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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 |
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26 package javax.naming; |
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27 |
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28 /** |
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29 * This class represents a Reference whose contents is a name, called the link name, |
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30 * that is bound to an atomic name in a context. |
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31 *<p> |
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32 * The name is a URL, or a name to be resolved relative to the initial |
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33 * context, or if the first character of the name is ".", the name |
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34 * is relative to the context in which the link is bound. |
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35 *<p> |
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36 * Normal resolution of names in context operations always follow links. |
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37 * Resolution of the link name itself may cause resolution to pass through |
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38 * other links. This gives rise to the possibility of a cycle of links whose |
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39 * resolution could not terminate normally. As a simple means to avoid such |
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40 * non-terminating resolutions, service providers may define limits on the |
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41 * number of links that may be involved in any single operation invoked |
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42 * by the caller. |
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43 *<p> |
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44 * A LinkRef contains a single StringRefAddr, whose type is "LinkAddress", |
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45 * and whose contents is the link name. The class name field of the |
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46 * Reference is that of this (LinkRef) class. |
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47 *<p> |
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48 * LinkRef is bound to a name using the normal Context.bind()/rebind(), and |
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49 * DirContext.bind()/rebind(). Context.lookupLink() is used to retrieve the link |
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50 * itself if the terminal atomic name is bound to a link. |
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51 *<p> |
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52 * Many naming systems support a native notion of link that may be used |
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53 * within the naming system itself. JNDI does not specify whether |
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54 * there is any relationship between such native links and JNDI links. |
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55 *<p> |
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56 * A LinkRef instance is not synchronized against concurrent access by multiple |
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57 * threads. Threads that need to access a LinkRef instance concurrently should |
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58 * synchronize amongst themselves and provide the necessary locking. |
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59 * |
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60 * @author Rosanna Lee |
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61 * @author Scott Seligman |
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62 * |
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63 * @see LinkException |
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64 * @see LinkLoopException |
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65 * @see MalformedLinkException |
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66 * @see Context#lookupLink |
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67 * @since 1.3 |
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68 */ |
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69 |
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70 /*<p> |
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71 * The serialized form of a LinkRef object consists of the serialized |
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72 * fields of its Reference superclass. |
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73 */ |
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74 |
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75 public class LinkRef extends Reference { |
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76 /* code for link handling */ |
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77 static final String linkClassName = LinkRef.class.getName(); |
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78 static final String linkAddrType = "LinkAddress"; |
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79 |
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80 /** |
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81 * Constructs a LinkRef for a name. |
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82 * @param linkName The non-null name for which to create this link. |
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83 */ |
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84 public LinkRef(Name linkName) { |
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85 super(linkClassName, new StringRefAddr(linkAddrType, linkName.toString())); |
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86 } |
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87 |
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88 /** |
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89 * Constructs a LinkRef for a string name. |
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90 * @param linkName The non-null name for which to create this link. |
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91 */ |
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92 public LinkRef(String linkName) { |
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93 super(linkClassName, new StringRefAddr(linkAddrType, linkName)); |
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94 } |
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95 |
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96 /** |
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97 * Retrieves the name of this link. |
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98 * |
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99 * @return The non-null name of this link. |
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100 * @exception MalformedLinkException If a link name could not be extracted |
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101 * @exception NamingException If a naming exception was encountered. |
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102 */ |
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103 public String getLinkName() throws NamingException { |
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104 if (className != null && className.equals(linkClassName)) { |
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105 RefAddr addr = get(linkAddrType); |
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106 if (addr != null && addr instanceof StringRefAddr) { |
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107 return (String)((StringRefAddr)addr).getContent(); |
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108 } |
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109 } |
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110 throw new MalformedLinkException(); |
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111 } |
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112 /** |
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113 * Use serialVersionUID from JNDI 1.1.1 for interoperability |
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114 */ |
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115 private static final long serialVersionUID = -5386290613498931298L; |
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116 } |