xref: /trunk/main/offapi/com/sun/star/configuration/ConfigurationProvider.idl (revision a893be29)

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#ifndef __com_sun_star_configuration_ConfigurationProvider_idl__
#define __com_sun_star_configuration_ConfigurationProvider_idl__

#ifndef __com_sun_star_lang_XMultiServiceFactory_idl__
#include <com/sun/star/lang/XMultiServiceFactory.idl>
#endif

#ifndef __com_sun_star_lang_XComponent_idl__
#include <com/sun/star/lang/XComponent.idl>
#endif

//=============================================================================

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

//=============================================================================
/** manages one, or more, complete sets of configuration data and serves as a
 factory for objects that provide access to a subset of the configuration.

 <p>An implementation is usually obtained from a
 <type scope="com::sun::star::lang">ServiceManager</type>. The arguments passed to
 <member scope="com::sun::star::lang">XMultiComponentFactory::createInstanceWithContextAndArguments()</member>
 select the configuration data source. Arguments must be provided as
 <type scope="com::sun::star::beans">NamedValue</type>
 or <type scope="com::sun::star::beans">PropertyValue</type>.
 If the parameters given are incomplete missing values are taken
 from the context or the environment. If an instance already exists for the
 given set of arguments, the existing instance may be reused.
 In particular, instantiating a provider without explicit arguments to access
 the default configuration data will always yield the same
 <type scope="com::sun::star::configuration">DefaultProvider</type> object.
 </p>
 <p>Some arguments for
 <member scope="com::sun::star::lang">XMultiServiceFactory::createInstanceWithArguments()</member>
 may be given default values during creation of this service. In particular
 this applies to the parameters <code>"Locale"</code> and <code>"EnableAsync"</code>.
 </p>
 */
published service ConfigurationProvider
{
/** allows creating access objects for specific views such as subsets and fragments
 of the configuration.

 <p>The parameter <var>aServiceSpecifier</var> passed to
 <member scope="com::sun::star::lang">XMultiServiceFactory::createInstanceWithArguments()</member>
 supports at least the service specifiers
 <code>"com.sun.star.configuration.ConfigurationAccess"</code> and
 <code>"com.sun.star.configuration.ConfigurationUpdateAccess"</code>.
 </p>

 <p>Using the first of these service specifiers requests a read-only view of
 the configuration.
 The object that is created implements service <type>ConfigurationAccess</type>.
 To reflect its <em>element role</em> as root of the view, it implements
 service <type>AccessRootElement</type>.
 </p>

 <p>Using the second form requests an updatable view of the configuration.
 The object that is created should implement service
 <type>ConfigurationUpdateAccess</type>. To reflect its <em>element role</em>
 which includes controlling updates for the whole view, it implements
 service <type>UpdateRootElement</type>.
 <BR />If the root element of the view is marked read-only (as indicated
 by <const scope="com::sun::star::beans">PropertyAttributes::READONLY</const>),
 the implementation may either raise an exception or return a (read-only)
 <type>ConfigurationAccess</type>/<type>AccessRootElement</type> instead.
 </p>

 <p>The arguments passed to
 <member scope="com::sun::star::lang">XMultiServiceFactory::createInstanceWithArguments()</member>
 in parameter <var>aArguments</var> specify the view of the configuration that
 should be created. That is, they determine the subset of elements that can be
 accessed starting from the returned object. Each element of the argument
 sequence should be a <type scope="com::sun::star::beans">PropertyValue</type>
 or a <type scope="com::sun::star::beans">NamedValue</type>,
 so that the parameters can be identified by name rather than by position.
 </p>

 <p>What combinations of arguments are supported depends on the service name.
 </p>

 <p>With both of the standard service-specifiers above, an implementation must
 accept a single argument named <code>nodepath</code> of type <atom>string</atom>.
 This argument must contain the absolute path to an element of the
 configuration. The view that is selected consists of the named element and
 all its descendants.
 </p>

 <p>Other arguments can be used to control the behavior of the view. These
 are different for different implementations. Whether and how they are used
 may also depend on the configuration store and configuration that were
 selected when the provider was created.
 </p>

 <p>An implementation must ignore unknown arguments.</p>

 <p>Some parameters that are commonly supported are:</p>

 <ul>
    <li>
       <strong>Selecting data into a view:</strong>
       <dl>
	     <dt><code>"nodepath"</code> : <atom>string</atom></dt>
	     <dd>specifies the location of the view root in the configuration.</dd>
	     <dt><code>"depth"</code> : <atom>short</atom></dt>
	     <dd>specifies that elements of the hierarchy that are more than the given
	      number of nesting levels away from the root need not be included in the
	      view.
	     </dd>
	     <dt><code>"locale"</code> : <type scope="com::sun::star::lang">Locale</type></dt>
	     <dd>specifies the locale for which localized values should be
		  retrieved.
		 </dd>
       </dl>

	   <p><strong>Example:</strong> In the hierarchy
<BR /><pre>
 A - B1 - C1
   |
   - B2 - C2 (localized: de, en, fr, ..)
   |    |
   |    - C3 - D1
   |    |    |
   |    |    - D2 - E1
   |    |
   |    - C4 - D3 - E2 - F1
   |    |              |
   |    |              - F2
   |    |
   |    - C5
   |
   - B3
   |
   - B4 - C6 - D4 - E3

</pre>
         <BR />selecting a view with <code>nodepath = "/A/B2"</code>,
		 <code>depth = 2</code> and <code>locale = &lt;Locale for en_US&gt;</code>
		 would result in the tree fragment
<BR /><pre>
(A-) B2 - C2 (en)
        |
        - C3 - D1
        |    |
        |    - D2 (..)
        |
        - C4 - D3 (..)
        |
        - C5

</pre>
	   </p>
    </li>

    <li>
       <strong>Controlling cache behavior:</strong> (with providers that
	    cache configuration data)
       <dl>
	     <dt><code>"enableasync"</code> : <atom>boolean</atom></dt>
	     <dd>controls how updates are handled in the cache. If <TRUE/>, the
		  cache may operate in <em>write-back</em> mode, where updates at
		  first only affect the cache and are written to persistent storage
		  at some later time. If <FALSE/>, the cache must operate in
		  <em>write-through</em> mode, where updates are written to persistent
		  storage at once - that is before
		  <member scope="com::sun::star::util">XChangesBatch::commitChanges()</member>
		  returns.
          <p><em>This parameter was formerly called <code>"lazywrite"</code>.
            The old name should still be supported for compatibility.
          </em></p>
		 </dd>

	     <dt><code>"nocache"</code> : <atom>boolean</atom></dt>
	     <dd>This deprecated parameter
          specifies that data for the view is not taken from the cache, but
		  read directly from storage. This may entail that future changes that
		  become visible in the cache are not reflected in this view and that
		  changes done through this view are not reflected in the cache.
		  <BR /><strong>Use with caution !</strong>
          <p><em>This parameter is not supported by all implementations and may be
          silently ignored !
          </em></p>
		 </dd>
       </dl>
    </li>
 </ul>

 <p><member scope="com::sun::star::lang">XMultiServiceFactory::createInstance()</member>
 may be unusable. Only an implementation that supports service names that can be
 used with no further arguments support this method. It should return the
 same result as if
 <member scope="com::sun::star::lang">XMultiServiceFactory::createInstanceWithArguments()</member>
 had been called using an empty sequence of arguments.
 </p>
*/
	interface com::sun::star::lang::XMultiServiceFactory;


/** allows controlling or observing the lifetime of the configuration.

 <p>The owner of the provider may dispose of this object
 using <member scope="com::sun::star::lang">XComponent::dispose()</member>.
 Note that the default provider is owned by the
 <type scope="com::sun::star::lang">ServiceManager</type> and should not be
 disposed of by user code.
 </p>

 <p>Views created by the provider generally refer to data that is managed by
  the provider. Therefore, disposing of the provider will cause all objects
  belonging to these views to be disposed of as well. This does not apply to
  <em>snapshot</em> views that have their own copy of the data, if available.
 </p>

*/
	interface com::sun::star::lang::XComponent;

};

//=============================================================================

}; }; }; };

#endif