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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package javax.naming.spi;
import java.util.Hashtable;
import javax.naming.*;
import javax.naming.directory.Attributes;
/**
* This interface represents a factory for creating an object given
* an object and attributes about the object.
*<p>
* The JNDI framework allows for object implementations to
* be loaded in dynamically via <em>object factories</em>. See
* <tt>ObjectFactory</tt> for details.
* <p>
* A <tt>DirObjectFactory</tt> extends <tt>ObjectFactory</tt> by allowing
* an <tt>Attributes</tt> instance
* to be supplied to the <tt>getObjectInstance()</tt> method.
* <tt>DirObjectFactory</tt> implementations are intended to be used by <tt>DirContext</tt>
* service providers. The service provider, in addition reading an
* object from the directory, might already have attributes that
* are useful for the object factory to check to see whether the
* factory is supposed to process the object. For instance, an LDAP-style
* service provider might have read the "objectclass" of the object.
* A CORBA object factory might be interested only in LDAP entries
* with "objectclass=corbaObject". By using the attributes supplied by
* the LDAP service provider, the CORBA object factory can quickly
* eliminate objects that it need not worry about, and non-CORBA object
* factories can quickly eliminate CORBA-related LDAP entries.
*
* @author Rosanna Lee
* @author Scott Seligman
*
* @see NamingManager#getObjectInstance
* @see DirectoryManager#getObjectInstance
* @see ObjectFactory
* @since 1.3
*/
public interface DirObjectFactory extends ObjectFactory {
/**
* Creates an object using the location or reference information, and attributes
* specified.
* <p>
* Special requirements of this object are supplied
* using <code>environment</code>.
* An example of such an environment property is user identity
* information.
*<p>
* <tt>DirectoryManager.getObjectInstance()</tt>
* successively loads in object factories. If it encounters a <tt>DirObjectFactory</tt>,
* it will invoke <tt>DirObjectFactory.getObjectInstance()</tt>;
* otherwise, it invokes
* <tt>ObjectFactory.getObjectInstance()</tt>. It does this until a factory
* produces a non-null answer.
* <p> When an exception
* is thrown by an object factory, the exception is passed on to the caller
* of <tt>DirectoryManager.getObjectInstance()</tt>. The search for other factories
* that may produce a non-null answer is halted.
* An object factory should only throw an exception if it is sure that
* it is the only intended factory and that no other object factories
* should be tried.
* If this factory cannot create an object using the arguments supplied,
* it should return null.
*<p>Since <tt>DirObjectFactory</tt> extends <tt>ObjectFactory</tt>, it
* effectively
* has two <tt>getObjectInstance()</tt> methods, where one differs from the other by
* the attributes argument. Given a factory that implements <tt>DirObjectFactory</tt>,
* <tt>DirectoryManager.getObjectInstance()</tt> will only
* use the method that accepts the attributes argument, while
* <tt>NamingManager.getObjectInstance()</tt> will only use the one that does not accept
* the attributes argument.
*<p>
* See <tt>ObjectFactory</tt> for a description URL context factories and other
* properties of object factories that apply equally to <tt>DirObjectFactory</tt>.
*<p>
* The <tt>name</tt>, <tt>attrs</tt>, and <tt>environment</tt> parameters
* are owned by the caller.
* The implementation will not modify these objects or keep references
* to them, although it may keep references to clones or copies.
*
* @param obj The possibly null object containing location or reference
* information that can be used in creating an object.
* @param name The name of this object relative to <code>nameCtx</code>,
* or null if no name is specified.
* @param nameCtx The context relative to which the <code>name</code>
* parameter is specified, or null if <code>name</code> is
* relative to the default initial context.
* @param environment The possibly null environment that is used in
* creating the object.
* @param attrs The possibly null attributes containing some of <tt>obj</tt>'s
* attributes. <tt>attrs</tt> might not necessarily have all of <tt>obj</tt>'s
* attributes. If the object factory requires more attributes, it needs
* to get it, either using <tt>obj</tt>, or <tt>name</tt> and <tt>nameCtx</tt>.
* The factory must not modify attrs.
* @return The object created; null if an object cannot be created.
* @exception Exception If this object factory encountered an exception
* while attempting to create an object, and no other object factories are
* to be tried.
*
* @see DirectoryManager#getObjectInstance
* @see NamingManager#getURLContext
*/
public Object getObjectInstance(Object obj, Name name, Context nameCtx,
Hashtable<?,?> environment,
Attributes attrs)
throws Exception;
}