J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2004 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 com.sun.jndi.dns; |
| 27 | |
| 28 | |
| 29 | import java.net.MalformedURLException; |
| 30 | import java.util.ArrayList; |
| 31 | import java.util.Hashtable; |
| 32 | import java.util.List; |
| 33 | |
| 34 | import javax.naming.*; |
| 35 | import javax.naming.spi.*; |
| 36 | |
| 37 | import com.sun.jndi.toolkit.url.UrlUtil; |
| 38 | import sun.net.dns.ResolverConfiguration; // available since 1.4.1 |
| 39 | |
| 40 | |
| 41 | /** |
| 42 | * A DnsContextFactory serves as the initial context factory for DNS. |
| 43 | * |
| 44 | * <p> When an initial context is being created, the environment |
| 45 | * property "java.naming.provider.url" should contain a DNS pseudo-URL |
| 46 | * (see DnsUrl) or a space-separated list of them. Multiple URLs must |
| 47 | * all have the same domain value. |
| 48 | * If the property is not set, the default "dns:" is used. |
| 49 | * |
| 50 | * @author Scott Seligman |
| 51 | */ |
| 52 | |
| 53 | |
| 54 | public class DnsContextFactory implements InitialContextFactory { |
| 55 | |
| 56 | private static final String DEFAULT_URL = "dns:"; |
| 57 | |
| 58 | |
| 59 | public Context getInitialContext(Hashtable<?,?> env) throws NamingException { |
| 60 | if (env == null) { |
| 61 | env = new Hashtable(5); |
| 62 | } |
| 63 | return urlToContext(getInitCtxUrl(env), env); |
| 64 | } |
| 65 | |
| 66 | public static DnsContext getContext(String domain, |
| 67 | String[] servers, Hashtable<?,?> env) |
| 68 | throws NamingException { |
| 69 | return new DnsContext(domain, servers, env); |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * "urls" are used to determine the servers, but any domain |
| 74 | * components are overridden by "domain". |
| 75 | */ |
| 76 | public static DnsContext getContext(String domain, |
| 77 | DnsUrl[] urls, Hashtable env) |
| 78 | throws NamingException { |
| 79 | |
| 80 | String[] servers = serversForUrls(urls); |
| 81 | DnsContext ctx = getContext(domain, servers, env); |
| 82 | if (platformServersUsed(urls)) { |
| 83 | ctx.setProviderUrl(constructProviderUrl(domain, servers)); |
| 84 | } |
| 85 | return ctx; |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * Public for use by product test suite. |
| 90 | */ |
| 91 | public static boolean platformServersAvailable() { |
| 92 | return !ResolverConfiguration.open().nameservers().isEmpty(); |
| 93 | } |
| 94 | |
| 95 | private static Context urlToContext(String url, Hashtable env) |
| 96 | throws NamingException { |
| 97 | |
| 98 | DnsUrl[] urls; |
| 99 | try { |
| 100 | urls = DnsUrl.fromList(url); |
| 101 | } catch (MalformedURLException e) { |
| 102 | throw new ConfigurationException(e.getMessage()); |
| 103 | } |
| 104 | if (urls.length == 0) { |
| 105 | throw new ConfigurationException( |
| 106 | "Invalid DNS pseudo-URL(s): " + url); |
| 107 | } |
| 108 | String domain = urls[0].getDomain(); |
| 109 | |
| 110 | // If multiple urls, all must have the same domain. |
| 111 | for (int i = 1; i < urls.length; i++) { |
| 112 | if (!domain.equalsIgnoreCase(urls[i].getDomain())) { |
| 113 | throw new ConfigurationException( |
| 114 | "Conflicting domains: " + url); |
| 115 | } |
| 116 | } |
| 117 | return getContext(domain, urls, env); |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * Returns all the servers specified in a set of URLs. |
| 122 | * If a URL has no host (or port), the servers configured on the |
| 123 | * underlying platform are used if possible. If no configured |
| 124 | * servers can be found, then fall back to the old behavior of |
| 125 | * using "localhost". |
| 126 | * There must be at least one URL. |
| 127 | */ |
| 128 | private static String[] serversForUrls(DnsUrl[] urls) |
| 129 | throws NamingException { |
| 130 | |
| 131 | if (urls.length == 0) { |
| 132 | throw new ConfigurationException("DNS pseudo-URL required"); |
| 133 | } |
| 134 | |
| 135 | List servers = new ArrayList(); |
| 136 | |
| 137 | for (int i = 0; i < urls.length; i++) { |
| 138 | String server = urls[i].getHost(); |
| 139 | int port = urls[i].getPort(); |
| 140 | |
| 141 | if (server == null && port < 0) { |
| 142 | // No server or port given, so look to underlying platform. |
| 143 | // ResolverConfiguration does some limited caching, so the |
| 144 | // following is reasonably efficient even if called rapid-fire. |
| 145 | List platformServers = |
| 146 | ResolverConfiguration.open().nameservers(); |
| 147 | if (!platformServers.isEmpty()) { |
| 148 | servers.addAll(platformServers); |
| 149 | continue; // on to next URL (if any, which is unlikely) |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | if (server == null) { |
| 154 | server = "localhost"; |
| 155 | } |
| 156 | servers.add((port < 0) |
| 157 | ? server |
| 158 | : server + ":" + port); |
| 159 | } |
| 160 | return (String[]) servers.toArray( |
| 161 | new String[servers.size()]); |
| 162 | } |
| 163 | |
| 164 | /* |
| 165 | * Returns true if serversForUrls(urls) would make use of servers |
| 166 | * from the underlying platform. |
| 167 | */ |
| 168 | private static boolean platformServersUsed(DnsUrl[] urls) { |
| 169 | if (!platformServersAvailable()) { |
| 170 | return false; |
| 171 | } |
| 172 | for (int i = 0; i < urls.length; i++) { |
| 173 | if (urls[i].getHost() == null && |
| 174 | urls[i].getPort() < 0) { |
| 175 | return true; |
| 176 | } |
| 177 | } |
| 178 | return false; |
| 179 | } |
| 180 | |
| 181 | /* |
| 182 | * Returns a value for the PROVIDER_URL property (space-separated URL |
| 183 | * Strings) that reflects the given domain and servers. |
| 184 | * Each server is of the form "server[:port]". |
| 185 | * There must be at least one server. |
| 186 | * IPv6 literal host names include delimiting brackets. |
| 187 | */ |
| 188 | private static String constructProviderUrl(String domain, |
| 189 | String[] servers) { |
| 190 | String path = ""; |
| 191 | if (!domain.equals(".")) { |
| 192 | try { |
| 193 | path = "/" + UrlUtil.encode(domain, "ISO-8859-1"); |
| 194 | } catch (java.io.UnsupportedEncodingException e) { |
| 195 | // assert false : "ISO-Latin-1 charset unavailable"; |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | StringBuffer buf = new StringBuffer(); |
| 200 | for (int i = 0; i < servers.length; i++) { |
| 201 | if (i > 0) { |
| 202 | buf.append(' '); |
| 203 | } |
| 204 | buf.append("dns://").append(servers[i]).append(path); |
| 205 | } |
| 206 | return buf.toString(); |
| 207 | } |
| 208 | |
| 209 | /* |
| 210 | * Reads environment to find URL(s) of initial context. |
| 211 | * Default URL is "dns:". |
| 212 | */ |
| 213 | private static String getInitCtxUrl(Hashtable env) { |
| 214 | String url = (String) env.get(Context.PROVIDER_URL); |
| 215 | return ((url != null) ? url : DEFAULT_URL); |
| 216 | } |
| 217 | } |