001 /*
002 * Copyright (c) 2001-2004 Caucho Technology, Inc. All rights reserved.
003 *
004 * The Apache Software License, Version 1.1
005 *
006 * Redistribution and use in source and binary forms, with or without
007 * modification, are permitted provided that the following conditions
008 * are met:
009 *
010 * 1. Redistributions of source code must retain the above copyright
011 * notice, this list of conditions and the following disclaimer.
012 *
013 * 2. Redistributions in binary form must reproduce the above copyright
014 * notice, this list of conditions and the following disclaimer in
015 * the documentation and/or other materials provided with the
016 * distribution.
017 *
018 * 3. The end-user documentation included with the redistribution, if
019 * any, must include the following acknowlegement:
020 * "This product includes software developed by the
021 * Caucho Technology (http://www.caucho.com/)."
022 * Alternately, this acknowlegement may appear in the software itself,
023 * if and wherever such third-party acknowlegements normally appear.
024 *
025 * 4. The names "Burlap", "Hessian", "Resin", and "Caucho" must not be
026 * used to endorse or promote products derived from this software
027 * without prior written permission. For written permission, please contact
028 * info@caucho.com.
029 *
030 * 5. Products derived from this software may not be called "Resin"
031 * nor may "Resin" appear in their names without prior written
032 * permission of Caucho Technology.
033 *
034 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
035 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
036 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
037 * DISCLAIMED. IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
038 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
039 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
040 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
041 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
042 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
043 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
044 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
045 *
046 * @author Scott Ferguson
047 */
048
049 package com.caucho.services.name;
050
051 /**
052 * A read-only name service. The name service provides hierarchical
053 * object lookup. The path names are separated by '/'.
054 *
055 * <p>Because the name service is hierarchical, a lookup of an intermediate
056 * node will return a NameServer instance.
057 *
058 * <p>The following example is a simple use of the NameServer:
059 * <pre>
060 * /dir-1/1 - where foo contains the string "foo-1"
061 * /dir-1/2 - where foo contains the string "foo-2"
062 * /dir-2/1 - where foo contains the string "foo-1"
063 * /dir-2/2 - where foo contains the string "foo-2"
064 * </pre>
065 *
066 * <p/>The root server might have a URL like:
067 * <pre>
068 * http://www.caucho.com/hessian/hessian/name?ejbid=/
069 * </pre>
070 *
071 * <p/>So <code>root.lookup("/dir-1/1")</code> will return the string
072 * "foo-1", and <code>root.lookup("/dir-1")</code> will return the
073 * NameServer with the URL:
074 * <pre>
075 * http://www.caucho.com/hessian/hessian/name?ejbid=/dir-1
076 * </pre>
077 */
078 public interface NameServer {
079 /**
080 * Lookup an object from the name server.
081 *
082 * @param name the relative path name
083 *
084 * @return the matching object or null if no object maches
085 *
086 * @exception NameServiceException if there's an error
087 */
088 public Object lookup(String name)
089 throws NameServiceException;
090
091 /**
092 * Lists all the object name components directly below the current context.
093 * The names are the relative compent name.
094 *
095 * <p>For example, if the name server context is "/dir-1", the returned
096 * values will be ["1", "2"].
097 */
098 public String []list()
099 throws NameServiceException;
100 }