source: source/ariba/Node.h@ 3049

// [License]
// The Ariba-Underlay Copyright
//
// Copyright (c) 2008-2009, Institute of Telematics, UniversitÀt Karlsruhe (TH)
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// UniversitÀt Karlsruhe (TH)
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// [License]

#ifndef NODE_H_
#define NODE_H_

// forward declarations
namespace ariba {
class Node;
}

#include <vector>
#include "Module.h"
#include "Identifiers.h"
#include "SpoVNetProperties.h"
#include "NodeListener.h"
#include "Name.h"
#include "AribaModule.h"
#include "CommunicationListener.h"
#include "DataMessage.h"

using std::vector;

namespace ariba {

// forward declaration
namespace interface {
class ServiceInterface;
}

namespace overlay {
class BaseOverlay;
}

/**
 * This class should implement all ariba node functionality.
 *
 * @author Sebastian Mies <mies@tm.uka.de>
 * @author Christoph Mayer <mayer@tm.uka.de>
 */
class Node: public Module {
public:
        /**
         * Constructs a new node using a given ariba module
         *
         * @param ariba_mod The ariba module
         * @param name The canonical node name of the new node. When NULL a
         *   randomly chosen name is created.
         * @param len The length of the canonical node name or -1, if the name
         *   is a zero-terminated char-string.
         */
        Node(AribaModule& ariba_mod, const Name& node_name = Name::UNSPECIFIED);

        /**
         * Destroys the node. Before destruction some pre-conditions
         * must be met:<br />
         *
         * 1. The node is not part of any SpoVNet <br />
         * 2. All listeners must be unbound from this node <br />
         * 3. The module has been stopped<br />
         */
        ~Node();

        //--- node control ---

        /**
         * This method instructs the node to join a particular spovnet.
         * Callees may bind with a NodeListener to receive events, when
         * a node has been successfully joined.
         *
         * @param vnetId The SpoVNet name
         */
        void join(const Name& name);

        /**
         * This method initiates a new SpoVNet with the given SpoVNetID and
         * parameters.
         *
         * @param name The SpoVNet name
         * @param param The SpoVNet properties
         */
        void initiate(const Name& name, const SpoVNetProperties& parm =
                        SpoVNetProperties::DEFAULT);

        /**
         * This method initiates the leave procedure of this node.
         */
        void leave();

        /**
         * This method is used to bind a node listener to this node.
         *
         * @param listener The node listener
         */
        void bind(NodeListener* listener);

        /**
         * This method is used to unbind a node listener to this node.
         *
         * @param listener The node listener
         */
        void unbind(NodeListener* listener);

        //--- spovnet properties ---

        /**
         * Returns the properties of the spovnet the node has joined.
         *
         * @return The properties of the spovnet the node has joined
         */
        const SpoVNetProperties& getSpoVNetProperties() const;

        /**
         * Returns the spovnet identifier
         *
         * @return The spovnet idenfifier
         */
        const SpoVNetID& getSpoVNetId() const;

        /**
         * Returns true, if the node is part of a spovnet.
         *
         * @return True, if the node is part of a spovnet
         */
        bool isJoined() const;

        //--- addressing ---

        /**
         * Returns the node id of this node if the link id is unspecified or
         * the node id of the remote node.
         *
         * @return The local or the remote node identifier
         */
        const NodeID& getNodeId(const LinkID& lid = LinkID::UNSPECIFIED) const;

        /**
         * Returns the node id to a node name according to the currently joined
         * spovnet (usually derives a node identifier by hashing the name).
         *
         * @return The node identifier to the given name
         */
        NodeID generateNodeId(const Name& name) const;

        /**
         * Returns the name of this node if the link id is unspecified or
         * the node name of the remote node, if known -- otherwise it returns
         * an unspecified name.
         *
         * TODO: RFE -- send request to remote node and inform service.
         *
         * @return A node's name or an unspecified name, if unknown
         */
        const Name getNodeName(const LinkID& lid = LinkID::UNSPECIFIED) const;

        /**
         * Get a list of neighboring nodes in the overlay structure.
         * The number and identities of nodes depends highly on the
         * used overlay structure.
         *
         * @return a list of NodeIDs that are neighbors in the overlay structure
         * @see sendBroadcastMessage
         */
        vector<NodeID> getNeighborNodes() const;

        //--- communication ---

        /**
         * Establishes a new link to another node and service with the given
         * link properties. An optional message could be sent with the request.
         *
         * @param nid The remote node identifier
         * @param sid The remote service identifier
         * @param req The required link properties
         * @param msg An optional message that is sent with the request
         * @return A new link id
         */
        LinkID establishLink(const NodeID& nid, const ServiceID& sid,
                        const LinkProperties& req = LinkProperties::DEFAULT,
                        const DataMessage& msg = DataMessage::UNSPECIFIED);

        /**
         * This method drops an established link.
         *
         * @param lnk The link identifier of an active link
         */
        void dropLink(const LinkID& lnk);

        // message sending

        /**
         * Sends a one-shot message to a service. If link properties are specified,
         * the node tries to fulfill those requirements. This may cause the node
         * to first establish a temporary link, second sending the message and last
         * dropping the link. This would result in a small amount of extra latency
         * until the message is delivered. If reliable transport was selected,
         * the method returns a sequence number and a communication event is
         * triggered on message delivery or loss.
         *
         * @param msg The message to be sent
         * @param nid The remote node identifier
         * @param sid The remote service identifier
         * @param req The requirements associated with the message
         * @return A sequence number
         */
        seqnum_t sendMessage(const DataMessage& msg, const NodeID& nid, const ServiceID& sid,
                        const LinkProperties& req = LinkProperties::DEFAULT);

        /**
         * Sends a message via an established link. If reliable transport was
         * selected, the method returns a sequence number and a communication event
         * is triggered on message delivery or loss.
         *
         * @param msg The message to be sent
         * @param lnk The link to be used for sending the message
         */
        seqnum_t sendMessage(const DataMessage& msg, const LinkID& lnk);

        /**
         * Sends a message to all known hosts in the overlay structure
         * the nodes that are reached here depend on the overlay structure.
         *
         * @param msg The message to be send
         * @param sid The id of the service that should receive the message
         * @see getNeighborNodes
         */
        void sendBroadcastMessage(const DataMessage& msg, const ServiceID& sid);

        // --- communication listeners ---

        /**
         * Binds a listener to a specifed service identifier.
         * Whenever a link is established/dropped or messages are received the
         * events inside the interface are called.
         *
         * @param listener The listener to be registered
         * @param sid The service identifier
         */
        void bind(CommunicationListener* listener, const ServiceID& sid);

        /**
         * Un-binds a listener from this node.
         *
         * @param The listener to be unbound
         */
        void unbind(CommunicationListener* listener, const ServiceID& sid);

        // --- extension proposal: service directory -- TODO
        // main-idea: use this methods to register groups/rendevous points inside
        // the base overlay via a distributed storage service.
        //
        //void put(const KeyID& key, Message* value);
        //void get(const KeyID& key);
        //-------------------------------------------------------------------------
        //
        // --- optimization proposal: allow direct endpoint descriptor exchange ---
        // main-idea: directly allow exchanging endpoint descriptors to establish
        // links. Depending on the overlay structure used in the base overlay, this
        // allows a node to directly establish links between two nodes when an
        // endpoint descriptor is known.
        //
        //const EndpointDescriptor& getEndpointDescriptor( const LinkID& lid );
        //void sendMessage( EndpointDescriptor& epd, Message* msg );
        //LinkID setupLink( const EndpointDescriptor& endpointDesc,
        //              const LinkProperties& req = LinkProperties::UNSPECIFIED,
        //              const Message* msg = NULL );
        //
        //-------------------------------------------------------------------------

        // --- module implementation ---
        //
        // main-idea: use module properties to configure nodeid, spovnetid etc. and
        // select start/stop procedures. This allows simulations to start a
        // node without manually calling join etc.

        /** @see Module.h */
        void initialize();

        /** @see Module.h */
        void start();

        /** @see Module.h */
        void stop();

        /** @see Module.h */
        string getName() const;

        /** @see Module.h */
        void setProperty(string key, string value);

        /** @see Module.h */
        const string getProperty(string key) const;

        /** @see Module.h */
        const vector<string> getProperties() const;

protected:
        // friends
        friend class AribaModule;

        // member variables
        Name name;                             //< node name
        AribaModule& ariba_mod;                //< ariba module
        SpoVNetID spovnetId;                   //< current spovnet id
        NodeID nodeId;                             //< current node id
        overlay::BaseOverlay* base_overlay;    //< the base overlay

        // delegates
        static ServiceID anonymousService;
};

} // namespace ariba

#endif /* NODE_H_ */