jdk/src/share/classes/javax/naming/spi/DirObjectFactory.java
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     1 /*
       
     2  * Copyright 1999-2004 Sun Microsystems, Inc.  All Rights Reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
     7  * published by the Free Software Foundation.  Sun designates this
       
     8  * particular file as subject to the "Classpath" exception as provided
       
     9  * by Sun in the LICENSE file that accompanied this code.
       
    10  *
       
    11  * This code is distributed in the hope that it will be useful, but WITHOUT
       
    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
       
    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
       
    14  * version 2 for more details (a copy is included in the LICENSE file that
       
    15  * accompanied this code).
       
    16  *
       
    17  * You should have received a copy of the GNU General Public License version
       
    18  * 2 along with this work; if not, write to the Free Software Foundation,
       
    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
    20  *
       
    21  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
       
    22  * CA 95054 USA or visit www.sun.com if you need additional information or
       
    23  * have any questions.
       
    24  */
       
    25 
       
    26 package javax.naming.spi;
       
    27 
       
    28 import java.util.Hashtable;
       
    29 import javax.naming.*;
       
    30 import javax.naming.directory.Attributes;
       
    31 
       
    32 /**
       
    33   * This interface represents a factory for creating an object given
       
    34   * an object and attributes about the object.
       
    35   *<p>
       
    36   * The JNDI framework allows for object implementations to
       
    37   * be loaded in dynamically via <em>object factories</em>. See
       
    38   * <tt>ObjectFactory</tt> for details.
       
    39   * <p>
       
    40   * A <tt>DirObjectFactory</tt> extends <tt>ObjectFactory</tt> by allowing
       
    41   * an <tt>Attributes</tt> instance
       
    42   * to be supplied to the <tt>getObjectInstance()</tt> method.
       
    43   * <tt>DirObjectFactory</tt> implementations are intended to be used by <tt>DirContext</tt>
       
    44   * service providers. The service provider, in addition reading an
       
    45   * object from the directory, might already have attributes that
       
    46   * are useful for the object factory to check to see whether the
       
    47   * factory is supposed to process the object. For instance, an LDAP-style
       
    48   * service provider might have read the "objectclass" of the object.
       
    49   * A CORBA object factory might be interested only in LDAP entries
       
    50   * with "objectclass=corbaObject". By using the attributes supplied by
       
    51   * the LDAP service provider, the CORBA object factory can quickly
       
    52   * eliminate objects that it need not worry about, and non-CORBA object
       
    53   * factories can quickly eliminate CORBA-related LDAP entries.
       
    54   *
       
    55   * @author Rosanna Lee
       
    56   * @author Scott Seligman
       
    57   *
       
    58   * @see NamingManager#getObjectInstance
       
    59   * @see DirectoryManager#getObjectInstance
       
    60   * @see ObjectFactory
       
    61   * @since 1.3
       
    62   */
       
    63 
       
    64 public interface DirObjectFactory extends ObjectFactory {
       
    65 /**
       
    66  * Creates an object using the location or reference information, and attributes
       
    67  * specified.
       
    68  * <p>
       
    69  * Special requirements of this object are supplied
       
    70  * using <code>environment</code>.
       
    71  * An example of such an environment property is user identity
       
    72  * information.
       
    73  *<p>
       
    74  * <tt>DirectoryManager.getObjectInstance()</tt>
       
    75  * successively loads in object factories. If it encounters a <tt>DirObjectFactory</tt>,
       
    76  * it will invoke <tt>DirObjectFactory.getObjectInstance()</tt>;
       
    77  * otherwise, it invokes
       
    78  * <tt>ObjectFactory.getObjectInstance()</tt>. It does this until a factory
       
    79  * produces a non-null answer.
       
    80  * <p> When an exception
       
    81  * is thrown by an object factory, the exception is passed on to the caller
       
    82  * of <tt>DirectoryManager.getObjectInstance()</tt>. The search for other factories
       
    83  * that may produce a non-null answer is halted.
       
    84  * An object factory should only throw an exception if it is sure that
       
    85  * it is the only intended factory and that no other object factories
       
    86  * should be tried.
       
    87  * If this factory cannot create an object using the arguments supplied,
       
    88  * it should return null.
       
    89   *<p>Since <tt>DirObjectFactory</tt> extends <tt>ObjectFactory</tt>, it
       
    90   * effectively
       
    91   * has two <tt>getObjectInstance()</tt> methods, where one differs from the other by
       
    92   * the attributes argument. Given a factory that implements <tt>DirObjectFactory</tt>,
       
    93   * <tt>DirectoryManager.getObjectInstance()</tt> will only
       
    94   * use the method that accepts the attributes argument, while
       
    95   * <tt>NamingManager.getObjectInstance()</tt> will only use the one that does not accept
       
    96   * the attributes argument.
       
    97  *<p>
       
    98  * See <tt>ObjectFactory</tt> for a description URL context factories and other
       
    99  * properties of object factories that apply equally to <tt>DirObjectFactory</tt>.
       
   100  *<p>
       
   101  * The <tt>name</tt>, <tt>attrs</tt>, and <tt>environment</tt> parameters
       
   102  * are owned by the caller.
       
   103  * The implementation will not modify these objects or keep references
       
   104  * to them, although it may keep references to clones or copies.
       
   105  *
       
   106  * @param obj The possibly null object containing location or reference
       
   107  *              information that can be used in creating an object.
       
   108  * @param name The name of this object relative to <code>nameCtx</code>,
       
   109  *              or null if no name is specified.
       
   110  * @param nameCtx The context relative to which the <code>name</code>
       
   111  *              parameter is specified, or null if <code>name</code> is
       
   112  *              relative to the default initial context.
       
   113  * @param environment The possibly null environment that is used in
       
   114  *              creating the object.
       
   115  * @param attrs The possibly null attributes containing some of <tt>obj</tt>'s
       
   116  * attributes. <tt>attrs</tt> might not necessarily have all of <tt>obj</tt>'s
       
   117  * attributes. If the object factory requires more attributes, it needs
       
   118  * to get it, either using <tt>obj</tt>, or <tt>name</tt> and <tt>nameCtx</tt>.
       
   119  *      The factory must not modify attrs.
       
   120  * @return The object created; null if an object cannot be created.
       
   121  * @exception Exception If this object factory encountered an exception
       
   122  * while attempting to create an object, and no other object factories are
       
   123  * to be tried.
       
   124  *
       
   125  * @see DirectoryManager#getObjectInstance
       
   126  * @see NamingManager#getURLContext
       
   127  */
       
   128     public Object getObjectInstance(Object obj, Name name, Context nameCtx,
       
   129                                     Hashtable<?,?> environment,
       
   130                                     Attributes attrs)
       
   131         throws Exception;
       
   132 }