that if this method throws an Exception, an IQ stanza of type error, condition 'internal-server-error' will be returned to the sender of the original request.
        The default implementation of this method returns null. It is expected that most child classes will override this method.
        Parameters:
        iq - The IQ request stanza of type set that was received by this component.
        Returns:
        the response the to request stanza, or null to indicate 'feature-not-available'.
        Throws:
        Exception - if internal error occurs.

      • handleDiscoItems

        protected IQ handleDiscoItems​(IQ iq)
        Default handler of Service Discovery Info requests. Unless overridden, this method returns null, which will result into a 'service-unavailable' response to be returned as a response to the original request.
        Parameters:
        iq - The Service Discovery Items
        Returns:
        Service Discovery Items response.

      • handleDiscoInfo

        protected IQ handleDiscoInfo​(IQ iq)
        Default handler of Service Discovery Info requests. Unless overridden, this method returns an IQ result packet that includes:
        • One Service Discovery 'Identity'. The attributes of the identity are determined in this way:
        • A list of Service Discovery 'Features', which consist of the 'Service Discovery Info' feature, and the results of discoInfoFeatureNamespaces().

        Note that you should include the 'Service Discovery Items' feature if handleDiscoInfo(IQ) returns a non-null value.
        Parameters:
        iq - The Service Discovery 'info' request stanza.
        Returns:
        A response to the received Service Discovery 'info' request.

      • handlePing

        protected IQ handlePing​(IQ iq)
        Default handler of Ping requests (XEP-0199). Unless overridden, this method returns an empty result stanza, which is the expected response to a Ping.
        Parameters:
        iq - The Ping request stanza.
        Returns:
        The XMPP way of saying 'pong'.

      • handleLastActivity

        protected IQ handleLastActivity​(IQ iq)
        Default handler of Last Activity requests (XEP-0012). Unless overridden, this method returns a result stanza that specifies how long this component has been running since it was last (re)started.
        Parameters:
        iq - The Last Activity request stanza.
        Returns:
        Last Activity response that reports back the uptime of this component.

      • handleEntityTime

        protected IQ handleEntityTime​(IQ iq)
        Default handler of Entity Time requests (XEP-0202). Unless overridden, this method returns the current local time as specified by the XEP.
        Parameters:
        iq - Entity Time request stanza.
        Returns:
        Result stanza including the local current time.

      • getDescription

        public abstract String getDescription()
        Description copied from interface: Component
        Returns the description of this component.
        Specified by:
        getDescription in interface Component
        Returns:
        the description of this component.

      • getName

        public abstract String getName()
        Description copied from interface: Component
        Returns the name of this component.
        Specified by:
        getName in interface Component
        Returns:
        the name of this component.

      • getDomain

        public String getDomain()
        Returns the XMPP domain to which this component is registered to. To full address of this component should be a subdomain of the domain returned by this method.
        Returns:
        The XMPP domain name, or null if this component has not been initialized yet.

      • getJID

        public JID getJID()
        Returns the XMPP address / Jabber ID (JID) of this component.
        Returns:
        The JID of this component, or null if this component has not been initialized yet.

      • discoInfoIdentityCategory

        protected String discoInfoIdentityCategory()
        Returns the category of the Service Discovery Identity of this component (this implementation will only hold exactly one Identity for the component).
        The default Category of a component, which is used if this method is not overridden, is 'component'.
        Returns:
        the category of the Service Discovery Identity of this component.
        See Also:
        official Service Discovery Identities registry

      • discoInfoIdentityCategoryType

        protected String discoInfoIdentityCategoryType()
        Returns the type of the Service Discovery Identity of this component (this implementation will only hold exactly one Identity for the component).
        The default Category type of a component, which is used if this method is not overridden, is 'generic'.
        Returns:
        the type of the Service Discovery Identity of this component.
        See Also:
        official Service Discovery Identities registry

      • discoInfoFeatureNamespaces

        protected String[] discoInfoFeatureNamespaces()
        This method returns a String array that should contain all namespaces of features that this component offers. The result of this method will be included in Service Discovery responses.
        Note that the features that are returned by this method should also be implemented in either handleIQGet(IQ) and/or handleIQSet(IQ) methods. Also note that the default namespaces for service discovery should not be returned by this method.
        The default implementation of this method returns an empty array. Override this method to include new namespaces.
        Returns:
        Namespaces of all features provided by this Component

      • handleMessage

        protected void handleMessage​(Message message)
        Override this method to handle the Message stanzas that are received by the component. If you do not override this method, the stanzas are ignored.
        Parameters:
        message - The Message stanza that was received by this component.

      • handlePresence

        protected void handlePresence​(Presence presence)
        Override this method to handle the Presence stanzas that are received by the component. If you do not override this method, the stanzas are ignored.
        Parameters:
        presence - The Presence stanza that was received by this component.

      • servesLocalUsersOnly

        public boolean servesLocalUsersOnly()
        Checks if the component can only be used by users of the XMPP domain that the component has registered to. If this method returns true, this will happen:
        • Messages and Presence stanzas are silently ignored.
        • IQ stanza's of type result and error are silently ignored.
        • IQ stanza's of type get or set are responded to with a IQ error response, type 'cancel', condition 'not-allowed'.
        Note that by default, this method returns false. You can override this method to change the behavior.
        Returns:
        true if this component serves local users only, false otherwise.

      • shutdown

        public final void shutdown()
        Default implementation of the shutdown() method of the Component interface.
        Specified by:
        shutdown in interface Component

      • send

        protected void send​(Packet packet)
        Helper method to send packets.
        Parameters:
        packet - The packet to send.

      • preComponentShutdown

        public void preComponentShutdown()
        This method gets called as part of the Component shutdown routine. This method gets called before the other shutdown methods get executed. This enables extending classes to initiate a cleanup before the component gets completely shut down.

      • postComponentShutdown

        public void postComponentShutdown()
        This method gets called as part of the Component shutdown routine. This method gets called after the other shutdown methods got executed. This enables extending classes to finish cleaning up after all other cleanup has been performed.

      • start

        public void start()
        Default implementation of the start() method of the Component interface. Unless overridden, this method doesn't do anything. We get called once for each host that we connect to, so we have to take care to avoid double initialization.
        Specified by:
        start in interface Component

      • preComponentStart

        public void preComponentStart()
        This method gets called as part of the Component 'start' routine. This method gets called before the other 'start' methods get executed. This enables extending classes to initialize resources before the component gets completely started. This method is called once for each host that we connect to, so we have to take care to avoid double initialization.

      • postComponentStart

        public void postComponentStart()
        This method gets called as part of the Component 'start' routine. This method gets called after the other 'start' methods got executed. This enables extending classes to finish initializing resources after all other resources has been initialized. This method is called once for each host that we connect to, so we have to take care to avoid double initialization.