J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2004 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package 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 | |
| 75 | public 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 | } |