Package jade.proto

Class SubscriptionInitiator

  • All Implemented Interfaces:
    Serializable, Serializable
    Direct Known Subclasses:
    DFSubscriber
    public class SubscriptionInitiator
extends FSMBehaviour
    This is a single homogeneous and effective implementation of the initiator role in all the FIPA-Subscribe-like interaction protocols defined by FIPA, that is all those protocols where the initiator sends a single "subscription" message and receives notifications each time a given condition becomes true. This implementation works both for 1:1 and 1:N conversations.

    FIPA has already specified a number of these interaction protocols, like FIPA-subscribe and FIPA-request-whenever.

    The structure of these protocols is always the same. The initiator sends a "subscription" message (in general it performs a communicative act).

    The responder can then reply by sending a not-understood, a refuse or an agree message to communicate that the subscription has been agreed. This first category of reply messages has been here identified as a "response". Sending no response is allowed and is equivalent to sending an agree.

    Each time the condition indicated within the subscription message becomes true, the responder sends proper "notification" messages to the initiator.

    This behaviour terminates if a) neither a response nor a notification has been received before the timeout set by the reply-by of the subscription message has expired or b) all responders replied with REFUSE or NOT_UNDERSTOOD. Otherwise the behaviour will run forever.

    NOTE that this implementation is in an experimental state and the API will possibly change in next versions also taking into account that the FIPA specifications related to subscribe-like protocols are not yet stable.

    Read carefully the section of the JADE programmer's guide that describes the usage of this class.
    One message for every receiver is sent instead of a single message for all the receivers.

    Author:
    Giovanni Caire - TILab
    See Also:
    Serialized Form

    • Field Detail

      • SUBSCRIPTION_KEY

        public final String SUBSCRIPTION_KEY
        key to retrieve from the DataStore of the behaviour the subscription ACLMessage object passed in the constructor of the class.

      • ALL_SUBSCRIPTIONS_KEY

        public final String ALL_SUBSCRIPTIONS_KEY
        key to retrieve from the DataStore of the behaviour the vector of subscription ACLMessage objects that have been sent.

      • REPLY_KEY

        public final String REPLY_KEY
        key to retrieve from the DataStore of the behaviour the last ACLMessage object that has been received (null if the timeout expired).

      • ALL_RESPONSES_KEY

        public final String ALL_RESPONSES_KEY
        key to retrieve from the DataStore of the behaviour the vector of ACLMessage objects that have been received as responses.

      • INITIATION_K

        protected final String INITIATION_K

      • ALL_INITIATIONS_K

        protected final String ALL_INITIATIONS_K

      • REPLY_K

        protected final String REPLY_K

      • sessions

        protected Map sessions

    • Constructor Detail

      • SubscriptionInitiator

        public SubscriptionInitiator​(Agent a,
                             ACLMessage msg,
                             DataStore store)
        Construct a SubscriptionInitiator with a given DataStore
        Parameters:
        a - The agent performing the protocol
        msg - The message that must be used to initiate the protocol. Notice that the default implementation of the prepareSubscription() method returns an array composed of only this message. The values of the slot reply-with is ignored and a different value is assigned automatically by this class for each receiver.
        store - The DataStore that will be used by this SubscriptionInitiator

    • Method Detail

      • prepareInitiations

        protected Vector prepareInitiations​(ACLMessage initiation)
        This method is called internally by the framework and is not intended to be called by the user

      • checkInSequence

        protected boolean checkInSequence​(ACLMessage reply)
        Check whether a reply is in-sequence and update the appropriate Session. This method is called internally by the framework and is not intended to be called by the user

      • checkSessions

        protected int checkSessions​(ACLMessage reply)
        Check the status of the sessions after the reception of the last reply or the expiration of the timeout. This method is called internally by the framework and is not intended to be called by the user

      • getToBeReset

        protected String[] getToBeReset()
        Return the states that must be reset before they are visited again. Note that resetting a state before visiting it again is required only if - The onStart() method is redefined - The state has an "internal memory"

      • prepareSubscriptions

        protected Vector prepareSubscriptions​(ACLMessage subscription)
        This method must return the vector of subscription ACLMessage objects to be sent. It is called in the first state of this protocol. This default implementation just returns the ACLMessage object passed in the constructor. Programmers might prefer to override this method in order to return a vector of objects for 1:N conversations or also to prepare the messages during the execution of the behaviour.
        Parameters:
        subscription - the ACLMessage object passed in the constructor
        Returns:
        a Vector of ACLMessage objects. The values of the slot reply-with is ignored and a different value is assigned automatically by this class for each receiver.

      • handleAgree

        protected void handleAgree​(ACLMessage agree)
        This method is called every time an agree message is received, which is not out-of-sequence according to the protocol rules. This default implementation does nothing; programmers might wish to override the method in case they need to react to this event.
        Parameters:
        agree - the received agree message

      • handleRefuse

        protected void handleRefuse​(ACLMessage refuse)
        This method is called every time a refuse message is received, which is not out-of-sequence according to the protocol rules. This default implementation does nothing; programmers might wish to override the method in case they need to react to this event.
        Parameters:
        refuse - the received refuse message

      • handleInform

        protected void handleInform​(ACLMessage inform)
        This method is called every time a inform message is received, which is not out-of-sequence according to the protocol rules. This default implementation does nothing; programmers might wish to override the method in case they need to react to this event.
        Parameters:
        inform - the received inform message

      • handleAllResponses

        protected void handleAllResponses​(Vector responses)
        This method is called when all the responses have been collected or when the timeout is expired. The used timeout is the minimum value of the slot replyBy of all the sent messages. By response message we intend here all the agree, not-understood, refuse, failure received messages, which are not out-of-sequence according to the protocol rules. This default implementation does nothing; programmers might wish to override the method in case they need to react to this event by analysing all the messages in just one call.
        Parameters:
        responses - the Vector of ACLMessage objects that have been received

      • registerPrepareSubscriptions

        public void registerPrepareSubscriptions​(Behaviour b)
        This method allows to register a user defined Behaviour in the PREPARE_SUBSCRIPTIONS state. This behaviour would override the homonymous method. This method also sets the data store of the registered Behaviour to the DataStore of this current behaviour. It is responsibility of the registered behaviour to put the Vector of ACLMessage objects to be sent into the datastore at the ALL_SUBSCRIPTIONS_KEY key. The values of the slot reply-with is ignored and a different value is assigned automatically by this class for each receiver.
        Parameters:
        b - the Behaviour that will handle this state

      • registerHandleAgree

        public void registerHandleAgree​(Behaviour b)
        This method allows to register a user defined Behaviour in the HANDLE_AGREE state. This behaviour would override the homonymous method. This method also sets the data store of the registered Behaviour to the DataStore of this current behaviour. The registered behaviour can retrieve the agree ACLMessage object received from the datastore at the REPLY_KEY key.
        Parameters:
        b - the Behaviour that will handle this state

      • registerHandleInform

        public void registerHandleInform​(Behaviour b)
        This method allows to register a user defined Behaviour in the HANDLE_INFORM state. This behaviour would override the homonymous method. This method also set the data store of the registered Behaviour to the DataStore of this current behaviour. The registered behaviour can retrieve the inform ACLMessage object received from the datastore at the REPLY_KEY key.
        Parameters:
        b - the Behaviour that will handle this state

      • registerHandleRefuse

        public void registerHandleRefuse​(Behaviour b)
        This method allows to register a user defined Behaviour in the HANDLE_REFUSE state. This behaviour would override the homonymous method. This method also set the data store of the registered Behaviour to the DataStore of this current behaviour. The registered behaviour can retrieve the refuse ACLMessage object received from the datastore at the REPLY_KEY key.
        Parameters:
        b - the Behaviour that will handle this state

      • registerHandleAllResponses

        public void registerHandleAllResponses​(Behaviour b)
        This method allows to register a user defined Behaviour in the HANDLE_ALL_RESPONSES state. This behaviour would override the homonymous method. This method also sets the data store of the registered Behaviour to the DataStore of this current behaviour. The registered behaviour can retrieve the vector of ACLMessage objects, received as a response, from the datastore at the ALL_RESPONSES_KEY key.
        Parameters:
        b - the Behaviour that will handle this state

      • cancel

        public void cancel​(AID receiver,
                   boolean ignoreResponse)
        Cancel the subscription to agent receiver. This method retrieves the subscription message sent to receiver and sends a suitable CANCEL message with the conversationID and all other protocol fields appropriately set. The :content slot of this CANCEL message is filled in by means of the fillCancelContent() method. The way the CANCEL content is set in fact is application specific.
        Parameters:
        receiver - The agent to whom we are cancelling the subscription.
        ignoreResponse - When receiving a CANCEL, the responder may send back a response to notify that the subscription has been cancelled (INFORM) or not (FAILURE). If this parameter is set to true this response is ignored and the session with agent receiver is immediately terminated. When ignoreResponse is set to false, on the other hand, the session with agent receiver remains active and the INFORM or FAILURE massage (if any) will be handled by the HANDLE_INFORM and HANDLE_FAILURE states as if they were normal notifications. It is responsibility of the programmer to distinguish them and actually terminate the session with agent receiver by calling the cancellationCompleted() method.
        See Also:
        fillCancelContent(ACLMessage, ACLMessage), cancellationCompleted(AID)

      • fillCancelContent

        protected void fillCancelContent​(ACLMessage subscription,
                                 ACLMessage cancel)
        This method is used to fill the :content slot of the CANCEL message that is being sent to an agent to cancel the subscription previously activated by means of the subscription message. Note that all other relevant fields of the cancel message have already been set appropriately and the programmer should not modify them. The default implementation just sets a null content (the responder should be able to identify the subscription that has to be cancelled on the basis of the sender and conversationID fields of the CANCEL message). Programmers may override this method to create an appropriate content as exemplified in the code below. 
                 try {
         AID receiver = (AID) cancel.getAllReceiver().next();
         Action a = new Action(receiver, OntoACLMessage.wrap(subscription));
         getContentManager.fillContent(cancel, a);
         }
         catch (Exception e) {
         e.printStackTrace();
         }
        See Also:
        cancel(AID, boolean)

      • cancellationCompleted

        public void cancellationCompleted​(AID receiver)
        This method should be called when the notification of a successful subscription cancellation is received from agent receiver to terminate the session with him. This method has some effect only if a cancellation for agent receiver was previously activated by means of the cancel() method.
        See Also:
        cancel(AID, boolean)

      • reinit

        protected void reinit()
        Re-initialize the internal state without performing a complete reset.

      • initializeDataStore

        protected void initializeDataStore​(ACLMessage msg)
        Initialize the data store. This method is called internally by the framework and is not intended to be called by the user

      • getSession

        protected jade.proto.Initiator.ProtocolSession getSession​(ACLMessage msg,
                                                          int sessionIndex)
        Return a ProtocolSession object to manage replies to a given initiation message

      • sendInitiations

        protected void sendInitiations​(Vector initiations)
        Create and initialize the Sessions and sends the initiation messages

      • handleNotUnderstood

        protected void handleNotUnderstood​(ACLMessage notUnderstood)
        This method is called every time a not-understood message is received, which is not out-of-sequence according to the protocol rules. This default implementation does nothing; programmers might wish to override the method in case they need to react to this event.
        Parameters:
        notUnderstood - the received not-understood message

      • handleFailure

        protected void handleFailure​(ACLMessage failure)
        This method is called every time a failure message is received, which is not out-of-sequence according to the protocol rules. This default implementation does nothing; programmers might wish to override the method in case they need to react to this event.
        Parameters:
        failure - the received failure message

      • handleOutOfSequence

        protected void handleOutOfSequence​(ACLMessage msg)
        This method is called every time a message is received, which is out-of-sequence according to the protocol rules. This default implementation does nothing; programmers might wish to override the method in case they need to react to this event.
        Parameters:
        msg - the received message

      • registerPrepareInitiations

        protected void registerPrepareInitiations​(Behaviour b)
        Attach a behaviour to the Prepare-initiations protocol state.
        Parameters:
        b - The behaviour object to be executed in the Prepare-initiations state.

      • registerHandleNotUnderstood

        public void registerHandleNotUnderstood​(Behaviour b)
        This method allows to register a user defined Behaviour in the HANDLE_NOT_UNDERSTOOD state. This behaviour would override the homonymous method. This method also set the data store of the registered Behaviour to the DataStore of this current behaviour. The registered behaviour can retrieve the not-understood ACLMessage object received from the datastore at the REPLY_KEY key.
        Parameters:
        b - the Behaviour that will handle this state

      • registerHandleFailure

        public void registerHandleFailure​(Behaviour b)
        This method allows to register a user defined Behaviour in the HANDLE_FAILURE state. This behaviour would override the homonymous method. This method also set the data store of the registered Behaviour to the DataStore of this current behaviour. The registered behaviour can retrieve the failure ACLMessage object received from the datastore at the REPLY_KEY key.
        Parameters:
        b - the Behaviour that will handle this state

      • registerHandleOutOfSequence

        public void registerHandleOutOfSequence​(Behaviour b)
        This method allows to register a user defined Behaviour in the HANDLE_OUT_OF_SEQ state. This behaviour would override the homonymous method. This method also set the data store of the registered Behaviour to the DataStore of this current behaviour. The registered behaviour can retrieve the out of sequence ACLMessage object received from the datastore at the REPLY_KEY key.
        Parameters:
        b - the Behaviour that will handle this state

      • reset

        public void reset()
        reset this behaviour by putting a null ACLMessage as message to be sent
        Overrides:
        reset in class FSMBehaviour

      • reset

        public void reset​(ACLMessage msg)
        reset this behaviour
        Parameters:
        msg - is the ACLMessage to be sent

      • onStart

        public void onStart()
        Override the onStart() method to initialize the vectors that will keep all the replies in the data store.
        Overrides:
        onStart in class Behaviour

      • setDataStore

        public void setDataStore​(DataStore ds)
        Override the setDataStore() method to propagate this setting to all children.
        Overrides:
        setDataStore in class Behaviour
        Parameters:
        ds - the DataStore that this Behaviour will use as its private data store

      • createConvId

        protected String createConvId​(Vector msgs)
        Create a new conversation identifier to begin a new interaction.
        Parameters:
        msgs - A vector of ACL messages. If the first one has a non-empty :conversation-id slot, its value is used, else a new conversation identifier is generated.

      • adjustReplyTemplate

        protected void adjustReplyTemplate​(ACLMessage msg)