libjava/classpath/java/rmi/Naming.java

   1 /* Naming.java --
   2    Copyright (c) 1996, 1997, 1998, 1999, 2004, 2006
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GNU Classpath.
   6
   7 GNU Classpath is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Classpath is distributed in the hope that it will be useful, but
  13 WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Classpath; see the file COPYING.  If not, write to the
  19 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301 USA.
  21
  22 Linking this library statically or dynamically with other modules is
  23 making a combined work based on this library.  Thus, the terms and
  24 conditions of the GNU General Public License cover the whole
  25 combination.
  26
  27 As a special exception, the copyright holders of this library give you
  28 permission to link this library with independent modules to produce an
  29 executable, regardless of the license terms of these independent
  30 modules, and to copy and distribute the resulting executable under
  31 terms of your choice, provided that you also meet, for each linked
  32 independent module, the terms and conditions of the license of that
  33 module.  An independent module is a module which is not derived from
  34 or based on this library.  If you modify this library, you may extend
  35 this exception to your version of the library, but you are not
  36 obligated to do so.  If you do not wish to do so, delete this
  37 exception statement from your version. */
  38
  39
  40 package java.rmi;
  41
  42 import java.net.MalformedURLException;
  43 import java.net.URI;
  44 import java.net.URISyntaxException;
  45 import java.net.URL;
  46 import java.rmi.registry.LocateRegistry;
  47 import java.rmi.registry.Registry;
  48
  49 /**
  50  * <p>
  51  * The <code>Naming</code> class handles interactions with RMI registries.
  52  * Each method takes a URL in <code>String</code> form, which points to
  53  * the RMI registry.  The scheme of the URL is irrelevant.  The relevant
  54  * part is:
  55  * </p>
  56  * <p>
  57  * <code>//host:port/name</code>
  58  * </p>
  59  * <p>
  60  * which tells the method how to locate and access the registry.  The host
  61  * and port are both optional, and default to `localhost' and the standard
  62  * RMI registry port (1099) respectively.  The name is simply a string
  63  * used to refer to a particular service hosted by the registry.  The
  64  * registry does not attempt to interpret this further.
  65  * </p>
  66  * <p>
  67  * RMI services are registered using one of these names, and the same name
  68  * is later used by the client to lookup the service and access its methods.
  69  * Registries can be shared by multiple services, or a service can create
  70  * its own registry using <code>createRegistry()</code>.
  71  * </p>
  72  *
  73  * @author Original author unknown.
  74  * @author Ingo Proetel (proetel@aicas.com)
  75  * @author Guilhem Lavaux (guilhem@kaffe.org)
  76  * @author Jeroen Frijters (jeroen@frijters.net)
  77  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  78  * @since 1.1
  79  */
  80 public final class Naming
  81 {
  82   /**
  83    * This class isn't intended to be instantiated.
  84    */
  85   private Naming()
  86   {
  87   }
  88
  89   /**
  90    * Looks for the remote object that is associated with the named service.
  91    * Name and location is given in form of a URL without a scheme:
  92    *
  93    * <pre>
  94    * //host:port/service-name
  95    * </pre>
  96    *
  97    * The port is optional.
  98    *
  99    * @param name the service name and location
 100    * @return Remote-object that implements the named service
 101    * @throws NotBoundException if no object implements the service
 102    * @throws MalformedURLException
 103    * @throws RemoteException
 104    */
 105   public static Remote lookup(String name) throws NotBoundException,
 106     MalformedURLException, RemoteException
 107   {
 108     URL u = parseURL(name);
 109     String serviceName = getName(u);
 110     return (getRegistry(u).lookup(serviceName));
 111   }
 112
 113   /**
 114    * Try to bind the given object to the given service name.
 115    *
 116    * @param name
 117    * @param obj
 118    * @throws AlreadyBoundException
 119    * @throws MalformedURLException
 120    * @throws RemoteException
 121    */
 122   public static void bind(String name, Remote obj)
 123     throws AlreadyBoundException, MalformedURLException, RemoteException
 124   {
 125     URL u = parseURL(name);
 126     String serviceName = getName(u);
 127     getRegistry(u).bind(serviceName, obj);
 128   }
 129
 130   /**
 131    * Remove a binding for a given service name.
 132    *
 133    * @param name
 134    * @throws RemoteException
 135    * @throws NotBoundException
 136    * @throws MalformedURLException
 137    */
 138   public static void unbind(String name) throws RemoteException,
 139     NotBoundException, MalformedURLException
 140   {
 141     URL u = parseURL(name);
 142     String serviceName = getName(u);
 143     getRegistry(u).unbind(serviceName);
 144   }
 145
 146   /**
 147    * Forces the binding between the given Remote-object and the given service
 148    * name, even if there was already an object bound to this name.
 149    *
 150    * @param name
 151    * @param obj
 152    * @throws RemoteException
 153    * @throws MalformedURLException
 154    */
 155   public static void rebind(String name, Remote obj) throws RemoteException,
 156     MalformedURLException
 157   {
 158     URL u = parseURL(name);
 159     String serviceName = getName(u);
 160     getRegistry(u).rebind(serviceName, obj);
 161   }
 162
 163   /**
 164    * Lists all services at the named registry.
 165    *
 166    * @param name url that specifies the registry
 167    * @return list of services at the name registry
 168    * @throws RemoteException
 169    * @throws MalformedURLException
 170    */
 171   public static String[] list(String name) throws RemoteException,
 172     MalformedURLException
 173   {
 174     return (getRegistry(parseURL(name)).list());
 175   }
 176
 177   private static Registry getRegistry(URL u) throws RemoteException
 178   {
 179     if (u.getPort() == - 1)
 180       {
 181         return (LocateRegistry.getRegistry(u.getHost()));
 182       }
 183     else
 184       {
 185         return (LocateRegistry.getRegistry(u.getHost(), u.getPort()));
 186       }
 187   }
 188
 189   /**
 190    * Parses the supplied URL and converts it to use the HTTP protocol. From an
 191    * RMI perspective, the scheme is irrelevant and we want to be able to create
 192    * a URL for which a handler is available.
 193    *
 194    * @param name the URL in String form.
 195    * @throws MalformedURLException if the URL is invalid.
 196    */
 197   private static URL parseURL(String name) throws MalformedURLException
 198   {
 199     try
 200       {
 201         URI uri = new URI(name);
 202         String host = uri.getHost();
 203         int port = uri.getPort();
 204         String query = uri.getQuery();
 205         String path = uri.getPath();
 206         return new URL("http", (host == null ? "localhost" : host),
 207             (port == - 1 ? 1099 : port), uri.getPath()
 208                                          + (query == null ? "" : query));
 209       }
 210     catch (URISyntaxException e)
 211       {
 212         throw new MalformedURLException("The URL syntax was invalid: "
 213                                         + e.getMessage());
 214       }
 215   }
 216
 217   /**
 218    * Checks that the URL contains a name, and removes any leading slashes.
 219    *
 220    * @param url the URL to check.
 221    * @throws MalformedURLException if no name is specified.
 222    */
 223   private static String getName(URL url) throws MalformedURLException
 224   {
 225     String filename = url.getFile();
 226     if (filename.length() == 0)
 227       throw new MalformedURLException("No path specified: " + url);
 228     // If the filename begins with a slash we must cut it for
 229     // name resolution.
 230     if (filename.charAt(0) == '/')
 231       return filename.substring(1);
 232     return filename;
 233   }
 234 }