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#ifndef RESOURCE_SET_H
#define RESOURCE_SET_H

#include <policy/resources.h>
#include <QString>
#include <QObject>
#include <QVector>
#include <QList>

/**
 * \mainpage Resource Policy Library
 * 
 * \section intro_section Introduction
 * 
 * This library is used to request resources from the Polict Resource Manager.
 * To use this library two classes are provided: \ref ResourcePolicy::Resource and
 * \ref ResourcePolicy::ResourceSet.
 * 
 * \section library_use_section Library Usage
 * 
 * To use the Resource Policy Library, you first need to create a number of
 * \ref Resource objects like this (given as an example of what a media player
 * might want/need):
 * \code
 * ResourcePolicy::AudioResource *audioResource = new ResourcePolicy::AudioResource();
 * ResourcePolicy::VideoResource *audioResource = new ResourcePolicy::VideoResource();
 * videoResource->setOptional();
 * \endcode
 * Then you need to create a \ref ResourcePolicy::ResourceSet like this:
 * \code
 * ResourcePolicy::ResourceSet *resources = new ResourcePolicy::ResourceSet("player");
 * resources->addResource(audioResource);
 * resources->addResource(videoResource);
 * resources->initialize();
 * QObject::connect(resources, SIGNAL(connectedToManager()), this, SLOT(connectedHandler()));
 * resources->connectToManager();
 * \endcode
 * Then the when you want to acquire the \ref ResourcePolicy::ResourceSet you simply use the
 * \ref acquire() method of the \ref ResourceSet object, like this:
 * \code
 * QObject::connect(resources, SIGNAL(resourcesAcquired),
 *                  this, SLOT(acquireOkHandler(QList<ResourcePolicy::Resource>)));
 * QObject::connect(resources, SIGNAL(resourcesDenied), this, SLOT(acquireDeniedHandler()));
 * resources->acquire();
 * \endcode
 */

/**
 * The Namespace for Resource Policy.
 */
namespace ResourcePolicy
{
    /**
     * The resourceSet repesents a set of attributes. Each set can only contain
     * a single Resource of a given type. That is one AudioPlaybackResource, etc.
     *
     * Internally the set is stored as a QVector of \ref Resource objects.
     */
    class ResourceSet: public QObject
    {
        Q_OBJECT
        Q_DISABLE_COPY( ResourceSet )
    public:
        /**
         * The constructor.
         * \param applicationClass This parameter defines the application class.
         * The application class is used to determine the priority order of the
         * application.
         * \param parent The optional parent of of this class.
         */
        ResourceSet(const QString &applicationClass, QObject *parent=NULL);
        /**
         * The destructor
         */
        ~ResourceSet();
        /**
         * Finalizes the ResourceSet. This method should be called after all
         * resources have been added to the set.
         * \return true if the finalization was successful.
         */
        bool finalize();

        /**
         * This method adds a resource to the set. A set contains only a single
         * instance of a given resource. If the ResourceSet already contains a
         * resource of the given type it will be overridden.
         * \param resource The resource to add to the set. A copy of this object
         * is stored in the Set.
         */
        void addResource(const Resource *resource);
        /**
         * This method adds all resources in the list to the set.
         * A set contains only a single instance of a given resource. If the
         * ResourceSet already contains a resource of the given type it will be
         * overridden.
         * \param resources The list of resources to add to the set. These will
         * be copied.
         */
        void addResources(const QList<Resource *>resources);
        /**
         * This method removes the resource of the given type
         * \param type The type of the resource to remove from the set.
         */
        void delResource(ResourceType type);

        /**
         * This method returns a list of all resource in the set.
         * \return a QList of all resources in the set.
         */
        QList<Resource *> resources() const;
        /**
         * This method returns a const pointer to a resource of a specific type.
         * \type The type of resource we are interested in.
         * \return a pointer to the Resource if it is defined NULL otherwise.
         */
        Resource * resource(ResourceType type) const;
        /**
         * Checks if the \ref ResourceSet contains the given \ref Resource
         * \param type The Resource to look for
         * \return true if the \ref Resource is defined in this \ref ResourceSet
         */
        bool contains(ResourceType type) const;

        /**
         * Checks if the \ref ResourceSet contains all given resources.
         * \param types A list of resources to check for
         * \return true if \b all given resources are defined in the ResourceSet.
         */
        bool contains(const QList<ResourceType> &types) const;

        /**
         * Returns the unique identifier for this ResourceSet.
         * @return the unique identifier for this ResourceSet.
         */
        quint32 id() const;

        /**
         * Returns the registered application class (given in the constructor).
         */
        QString applicationClass();

        /**
         * Try to acquire the \ref ResourceSet. The resourcesGranted() or
         * resourcesDenied() signal will be emited depending on whether the
         * requested resources could be acquired or not.
         */
        bool acquire();
        /**
         * Release the acquired resources.
         */
        bool release();
        /**
         * Commit changes to the \ref ResourceSet. Remember to call update()
         * after adding and/or removing resources.
         */
        bool update();

        /**
         * Stes the auto-release. When loosing the resources doue to another
         * application with a higher priority the default is that we automatically 
         * re-gain our resources without having to re-request them. However if
         * the AutoRelease is set we release the resources and need to re-acquire
         * them, when the pre-emting application releases it s resources.
         * This feature is by default disabled.
         * Remember to call update() when changing this.
         */
        void setAutoRelease();
        /**
         * see \ref setAutoRelease().
         */
        void unsetAutoRelease();
        /**
         * Sets that the resourcesGranted() signal is emited even if we already 
         * have the requested resources granted. By default this feature is off.
         */
        void setAlwaysReply();
        /**
         * Unsets the always reply flag (see \ref setAlwaysReply())
         */
        void unsetAlwaysReply();

    signals:
        /**
         * This signal is emited when the Resource Policy Manager notifies that
         * the given resources have become available.
         * \param availableResources A list of available resources. The list of
         * available resources contains only available resource which we have in the set.
         */
        void resourcesBecameAvailable(QList<ResourceType> availableResources);
        /**
         * This signal is emited as a response to the acquire() request.
         * \param grantedOptionalResources The list of granted optional resources.
         * All the mandatory resources have also been aquired.
         */
        void resourcesGranted(QList<ResourceType> grantedOptionalResources);
        /**
         * This signal is emited as a response to the acquire() request, in the
         * case where one or more of the mandatroy resources were not availalble.
         */
        void resourcesDenied();
        /**
         * This signal is emited when some other program with a higher priority
         * superseeds us, and as a result we loose our resources.
         */
        void lostResources();

    private:
        quint32 identifier;
        const QString resourceClass;
        Resource* resourceSet[NumberOfTypes];
        bool connected;
        bool autoRelease;
        bool alwaysReply;
    };
}

#endif