gcc/libjava/classpath/java/rmi/Naming.java

/* Naming.java --
   Copyright (c) 1996, 1997, 1998, 1999, 2004, 2006  
   Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
 
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
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terms of your choice, provided that you also meet, for each linked
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this exception to your version of the library, but you are not
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exception statement from your version. */


package java.rmi;

import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

/**
 * <p>
 * The <code>Naming</code> class handles interactions with RMI registries.
 * Each method takes a URL in <code>String</code> form, which points to
 * the RMI registry.  The scheme of the URL is irrelevant.  The relevant
 * part is:
 * </p>
 * <p>
 * <code>//host:port/name</code>
 * </p>
 * <p>
 * which tells the method how to locate and access the registry.  The host
 * and port are both optional, and default to `localhost' and the standard
 * RMI registry port (1099) respectively.  The name is simply a string
 * used to refer to a particular service hosted by the registry.  The
 * registry does not attempt to interpret this further.
 * </p>
 * <p>
 * RMI services are registered using one of these names, and the same name
 * is later used by the client to lookup the service and access its methods. 
 * Registries can be shared by multiple services, or a service can create
 * its own registry using <code>createRegistry()</code>.
 * </p>
 *
 * @author Original author unknown.
 * @author Ingo Proetel (proetel@aicas.com)
 * @author Guilhem Lavaux (guilhem@kaffe.org)
 * @author Jeroen Frijters (jeroen@frijters.net)
 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
 * @since 1.1
 */
public final class Naming
{
  /**
   * This class isn't intended to be instantiated.
   */
  private Naming()
  {
  }

  /**
   * Looks for the remote object that is associated with the named service. 
   * Name and location is given in form of a URL without a scheme:
   * 
   * <pre>
   * //host:port/service-name
   * </pre>
   * 
   * The port is optional.
   * 
   * @param name the service name and location
   * @return Remote-object that implements the named service
   * @throws NotBoundException if no object implements the service
   * @throws MalformedURLException
   * @throws RemoteException
   */
  public static Remote lookup(String name) throws NotBoundException,
    MalformedURLException, RemoteException
  {
    URL u = parseURL(name);
    String serviceName = getName(u);
    return (getRegistry(u).lookup(serviceName));
  }

  /**
   * Try to bind the given object to the given service name.
   * 
   * @param name
   * @param obj
   * @throws AlreadyBoundException
   * @throws MalformedURLException
   * @throws RemoteException
   */
  public static void bind(String name, Remote obj)
    throws AlreadyBoundException, MalformedURLException, RemoteException
  {
    URL u = parseURL(name);
    String serviceName = getName(u);
    getRegistry(u).bind(serviceName, obj);
  }

  /**
   * Remove a binding for a given service name.
   * 
   * @param name
   * @throws RemoteException
   * @throws NotBoundException
   * @throws MalformedURLException
   */
  public static void unbind(String name) throws RemoteException,
    NotBoundException, MalformedURLException
  {
    URL u = parseURL(name);
    String serviceName = getName(u);
    getRegistry(u).unbind(serviceName);
  }

  /**
   * Forces the binding between the given Remote-object and the given service
   * name, even if there was already an object bound to this name.
   * 
   * @param name
   * @param obj
   * @throws RemoteException
   * @throws MalformedURLException
   */
  public static void rebind(String name, Remote obj) throws RemoteException,
    MalformedURLException
  {
    URL u = parseURL(name);
    String serviceName = getName(u);
    getRegistry(u).rebind(serviceName, obj);
  }

  /**
   * Lists all services at the named registry.
   * 
   * @param name url that specifies the registry
   * @return list of services at the name registry
   * @throws RemoteException
   * @throws MalformedURLException
   */
  public static String[] list(String name) throws RemoteException,
    MalformedURLException
  {
    return (getRegistry(parseURL(name)).list());
  }

  private static Registry getRegistry(URL u) throws RemoteException
  {
    if (u.getPort() == - 1)
      {
        return (LocateRegistry.getRegistry(u.getHost()));
      }
    else
      {
        return (LocateRegistry.getRegistry(u.getHost(), u.getPort()));
      }
  }

  /**
   * Parses the supplied URL and converts it to use the HTTP protocol. From an
   * RMI perspective, the scheme is irrelevant and we want to be able to create
   * a URL for which a handler is available.
   * 
   * @param name the URL in String form.
   * @throws MalformedURLException if the URL is invalid.
   */
  private static URL parseURL(String name) throws MalformedURLException
  {
    try
      {
        URI uri = new URI(name);
        String host = uri.getHost();
        int port = uri.getPort();
        String query = uri.getQuery();
        String path = uri.getPath();
        return new URL("http", (host == null ? "localhost" : host),
            (port == - 1 ? 1099 : port), uri.getPath()
                                         + (query == null ? "" : query));
      }
    catch (URISyntaxException e)
      {
        throw new MalformedURLException("The URL syntax was invalid: "
                                        + e.getMessage());
      }
  }

  /**
   * Checks that the URL contains a name, and removes any leading slashes.
   * 
   * @param url the URL to check.
   * @throws MalformedURLException if no name is specified.
   */
  private static String getName(URL url) throws MalformedURLException
  {
    String filename = url.getFile();
    if (filename.length() == 0)
      throw new MalformedURLException("No path specified: " + url);
    // If the filename begins with a slash we must cut it for
    // name resolution.
    if (filename.charAt(0) == '/')
      return filename.substring(1);
    return filename;
  }
}