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 }
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