1 /* 2 * Copyright (c) 1999, 2004, Oracle and/or its affiliates. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package javax.naming.spi; 26 27 import javax.naming.*; 28 import java.util.Hashtable; 29 30 /** 31 * This interface represents a factory for obtaining the state of an 32 * object for binding. 33 *<p> 34 * The JNDI framework allows for object implementations to 35 * be loaded in dynamically via <em>object factories</em>. 36 * For example, when looking up a printer bound in the name space, 37 * if the print service binds printer names to {@code Reference}s, the printer 38 * {@code Reference} could be used to create a printer object, so that 39 * the caller of lookup can directly operate on the printer object 40 * after the lookup. 41 * <p>An {@code ObjectFactory} is responsible 42 * for creating objects of a specific type. In the above example, 43 * you may have a {@code PrinterObjectFactory} for creating 44 * {@code Printer} objects. 45 * <p> 46 * For the reverse process, when an object is bound into the namespace, 47 * JNDI provides <em>state factories</em>. 48 * Continuing with the printer example, suppose the printer object is 49 * updated and rebound: 50 * <blockquote><pre> 51 * ctx.rebind("inky", printer); 52 * </pre></blockquote> 53 * The service provider for {@code ctx} uses a state factory 54 * to obtain the state of {@code printer} for binding into its namespace. 55 * A state factory for the {@code Printer} type object might return 56 * a more compact object for storage in the naming system. 57 *<p> 58 * A state factory must implement the {@code StateFactory} interface. 59 * In addition, the factory class must be public and must have a 60 * public constructor that accepts no parameters. 61 *<p> 62 * The {@code getStateToBind()} method of a state factory may 63 * be invoked multiple times, possibly using different parameters. 64 * The implementation is thread-safe. 65 *<p> 66 * {@code StateFactory} is intended for use with service providers 67 * that implement only the {@code Context} interface. 68 * {@code DirStateFactory} is intended for use with service providers 69 * that implement the {@code DirContext} interface. 70 * 71 * @author Rosanna Lee 72 * @author Scott Seligman 73 * 74 * @see NamingManager#getStateToBind 75 * @see DirectoryManager#getStateToBind 76 * @see ObjectFactory 77 * @see DirStateFactory 78 * @since 1.3 79 */ 80 public interface StateFactory { 81 /** 82 * Retrieves the state of an object for binding. 83 *<p> 84 * {@code NamingManager.getStateToBind()} 85 * successively loads in state factories and invokes this method 86 * on them until one produces a non-null answer. 87 * {@code DirectoryManager.getStateToBind()} 88 * successively loads in state factories. If a factory implements 89 * {@code DirStateFactory}, then {@code DirectoryManager} 90 * invokes {@code DirStateFactory.getStateToBind()}; otherwise 91 * it invokes {@code StateFactory.getStateToBind()}. 92 *<p> When an exception 93 * is thrown by a factory, the exception is passed on to the caller 94 * of {@code NamingManager.getStateToBind()} and 95 * {@code DirectoryManager.getStateToBind()}. 96 * The search for other factories 97 * that may produce a non-null answer is halted. 98 * A factory should only throw an exception if it is sure that 99 * it is the only intended factory and that no other factories 100 * should be tried. 101 * If this factory cannot create an object using the arguments supplied, 102 * it should return null. 103 * <p> 104 * The <code>name</code> and <code>nameCtx</code> parameters may 105 * optionally be used to specify the name of the object being created. 106 * See the description of "Name and Context Parameters" in 107 * {@link ObjectFactory#getObjectInstance ObjectFactory.getObjectInstance()} 108 * for details. 109 * If a factory uses <code>nameCtx</code> it should synchronize its use 110 * against concurrent access, since context implementations are not 111 * guaranteed to be thread-safe. 112 * <p> 113 * The {@code name} and {@code environment} parameters 114 * are owned by the caller. 115 * The implementation will not modify these objects or keep references 116 * to them, although it may keep references to clones or copies. 117 * 118 * @param obj A non-null object whose state is to be retrieved. 119 * @param name The name of this object relative to <code>nameCtx</code>, 120 * or null if no name is specified. 121 * @param nameCtx The context relative to which the <code>name</code> 122 * parameter is specified, or null if <code>name</code> is 123 * relative to the default initial context. 124 * @param environment The possibly null environment to 125 * be used in the creation of the object's state. 126 * @return The object's state for binding; 127 * null if the factory is not returning any changes. 128 * @exception NamingException if this factory encountered an exception 129 * while attempting to get the object's state, and no other factories are 130 * to be tried. 131 * 132 * @see NamingManager#getStateToBind 133 * @see DirectoryManager#getStateToBind 134 */ 135 public Object getStateToBind(Object obj, Name name, Context nameCtx, 136 Hashtable<?,?> environment) 137 throws NamingException; 138 }