001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.directory.api.ldap.model.message; 021 022 023import java.util.Collection; 024 025 026/** 027 * Represents a referral which is a set of alternative locations where an entry 028 * can be found. Here's what <a href="http://www.faqs.org/rfcs/rfc2251.html"> 029 * RFC 2251 </a> has to say about it: 030 * 031 * <pre> 032 * 4.1.11. Referral 033 * 034 * The referral error indicates that the contacted server does not hold 035 * the target entry of the request. The referral field is present in an 036 * LDAPResult if the LDAPResult.resultCode field value is referral, and 037 * absent with all other result codes. It contains a reference to 038 * another server (or set of servers) which may be accessed via LDAP or 039 * other protocols. Referrals can be returned in response to any 040 * operation request (except unbind and abandon which do not have 041 * responses). At least one URL MUST be present in the Referral. 042 * 043 * The referral is not returned for a singleLevel or wholeSubtree search 044 * in which the search scope spans multiple naming contexts, and several 045 * different servers would need to be contacted to complete the 046 * operation. Instead, continuation references, described in section 047 * 4.5.3, are returned. 048 * 049 * Referral ::= SEQUENCE OF LDAPURL -- one or more 050 * 051 * LDAPURL ::= LDAPString -- limited to characters permitted in URLs 052 * 053 * If the client wishes to progress the operation, it MUST follow the 054 * referral by contacting any one of servers. All the URLs MUST be 055 * equally capable of being used to progress the operation. (The 056 * mechanisms for how this is achieved by multiple servers are outside 057 * the scope of this document.) 058 * 059 * URLs for servers implementing the LDAP protocol are written according 060 * to <a href="http://www.faqs.org/rfcs/rfc2255.html">[9]</a>. If an alias 061 * was dereferenced, the <dn> part of the URL MUST be present, with the new 062 * target object name. If the <dn> part is present, the client MUST use this 063 * name in its next request to progress the operation, and if it is not present 064 * the client will use the same name as in the original request. Some servers 065 * (e.g. participating in distributed indexing) may provide a different filter 066 * in a referral for a search operation. If the filter part of the URL 067 * is present in an LDAPURL, the client MUST use this filter in its next 068 * request to progress this search, and if it is not present the client 069 * MUST use the same filter as it used for that search. Other aspects 070 * of the new request may be the same or different as the request which 071 * generated the referral. 072 * 073 * Note that UTF-8 characters appearing in a Dn or search filter may not 074 * be legal for URLs (e.g. spaces) and MUST be escaped using the % 075 * method in RFC 1738 <a href="http://www.faqs.org/rfcs/rfc1738.html">[7]</a>. 076 * 077 * Other kinds of URLs may be returned, so long as the operation could 078 * be performed using that protocol. 079 * </pre> 080 * 081 * @author <a href="mailto:dev@directory.apache.org"> Apache Directory Project</a> 082 * TODO This interface should be located in a url package under common to be 083 * constructed from a LDAPv3 URL parser. The interface will eventually 084 * look very different once url support is added: for one it will add and 085 * remove LdapUrl objects instead of strings or provide both string and 086 * LdapUrl add/remove methods. 087 */ 088public interface Referral 089{ 090 /** 091 * Gets an unmodifiable set of alternative referral urls. 092 * 093 * @return the alternative url objects. 094 */ 095 Collection<String> getLdapUrls(); 096 097 098 /** 099 * Gets an unmodifiable set of encoded referral urls. 100 * 101 * @return the encoded url objects. 102 */ 103 Collection<byte[]> getLdapUrlsBytes(); 104 105 106 /** 107 * Adds an LDAPv3 URL to this Referral. 108 * 109 * @param url 110 * the LDAPv3 URL to add 111 */ 112 void addLdapUrl( String url ); 113 114 115 /** 116 * Adds an encoded LDAPv3 URL to this Referral. 117 * 118 * @param urlBytes the encoded LDAPv3 URL to add 119 */ 120 void addLdapUrlBytes( byte[] urlBytes ); 121 122 123 /** 124 * Removes an LDAPv3 URL to this Referral. 125 * 126 * @param url 127 * the LDAPv3 URL to remove 128 */ 129 void removeLdapUrl( String url ); 130 131 132 /** 133 * @return The total length of the Referral 134 */ 135 int getReferralLength(); 136 137 138 /** 139 * Set the length of the referral 140 * @param referralLength The total length of the Referral 141 */ 142 void setReferralLength( int referralLength ); 143}