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module com { module sun { module star { module drawing { module framework {

interface XConfigurationChangeListener;
interface XConfigurationChangeRequest;
interface XResourceId;
interface XResource;

/** The configuration controller is responsible for the management of the
    set of active resources.

    <p>There are two configurations of resources:<ul>
    <li>The current configuration contains the set of currently active
    resources.</li>
    <li>The requested configuration describes what the current configuration
    should be.  The requested configuration is changed usually by calling
    requestResourceActivation() and
    requestResourceDeactivation().</li>
    </ul></p>

    <p>When the two configurations differ then the current configuration is
    updated eventually to reflect the requested configuration.  An update
    takes place when the following three conditions are fulfilled.
    <ol>
    <li>when the last pending request for configuration changes has been
    processed,</li>
    <li>when the update() method is called.</li>
    <li>when the configuration manager it is unlocked after formerly being
    locked.</li>
    </ol></p>

    <p>Requests for configuration changes are handled in a two step process:
    <ol>
    <li>First the requested configuration is updated iteratively: Every
    request that is being made by calling
    requestResourceActivation() or
    requestResourceDeactivation() results in one or more
    function objects, that each implement the
    XConfigurationChangeRequest interface.  These are inserted
    into a queue.  The request objects in the queue are processed
    asynchronously one at a time in the order in which they are inserted.
    Only when one request object is processed a change to the requested
    configuration is made.  These changes are broadcasted to registered
    XConfigurationChangeListener objects.  Listeners may
    decide to make requests that then are added to the queue.  For example
    when the view in the center pane is replaced by another view, some
    listeners may want to turn some side panes on or off, or show other
    views in the side panes.</p>
    <p>This process goes on until the queue of request objects becomes
    empty.  Until this point only the requested configuration has been
    modified.  No resources have been activated or deactivated.</p></li>

    <li><p>The second update step activates or deactivates resources so that
    the current configuration (the one that comprises the actually active
    resources) reflects the requested configuration.</p>
    <p>The order in which resources are activated or deactivated depends on
    the dependency between the resources.  For example a view depends on the
    pane it is displayed in.  Resources that other resources depend on are
    activated first and deactivated last.  The order is undefined for
    unrelated resources.</p>
    <p>Note that the second update step may not be able to activate (or even to
    deactivate) all the requested resources.  Either because they are
    temporarily or permanently unavailable.  For example, during the
    start-up of a new Impress application the side panes are displayed
    with a visible delay because they are not provided sooner by the
    underlying framework.  Such unavailable resources are not forgotten but
    remain in the requested configuration.  Every time the configuration
    controller updates its current configuration these resources are
    requested once more.</li></ol></p>

    <p>The configuration controller sends the following events:
    <ul>
    <li>ResourceActivationRequested is sent when the
    activation of a resource has been requested and the resource is not yet
    active in the requested configuration.  The event is sent when the
    configuration change request is executed, not when the
    requestResourceActivation() call is made.</p>
    <p>The ConfigurationChangeEvent::ResourceId member is set to the requested
    resource.  The ResourceObject member is not
    set.</p></li>
    <li>ResourceDeactivationRequested is sent when the
    deactivation of a resource has been requested and the resource is active
    in the requested configuration.  The event is sent when the
    configuration change request is executed that is created when for
    example requestResourceDeactivation() is called.</p>
    <p>The ResourceId member is set to the requested
    resource.  The ResourceObject member is not
    set.</p></li>
    <li>ConfigurationUpdateStart is sent before the update of
    the current configuration starts.</p>
    <p>The requested configuration is available in the
    ConfigurationChangeEvent::Configuration member.  The
    ResourceId and ResourceObject members
    are not set.</p></li>
    <li>ConfigurationUpdateEnd is sent after the update of
    the current configuration ends.</p>
    <p>The requested configuration is
    available in the ConfigurationChangeEvent::Configuration member.
    The ResourceId and ResourceObject members are not set.</p></li>
    <li>ResourceActivation is sent when a resource is
    activated, i.e. when a new object of a resource is created (or taken
    from a cache).</p>
    <p>The ResourceId and ResourceObject
    members are set to the XResourceId and object reference of
    the activated resource.</p></li>
    <li>ResourceDeactivation is sent when a resource is
    deactivated, i.e. when an object that previously was part of the
    configuration is removed from the configuration.</p>
    <p>The ResourceId and ResourceObject
    members are set to XResourceId and object reference of the
    deactivated resource.</p></li>
    </ul></p>
*/
interface XConfigurationController
{
    interface XConfigurationControllerRequestQueue;
    interface XConfigurationControllerBroadcaster;
    interface XResourceFactoryManager;

    /** Request the activation of a resource.
        <p>The request is processed asynchronously.  Notifications about
        configuration changes are sent after this call returns.</p>
        @param xResourceId
            The resource whose activation is requested.
        @param eMode
            <p>When eMode is REPLACE then, before adding the
            resource activation to the request queue, similar resources
            linked to the same anchor are removed.  This makes it easier to
            switch between resources whose activation is mutually exclusive.
            For example, there can only be one view per pane, so before
            activating a new view the old one has to be deactivated.</p>
            <p>When eMode is ADD then the resource is requested
            without further changes.</p>
    */
    void requestResourceActivation (
        [in] XResourceId xResourceId,
        [in] ResourceActivationMode eMode);

    /** Request the deactivation of a resource.
        <p>The request is processed asynchronously.  Notifications about
        configuration changes are sent after this call returns.</p>
        <p>Requesting the deactivation
        of a resource that is not active is not an error.</p>
        @param xResourceId
            The resource whose deactivation is requested.
    */
    void requestResourceDeactivation (
        [in] XResourceId xResourceId);


    /** Return the active resource specified by the given resource id.
        @param xResourceId
            A valid resource id.  This should, but does not have to be, the
            resource id of an active resource.
        @return
            When the given resource id specifies an active resource then
            that resource is returned.  Otherwise an empty reference is
            returned.
    */
    XResource getResource (
        [in] XResourceId xResourceId);

    /** Lock the processing of configuration change requests.
        <p>This is only necessary when more than one change request is being
        made in a row.  It prevents an update being made (with all the visible UI
        changes) before all change requests are being made.</p>
        <p>Recursive lock() calls are recognized: the
        configuration controller is locked while lock() was
        called more often than unlock().</p>
    */
    void lock ();

    /** Unlock the processing of configuration change requests.
        <p>When unlock() is called as many times as
        lock() and the queue of configuration change
        requests is not empty the configuration controller continues the
        processing of the change requests.  An update of the current
        configuration will eventually being made.</p>
    */
    void unlock ();

    /** Explicitly request an update of the current configuration.
        <p>Call it when a resource is activated or deactivated
        without the control and knowledge of the drawing framework.  Calling
        this method (from outside the drawing framework) should hardly every
        be necessary.</p>
    */
    void update ();

    /** Return a copy of the requested configuration.
        <p>Modifications to the returned configuration have no effect on the
        drawing framework.</p>
    */
    XConfiguration getRequestedConfiguration ();

    /** Return a copy of the current configuration.
        <p>Modifications to the returned configuration have no effect on the
        drawing framework.</p>
    */
    XConfiguration getCurrentConfiguration ();

    /** Replace the requested configuration with the given configuration and
        schedule an update of the current configuration.
        <p>Together with the getCurrentConfiguration() and
        getRequestedConfiguration() methods this
        allows the saving and restoring of configurations.  However, the
        given configuration can have other origins then these methods.</p>
        <p>The given configuration is transformed into a list of change
        requests so that the resulting requested configuration equals the
        given configuration.  This has the advantage that not only the
        resource activations and deactivations but all configuration
        changes are properly broadcasted.</p>
        <p>Note that because of the configuration change notifications
        listeners can make more configuration change requests, so that the
        resulting requested configuration can be different from the given
        configuration.</p>
        @param xConfiguration
            This typically is a configuration that was obtained with an
            earlier getRequestedConfiguration() call.
    */
    void restoreConfiguration ([in] XConfiguration xConfiguration);
};

}; }; }; }; }; // ::com::sun::star::drawing::framework

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