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1 /* |
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2 * Copyright (c) 1999, 2004, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 package javax.naming.spi; |
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26 |
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27 import javax.naming.*; |
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28 import java.util.Hashtable; |
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29 |
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30 /** |
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31 * This interface represents a factory for obtaining the state of an |
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32 * object for binding. |
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33 *<p> |
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34 * The JNDI framework allows for object implementations to |
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35 * be loaded in dynamically via <em>object factories</em>. |
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36 * For example, when looking up a printer bound in the name space, |
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37 * if the print service binds printer names to {@code Reference}s, the printer |
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38 * {@code Reference} could be used to create a printer object, so that |
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39 * the caller of lookup can directly operate on the printer object |
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40 * after the lookup. |
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41 * <p>An {@code ObjectFactory} is responsible |
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42 * for creating objects of a specific type. In the above example, |
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43 * you may have a {@code PrinterObjectFactory} for creating |
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44 * {@code Printer} objects. |
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45 * <p> |
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46 * For the reverse process, when an object is bound into the namespace, |
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47 * JNDI provides <em>state factories</em>. |
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48 * Continuing with the printer example, suppose the printer object is |
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49 * updated and rebound: |
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50 * <blockquote><pre> |
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51 * ctx.rebind("inky", printer); |
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52 * </pre></blockquote> |
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53 * The service provider for {@code ctx} uses a state factory |
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54 * to obtain the state of {@code printer} for binding into its namespace. |
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55 * A state factory for the {@code Printer} type object might return |
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56 * a more compact object for storage in the naming system. |
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57 *<p> |
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58 * A state factory must implement the {@code StateFactory} interface. |
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59 * In addition, the factory class must be public and must have a |
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60 * public constructor that accepts no parameters. |
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61 * Note that in cases where the factory is in a named module then it must be |
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62 * in a package which is exported by that module to the {@code java.naming} |
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63 * module. |
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64 *<p> |
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65 * The {@code getStateToBind()} method of a state factory may |
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66 * be invoked multiple times, possibly using different parameters. |
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67 * The implementation is thread-safe. |
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68 *<p> |
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69 * {@code StateFactory} is intended for use with service providers |
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70 * that implement only the {@code Context} interface. |
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71 * {@code DirStateFactory} is intended for use with service providers |
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72 * that implement the {@code DirContext} interface. |
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73 * |
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74 * @author Rosanna Lee |
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75 * @author Scott Seligman |
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76 * |
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77 * @see NamingManager#getStateToBind |
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78 * @see DirectoryManager#getStateToBind |
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79 * @see ObjectFactory |
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80 * @see DirStateFactory |
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81 * @since 1.3 |
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82 */ |
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83 public interface StateFactory { |
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84 /** |
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85 * Retrieves the state of an object for binding. |
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86 *<p> |
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87 * {@code NamingManager.getStateToBind()} |
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88 * successively loads in state factories and invokes this method |
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89 * on them until one produces a non-null answer. |
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90 * {@code DirectoryManager.getStateToBind()} |
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91 * successively loads in state factories. If a factory implements |
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92 * {@code DirStateFactory}, then {@code DirectoryManager} |
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93 * invokes {@code DirStateFactory.getStateToBind()}; otherwise |
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94 * it invokes {@code StateFactory.getStateToBind()}. |
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95 *<p> When an exception |
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96 * is thrown by a factory, the exception is passed on to the caller |
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97 * of {@code NamingManager.getStateToBind()} and |
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98 * {@code DirectoryManager.getStateToBind()}. |
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99 * The search for other factories |
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100 * that may produce a non-null answer is halted. |
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101 * A factory should only throw an exception if it is sure that |
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102 * it is the only intended factory and that no other factories |
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103 * should be tried. |
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104 * If this factory cannot create an object using the arguments supplied, |
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105 * it should return null. |
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106 * <p> |
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107 * The <code>name</code> and <code>nameCtx</code> parameters may |
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108 * optionally be used to specify the name of the object being created. |
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109 * See the description of "Name and Context Parameters" in |
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110 * {@link ObjectFactory#getObjectInstance ObjectFactory.getObjectInstance()} |
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111 * for details. |
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112 * If a factory uses <code>nameCtx</code> it should synchronize its use |
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113 * against concurrent access, since context implementations are not |
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114 * guaranteed to be thread-safe. |
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115 * <p> |
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116 * The {@code name} and {@code environment} parameters |
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117 * are owned by the caller. |
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118 * The implementation will not modify these objects or keep references |
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119 * to them, although it may keep references to clones or copies. |
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120 * |
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121 * @param obj A non-null object whose state is to be retrieved. |
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122 * @param name The name of this object relative to <code>nameCtx</code>, |
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123 * or null if no name is specified. |
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124 * @param nameCtx The context relative to which the <code>name</code> |
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125 * parameter is specified, or null if <code>name</code> is |
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126 * relative to the default initial context. |
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127 * @param environment The possibly null environment to |
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128 * be used in the creation of the object's state. |
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129 * @return The object's state for binding; |
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130 * null if the factory is not returning any changes. |
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131 * @exception NamingException if this factory encountered an exception |
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132 * while attempting to get the object's state, and no other factories are |
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133 * to be tried. |
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134 * |
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135 * @see NamingManager#getStateToBind |
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136 * @see DirectoryManager#getStateToBind |
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137 */ |
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138 public Object getStateToBind(Object obj, Name name, Context nameCtx, |
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139 Hashtable<?,?> environment) |
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140 throws NamingException; |
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141 } |