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 26package javax.naming; 27 28/** 29 * This class represents a Reference whose contents is a name, called the link name, 30 * that is bound to an atomic name in a context. 31 *<p> 32 * The name is a URL, or a name to be resolved relative to the initial 33 * context, or if the first character of the name is ".", the name 34 * is relative to the context in which the link is bound. 35 *<p> 36 * Normal resolution of names in context operations always follow links. 37 * Resolution of the link name itself may cause resolution to pass through 38 * other links. This gives rise to the possibility of a cycle of links whose 39 * resolution could not terminate normally. As a simple means to avoid such 40 * non-terminating resolutions, service providers may define limits on the 41 * number of links that may be involved in any single operation invoked 42 * by the caller. 43 *<p> 44 * A LinkRef contains a single StringRefAddr, whose type is "LinkAddress", 45 * and whose contents is the link name. The class name field of the 46 * Reference is that of this (LinkRef) class. 47 *<p> 48 * LinkRef is bound to a name using the normal Context.bind()/rebind(), and 49 * DirContext.bind()/rebind(). Context.lookupLink() is used to retrieve the link 50 * itself if the terminal atomic name is bound to a link. 51 *<p> 52 * Many naming systems support a native notion of link that may be used 53 * within the naming system itself. JNDI does not specify whether 54 * there is any relationship between such native links and JNDI links. 55 *<p> 56 * A LinkRef instance is not synchronized against concurrent access by multiple 57 * threads. Threads that need to access a LinkRef instance concurrently should 58 * synchronize amongst themselves and provide the necessary locking. 59 * 60 * @author Rosanna Lee 61 * @author Scott Seligman 62 * 63 * @see LinkException 64 * @see LinkLoopException 65 * @see MalformedLinkException 66 * @see Context#lookupLink 67 * @since 1.3 68 */ 69 70 /*<p> 71 * The serialized form of a LinkRef object consists of the serialized 72 * fields of its Reference superclass. 73 */ 74 75public class LinkRef extends Reference { 76 /* code for link handling */ 77 static final String linkClassName = LinkRef.class.getName(); 78 static final String linkAddrType = "LinkAddress"; 79 80 /** 81 * Constructs a LinkRef for a name. 82 * @param linkName The non-null name for which to create this link. 83 */ 84 public LinkRef(Name linkName) { 85 super(linkClassName, new StringRefAddr(linkAddrType, linkName.toString())); 86 } 87 88 /** 89 * Constructs a LinkRef for a string name. 90 * @param linkName The non-null name for which to create this link. 91 */ 92 public LinkRef(String linkName) { 93 super(linkClassName, new StringRefAddr(linkAddrType, linkName)); 94 } 95 96 /** 97 * Retrieves the name of this link. 98 * 99 * @return The non-null name of this link. 100 * @exception MalformedLinkException If a link name could not be extracted 101 * @exception NamingException If a naming exception was encountered. 102 */ 103 public String getLinkName() throws NamingException { 104 if (className != null && className.equals(linkClassName)) { 105 RefAddr addr = get(linkAddrType); 106 if (addr != null && addr instanceof StringRefAddr) { 107 return (String)((StringRefAddr)addr).getContent(); 108 } 109 } 110 throw new MalformedLinkException(); 111 } 112 /** 113 * Use serialVersionUID from JNDI 1.1.1 for interoperability 114 */ 115 private static final long serialVersionUID = -5386290613498931298L; 116} 117