source: source/ariba/overlay/modules/OverlayInterface.h

// [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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// Germany
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// 1. Redistributions of source code must retain the above copyright
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// [License]

#ifndef __OVERLAY_INTERFACE_H
#define __OVERLAY_INTERFACE_H

#include "ariba/CommunicationListener.h"
#include "ariba/communication/EndpointDescriptor.h"
#include "ariba/overlay/modules/OverlayStructureEvents.h"
#include "ariba/utility/types/NodeID.h"
#include "ariba/utility/types/ServiceID.h"
#include "ariba/utility/types/OverlayParameterSet.h"

using ariba::CommunicationListener;
using ariba::communication::EndpointDescriptor;
using ariba::overlay::OverlayStructureEvents;
using ariba::utility::NodeID;
using ariba::utility::ServiceID;
using ariba::utility::OverlayParameterSet;

namespace ariba {
namespace overlay {

class BaseOverlay;

/**
 * This class declares an interface for an structured overlay.
 */
class OverlayInterface: public CommunicationListener {
        friend class BaseOverlay;

public:
        /**
         * A node list
         */
        typedef vector<NodeID> NodeList;

        /**
         * Constructs a new overlay.
         */
        OverlayInterface( BaseOverlay& _baseoverlay, const NodeID& _nodeid,
                OverlayStructureEvents* _eventsReceiver, OverlayParameterSet _parameters
        );

        /**
         * Destructs the overlay.
         */
        virtual ~OverlayInterface();

        /**
         * Creates the overlay.
         */
        virtual void createOverlay() = 0;

        /**
         * Destroys the overlay.
         */
        virtual void deleteOverlay() = 0;

        /**
         * Joins the overlay. Starts integration and stabilization of the overlay
         * Node.
         *
         * @param bootstrap The bootstrap end-point descriptor or the default
         *    end-point, if this node is the initiator
         */
        virtual void joinOverlay(
                const EndpointDescriptor& bootstrap = EndpointDescriptor::UNSPECIFIED()) = 0;

        /**
         * Leaves the overlay gracefully.
         */
        virtual void leaveOverlay() = 0;

        /**
         * Resolves a overlay neighbor.
         *
         * @param node The node to resolve
         * @return Endpoint descriptor of local neighbor or UNSPECIFIED
         */
        virtual const EndpointDescriptor& resolveNode(const NodeID& node) = 0;


        /**
         * Returns true if this is the closest node to the given node
         * identifier.
         *
         * @param node The node identifier to compare with
         * @return True if this is the closest node to the given node identifier
         */
        virtual bool isClosestNodeTo( const NodeID& node ) = 0;

        /**
         * Returns the nodes known to this overlay.
         *
         * Usually this are the direct neighbors in the overlay structure.
         * For instance, Chord would return his predecessor, successor and finger
         * nodes. On the other hand OneHop would likely return all participating
         * nodes in the overlay.
         *
         * @return The list of all known nodes
         */
        virtual NodeList getKnownNodes(bool deep = true) const = 0;

        /**
         * Returns the link id of the next hop a route message would take.
         *
         * @param id The destination node id
         * @return The link id of the next hop
         */
        virtual const LinkID& getNextLinkId( const NodeID& id ) const = 0;

    /**
     * Returns link ids of possible next hops a route message could take,
     * sorted by "quality" (e.g. overlay-distance).
     *
     * The »num« parameter can be used to specify the desired number of elements 
     * in the returned vector. This is intendet for optimizations. The
     * implementation may choose to return a different number of elements than
     * requested.
     * 
     * NOTE: The returned vector may contain »unspecified« links. These refer to 
     * to the own node. (e.g. If there's no closer node, the top element in the 
     * returned vector is unsoecified.)
     * 
     * @param id The destination node id
     * @param num The desired number of elements in the returned vector.
     *            (0 means »not specified/max)«
     * @return A sorted vector of link ids to possible next hops.
     */
    virtual std::vector<const LinkID*> getSortedLinkIdsTowardsNode(
        const NodeID& id, int num = 0 ) const = 0;

        /**
         * Returns the NodeID of the next hop a route message would take.
         * 
         * @param id The destination node id
         * @return The node id of the next hop
         */
        virtual const NodeID& getNextNodeId( const NodeID& id ) const = 0;

        //--- functions from CommunicationListener that we _can_ use as overlay ---

        /// @see CommunicationListener
        virtual void onLinkUp(const LinkID& lnk, const NodeID& remote);

        /// @see CommunicationListener
        virtual void onLinkDown(const LinkID& lnk, const NodeID& remote);

        /// @see CommunicationListener
        virtual void onLinkChanged(const LinkID& lnk, const NodeID& remote);

        /// @see CommunicationListener
        virtual void onLinkFail(const LinkID& lnk, const NodeID& remote);

        /// @see CommunicationListener
        virtual void onLinkQoSChanged(const LinkID& lnk, const NodeID& remote,
                        const LinkProperties& prop);

        /// @see CommunicationListener
        virtual bool onLinkRequest(const NodeID& remote, const DataMessage& msg);

        /// @see CommunicationListener
        virtual void onMessage(OverlayMsg* msg,
                reboost::shared_buffer_t sub_msg,
                const NodeID& remote,
                        const LinkID& lnk = LinkID::UNSPECIFIED);

        const OverlayParameterSet& getParameters() const;

        virtual std::string debugInformation() const;

protected:
        /// Reference to an active base overlay
        BaseOverlay& baseoverlay;

        /// The node identifier to use with this overlay
        const NodeID& nodeid;

        /// The listener used to inform about overlay structure changes
        OverlayStructureEvents* eventsReceiver;

        /// The parameters of the overlay structure
        OverlayParameterSet parameters;

        /// The service identifer of this overlay
        static ServiceID OVERLAY_SERVICE_ID;
};

}} // namespace ariba, overlay

#endif // __OVERLAY_INTERFACE_H