/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */


module com { module sun { module star { module configuration {

/** provides read access to a fragment of the configuration hierarchy.

 <p>Values that are direct or indirect descendants of a root element can be
 retrieved and, if themselves objects, navigated. Other interfaces provide
 access to information about this element and its context.
 Changes to values in the hierarchy can be monitored by event listeners.
 </p>

 <p>Descendants of this service also implement this service.
 </p>

 <p>Ultimately the configuration holds values. These values are organized into
 a hierarchy using structural elements. The structure is defined in advance in
 a schema. Necessary information from the schema is stored in the configuration
 repository itself and is accessible through an implementation of this service.
 </p>

 <p>Two different kinds of structural elements are used in the configuration
 hierarchy:
 </p>
 <dl>
    <dt>Sets</dt>
        <dd>are dynamic containers of homogeneous elements. Which elements
        a <em>set</em> contains can vary. Their names are defined by the
        clients that insert them. On the other hand, the <em>type</em> of
        the elements is the same for all elements. In the case of elements
        that are themselves hierarchy objects, the <em>type</em> includes
        the structure of the hierarchy fragment they contain. Such types
        are defined in the configuration schema as <em>templates</em>.
        </dd>

    <dt>Groups</dt>
        <dd>are static collections of heterogeneous elements. The names and
        types of the elements of a <em>group</em> are completely defined in the
        configuration schema. Here each element may be of a different
        <em>type</em>, allowing <em>groups</em> that contain a mix of
        subobjects and simple values.
        </dd>
 </dl>

 <p>Objects in the configuration hierarchy, for example, implementations of this service,
 can thus be classified in the following ways:
 </p>
 <ul>
    <li><em>Container</em> role:
        An object that can hold child elements as a <em>set</em> or a <em>group</em>.
    </li>
    <li><em>Element</em> role:
        An object may be an element of a <em>set</em> or a <em>group</em>
        or else it may be the root element.
    </li>
 </ul>

 <p>Several types of simple <em>values</em> can be used in the configuration.
 In addition to the basic (scalar) types, sequences of the basic types are
 supported. The basic types are:
 </p>

 <ul>
    <li><strong>string</strong> can hold a human-readable text.
        <p>Values are represented as `string`.</p>
        <p>Sequences are represented as `string[]`.</p>
        <p>"<em>human-readable</em>" here excludes non-printing characters
        except for CR, LF and TAB [Unicode code points 9,10,13].
        For binary data, use type <strong>binary</strong> instead.</p>
    </li>
    <li><strong>boolean</strong> can hold the values `TRUE` or `FALSE`.
        <p>Values are represented as `boolean`.
        <p>Sequences are represented as `boolean[]`.</p>
    </li>
    <li><strong>short</strong> can hold a 16-bit signed integer.
        <p>Values are represented as `short`.</p>
        <p>Sequences are represented as `short[]`.</p>
    </li>
    <li><strong>int</strong> can hold a 32-bit signed integer.
        <p>Values are represented as `long`.</p>
        <p>Sequences are represented as `long[]`.</p>
    </li>
    <li><strong>long</strong> can hold a 64-bit signed integer.
        <p>Values are represented as `hyper`.</p>
        <p>Sequences are represented as `hyper[]`.</p>
    </li>
    <li><strong>double</strong> can hold a floating point number.
        <p>Values are represented as `double`.</p>
        <p>Sequences are represented as `double[]`.</p>
    </li>
    <li><strong>binary</strong> can hold a sequence of octets.
        <p>Values are represented as `byte[]`.</p>
        <p>Sequences are represented as `byte[][]`.</p>
    </li>
 </ul>

 <p>Within templates an additional type <strong>any</strong> can occur. When
 such a template is used to create a new SetElement, the type
 of the element is initially reported as `any` (having no value).
 When the value of such an element is first set, it will assume the type used.
 </p>

 <p>If the schema marks a value as <em>nullable</em> (which is indicated by
 attribute com::sun::star::beans::PropertyAttribute::MAYBEVOID ),
 its contents may be `NULL`.
 </p>

 <p>The configuration should support explicit access to default values
 (implementing com::sun::star::beans::XPropertyState
 and  com::sun::star::beans::XPropertyWithState).
 </p>

 @see ConfigurationProvider
    Root instances of this service can be requested from a
    ConfigurationProvider.

 @see ConfigurationUpdateAccess
    an extended service that includes facilities for modifying
    configuration data.
*/
published service ConfigurationAccess
{
    /** provides interfaces to access child and descendent elements.

     <p>An implementation actually implements a specialization of this service,
     which depends on its <em>Container</em> role.
     </p>

     <p>Implementations shall implement exactly one of:</p>
     <ul>
        <li>SetAccess if this element is a <em>Set</em>.</li>
        <li>GroupAccess if this element is a <em>Group</em>.</li>
     </ul>
     */
    service HierarchyAccess;

    /** provides interfaces to obtain information about this element and its
     role and context in the hierarchy.

     <p>An implementation actually implements a specialization of this service,
     which depends on its <em>Element</em> role.
     </p>

     <p>Implementations shall implement exactly one of:</p>
     <ul>
        <li>AccessRootElement if this element is the
            <em>Root</em> of the whole hierarchy. Objects that can be
            created directly by a ConfigurationProvider
            implement this service.</li>
        <li>SetElement if this element may be contained in a
            <em>Set</em>.</li>
        <li>GroupElement if this element is a child of a
            <em>Group</em>.</li>
     </ul>

     */
    service HierarchyElement;

    /** specializes HierarchyAccess, if this element is a <em>Set</em>.

         <p>This is an alternative to GroupAccess.
        </p>
    */
    [optional] service SetAccess;

    /** specializes HierarchyAccess,
     if this element is a <em>Group</em>.
     <p>This is an alternative to SetAccess.
     </p>
    */
    [optional] service GroupAccess;

    /** specializes HierarchyElement,
     if this element is the <em>Root</em> of the whole hierarchy.
     <p>This is an alternative to SetElement
     or GroupElement.
     </p>

     @see ConfigurationProvider
        Instances obtained from a ConfigurationProvider will
        implement this version of HierarchyElement.
    */
    [optional] service AccessRootElement;

    /** specializes HierarchyElement,
     if this element may be contained in a <em>Set</em>.
     <p>This is an alternative to AccessRootElement
     or GroupElement.
     </p>
    */
    [optional] service SetElement;

    /** specializes HierarchyElement,
     if this element is a child of a <em>Group</em>.
     <p>This is an alternative to AccessRootElement
     or SetElement.
     </p>
*/
    [optional] service GroupElement;
};


}; }; }; };

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
