/*

 * Copyright 1999-2004 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

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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;

}