[Hibernate-commits] Hibernate2/doc/reference/src manipulating_data.xml,1.9,1.10

[<one...@us...>]

Update of /cvsroot/hibernate/Hibernate2/doc/reference/src
In directory sc8-pr-cvs1:/tmp/cvs-serv729/doc/reference/src

Modified Files:
	manipulating_data.xml 
Log Message:
doco for metadata API

Index: manipulating_data.xml
===================================================================
RCS file: /cvsroot/hibernate/Hibernate2/doc/reference/src/manipulating_data.xml,v
retrieving revision 1.9
retrieving revision 1.10
diff -C2 -d -r1.9 -r1.10
*** manipulating_data.xml	26 Apr 2003 03:58:29 -0000	1.9
--- manipulating_data.xml	1 May 2003 07:53:20 -0000	1.10
***************
*** 1119,1124 ****
      
      </sect1>
! 
      <sect1 id="manipulating-data-s16">
          <title>Frequently Asked Questions</title>
  
--- 1119,1157 ----
      
      </sect1>
!     
      <sect1 id="manipulating-data-s16">
+         <title>Metadata API</title>
+         <para>
+             Hibernate requires a very rich meta-level model of all entity and value types. From time
+             to time, this model is very useful to the application itself. For example, the application
+             might use Hibernate's metadata to implement a "smart" deep-copy algorithm that understands
+             which objects should be copied (eg. mutable value types) and which should not (eg. 
+             immutable value types and, possibly, associated entities).
+         </para>
+         <para>
+             Hibernate exposes metadata via the <literal>ClassMetadata</literal> and
+             <literal>CollectionMetadata</literal> interfaces and the <literal>Type</literal>
+             hierarchy. Instances of the metadata interfaces may be obtained from the 
+             <literal>SessionFactory</literal>.
+         </para>
+ 
+         <programlisting><![CDATA[Cat fritz = ......;
+ Long id = (Long) catMeta.getIdentifier(fritz);
+ ClassMetadata catMeta = sessionfactory.getClassMetadata(Cat.class);
+ Object[] propertyValues = catMeta.getPropertyValues(fritz);
+ String[] propertyNames = catMeta.getPropertyNames();
+ Type[] propertyTypes = catMeta.getPropertyTypes();
+ // get a Map of all properties which are not collections or associations
+ // TODO: what about components?
+ Map namedValues = new HashMap();
+ for ( int i=0; i<propertyNames.length; i++ ) {
+     if ( !propertyTypes[i].isEntityType() && !propertyTypes[i].isCollectionType() ) {
+         namedValues.put( propertyNames[i], propertyValues[i] );
+     }
+ }]]></programlisting>
+         
+     </sect1>
+     
+     <sect1 id="manipulating-data-s17">
          <title>Frequently Asked Questions</title>