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| 1 | /* | ||
| 2 | * Copyright (c) 1999, 2010, 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 | |||
| 26 | package javax.naming.ldap; | ||
| 27 | |||
| 28 | import javax.naming.NamingException; | ||
| 29 | import javax.naming.Context; | ||
| 30 | |||
| 31 | import java.util.Hashtable; | ||
| 32 | |||
| 33 | import com.sun.naming.internal.FactoryEnumeration; | ||
| 34 | import com.sun.naming.internal.ResourceManager; | ||
| 35 | |||
| 36 | |||
| 37 | /** | ||
| 38 | * This abstract class represents a factory for creating LDAPv3 controls. | ||
| 39 | * LDAPv3 controls are defined in | ||
| 40 | * <A HREF="http://www.ietf.org/rfc/rfc2251.txt">RFC 2251</A>. | ||
| 41 | *<p> | ||
| 42 | * When a service provider receives a response control, it uses control | ||
| 43 | * factories to return the specific/appropriate control class implementation. | ||
| 44 | * | ||
| 45 | * @author Rosanna Lee | ||
| 46 | * @author Scott Seligman | ||
| 47 | * @author Vincent Ryan | ||
| 48 | * | ||
| 49 | * @see Control | ||
| 50 | * @since 1.3 | ||
| 51 | */ | ||
| 52 | |||
| 53 | public abstract class ControlFactory { | ||
| 54 | /* | ||
| 55 | * Creates a new instance of a control factory. | ||
| 56 | */ | ||
| 57 | protected ControlFactory() { | ||
| 58 | } | ||
| 59 | |||
| 60 | /** | ||
| 61 | * Creates a control using this control factory. | ||
| 62 | *<p> | ||
| 63 | * The factory is used by the service provider to return controls | ||
| 64 | * that it reads from the LDAP protocol as specialized control classes. | ||
| 65 | * Without this mechanism, the provider would be returning | ||
| 66 | * controls that only contained data in BER encoded format. | ||
| 67 | *<p> | ||
| 68 | * Typically, <tt>ctl</tt> is a "basic" control containing | ||
| 69 | * BER encoded data. The factory is used to create a specialized | ||
| 70 | * control implementation, usually by decoding the BER encoded data, | ||
| 71 | * that provides methods to access that data in a type-safe and friendly | ||
| 72 | * manner. | ||
| 73 | * <p> | ||
| 74 | * For example, a factory might use the BER encoded data in | ||
| 75 | * basic control and return an instance of a VirtualListReplyControl. | ||
| 76 | *<p> | ||
| 77 | * If this factory cannot create a control using the argument supplied, | ||
| 78 | * it should return null. | ||
| 79 | * A factory should only throw an exception if it is sure that | ||
| 80 | * it is the only intended factory and that no other control factories | ||
| 81 | * should be tried. This might happen, for example, if the BER data | ||
| 82 | * in the control does not match what is expected of a control with | ||
| 83 | * the given OID. Since this method throws <tt>NamingException</tt>, | ||
| 84 | * any other internally generated exception that should be propagated | ||
| 85 | * must be wrapped inside a <tt>NamingException</tt>. | ||
| 86 | * | ||
| 87 | * @param ctl A non-null control. | ||
| 88 | * | ||
| 89 | * @return A possibly null Control. | ||
| 90 | * @exception NamingException If <tt>ctl</tt> contains invalid data that prevents it | ||
| 91 | * from being used to create a control. A factory should only throw | ||
| 92 | * an exception if it knows how to produce the control (identified by the OID) | ||
| 93 | * but is unable to because of, for example invalid BER data. | ||
| 94 | */ | ||
| 95 | public abstract Control getControlInstance(Control ctl) throws NamingException; | ||
| 96 | |||
| 97 | /** | ||
| 98 | * Creates a control using known control factories. | ||
| 99 | * <p> | ||
| 100 | * The following rule is used to create the control: | ||
| 101 | *<ul> | ||
| 102 | * <li> Use the control factories specified in | ||
| 103 | * the <tt>LdapContext.CONTROL_FACTORIES</tt> property of the | ||
| 104 | * environment, and of the provider resource file associated with | ||
| 105 | * <tt>ctx</tt>, in that order. | ||
| 106 | * The value of this property is a colon-separated list of factory | ||
| 107 | * class names that are tried in order, and the first one that succeeds | ||
| 108 | * in creating the control is the one used. | ||
| 109 | * If none of the factories can be loaded, | ||
| 110 | * return <code>ctl</code>. | ||
| 111 | * If an exception is encountered while creating the control, the | ||
| 112 | * exception is passed up to the caller. | ||
| 113 | *</ul> | ||
| 114 | * <p> | ||
| 115 | * Note that a control factory | ||
| 116 | * must be public and must have a public constructor that accepts no arguments. | ||
| 117 | * <p> | ||
| 118 | * @param ctl The non-null control object containing the OID and BER data. | ||
| 119 | * @param ctx The possibly null context in which the control is being created. | ||
| 120 | * If null, no such information is available. | ||
| 121 | * @param env The possibly null environment of the context. This is used | ||
| 122 | * to find the value of the <tt>LdapContext.CONTROL_FACTORIES</tt> property. | ||
| 123 | * @return A control object created using <code>ctl</code>; or | ||
| 124 | * <code>ctl</code> if a control object cannot be created using | ||
| 125 | * the algorithm described above. | ||
| 126 | * @exception NamingException if a naming exception was encountered | ||
| 127 | * while attempting to create the control object. | ||
| 128 | * If one of the factories accessed throws an | ||
| 129 | * exception, it is propagated up to the caller. | ||
| 130 | * If an error was encountered while loading | ||
| 131 | * and instantiating the factory and object classes, the exception | ||
| 132 | * is wrapped inside a <tt>NamingException</tt> and then rethrown. | ||
| 133 | */ | ||
| 134 | public static Control getControlInstance(Control ctl, Context ctx, | ||
| 135 | Hashtable<?,?> env) | ||
| 136 | throws NamingException { | ||
| 137 | |||
| 138 | // Get object factories list from environment properties or | ||
| 139 | // provider resource file. | ||
| 140 | FactoryEnumeration factories = ResourceManager.getFactories( | ||
| 141 | LdapContext.CONTROL_FACTORIES, env, ctx); | ||
| 142 | |||
| 143 | if (factories == null) { | ||
| 144 | return ctl; | ||
| 145 | } | ||
| 146 | |||
| 147 | // Try each factory until one succeeds | ||
| 148 | Control answer = null; | ||
| 149 | ControlFactory factory; | ||
| 150 | while (answer == null && factories.hasMore()) { | ||
| 151 | factory = (ControlFactory)factories.next(); | ||
| 152 | answer = factory.getControlInstance(ctl); | ||
| 153 | } | ||
| 154 | |||
| 155 | return (answer != null)? answer : ctl; | ||
| 156 | } | ||
| 157 | } | ||