001 /* RMIClassLoader.java --
002 Copyright (c) 1996, 1997, 1998, 1999, 2002, 2003, 2004
003 Free Software Foundation, Inc.
004
005 This file is part of GNU Classpath.
006
007 GNU Classpath is free software; you can redistribute it and/or modify
008 it under the terms of the GNU General Public License as published by
009 the Free Software Foundation; either version 2, or (at your option)
010 any later version.
011
012 GNU Classpath is distributed in the hope that it will be useful, but
013 WITHOUT ANY WARRANTY; without even the implied warranty of
014 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 General Public License for more details.
016
017 You should have received a copy of the GNU General Public License
018 along with GNU Classpath; see the file COPYING. If not, write to the
019 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
020 02110-1301 USA.
021
022 Linking this library statically or dynamically with other modules is
023 making a combined work based on this library. Thus, the terms and
024 conditions of the GNU General Public License cover the whole
025 combination.
026
027 As a special exception, the copyright holders of this library give you
028 permission to link this library with independent modules to produce an
029 executable, regardless of the license terms of these independent
030 modules, and to copy and distribute the resulting executable under
031 terms of your choice, provided that you also meet, for each linked
032 independent module, the terms and conditions of the license of that
033 module. An independent module is a module which is not derived from
034 or based on this library. If you modify this library, you may extend
035 this exception to your version of the library, but you are not
036 obligated to do so. If you do not wish to do so, delete this
037 exception statement from your version. */
038
039 package java.rmi.server;
040
041 import gnu.classpath.ServiceFactory;
042 import gnu.classpath.SystemProperties;
043 import gnu.java.rmi.server.RMIClassLoaderImpl;
044
045 import java.net.MalformedURLException;
046 import java.net.URL;
047 import java.util.Iterator;
048
049 /**
050 * This class provides a set of public static utility methods for supporting
051 * network-based class loading in RMI. These methods are called by RMI's
052 * internal marshal streams to implement the dynamic class loading of types for
053 * RMI parameters and return values.
054 * @since 1.1
055 */
056 public class RMIClassLoader
057 {
058 /**
059 * This class isn't intended to be instantiated.
060 */
061 private RMIClassLoader() {}
062
063 /**
064 * @deprecated
065 */
066 public static Class<?> loadClass(String name)
067 throws MalformedURLException, ClassNotFoundException
068 {
069 return loadClass("", name);
070 }
071
072 public static Class<?> loadClass(String codebase, String name)
073 throws MalformedURLException, ClassNotFoundException
074 {
075 RMIClassLoaderSpi spi = getProviderInstance();
076 if (spi == null)
077 spi = getDefaultProviderInstance();
078 return spi.loadClass(codebase, name, null);
079 }
080
081 public static Class<?> loadClass(String codebase, String name,
082 ClassLoader defaultLoader)
083 throws MalformedURLException, ClassNotFoundException
084 {
085 RMIClassLoaderSpi spi = getProviderInstance();
086 if (spi == null)
087 spi = getDefaultProviderInstance();
088 return spi.loadClass(codebase, name, defaultLoader);
089 }
090
091 public static Class<?> loadProxyClass (String codeBase, String[] interfaces,
092 ClassLoader defaultLoader)
093 throws MalformedURLException, ClassNotFoundException
094 {
095 RMIClassLoaderSpi spi = getProviderInstance();
096 if (spi == null)
097 spi = getDefaultProviderInstance();
098 return spi.loadProxyClass(codeBase, interfaces, defaultLoader);
099 }
100
101 /**
102 * Loads a class from <code>codeBase</code>.
103 *
104 * This method delegates to
105 * {@link RMIClassLoaderSpi#loadClass(String, String, ClassLoader)} and
106 * passes <code>codeBase.toString()</code> as first argument,
107 * <code>name</code> as second argument and <code>null</code> as third
108 * argument.
109 *
110 * @param codeBase the code base from which to load the class
111 * @param name the name of the class
112 *
113 * @return the loaded class
114 *
115 * @throws MalformedURLException if the URL is not well formed
116 * @throws ClassNotFoundException if the requested class cannot be found
117 */
118 public static Class<?> loadClass(URL codeBase, String name)
119 throws MalformedURLException, ClassNotFoundException
120 {
121 RMIClassLoaderSpi spi = getProviderInstance();
122 if (spi == null)
123 spi = getDefaultProviderInstance();
124 return spi.loadClass(codeBase.toString(), name, null);
125 }
126
127 /**
128 * Gets a classloader for the given codebase and with the current
129 * context classloader as parent.
130 *
131 * @param codebase
132 *
133 * @return a classloader for the given codebase
134 *
135 * @throws MalformedURLException if the codebase contains a malformed URL
136 */
137 public static ClassLoader getClassLoader(String codebase)
138 throws MalformedURLException
139 {
140 RMIClassLoaderSpi spi = getProviderInstance();
141 if (spi == null)
142 spi = getDefaultProviderInstance();
143 return spi.getClassLoader(codebase);
144 }
145
146 /**
147 * Returns a string representation of the network location where a remote
148 * endpoint can get the class-definition of the given class.
149 *
150 * @param cl
151 *
152 * @return a space seperated list of URLs where the class-definition
153 * of cl may be found
154 */
155 public static String getClassAnnotation(Class<?> cl)
156 {
157 RMIClassLoaderSpi spi = getProviderInstance();
158 if (spi == null)
159 spi = getDefaultProviderInstance();
160 return spi.getClassAnnotation(cl);
161 }
162
163 /**
164 * @deprecated
165 */
166 public static Object getSecurityContext (ClassLoader loader)
167 {
168 throw new Error ("Not implemented");
169 }
170
171 /**
172 * Returns the default service provider for <code>RMIClassLoader</code>.
173 *
174 * @return the default provider for <code>RMIClassLoader</code>
175 */
176 public static RMIClassLoaderSpi getDefaultProviderInstance()
177 {
178 return RMIClassLoaderImpl.getInstance();
179 }
180
181 /**
182 * Chooses, instantiates and returns a service provider.
183 *
184 * @return a service provider
185 */
186 private static RMIClassLoaderSpi getProviderInstance()
187 {
188 // If the user asked for the default, return it. We do a special
189 // check here because our standard service lookup function does not
190 // handle this -- nor should it.
191 String prop = SystemProperties.getProperty("java.rmi.server.RMIClassLoaderSpi");
192 if ("default".equals(prop))
193 return null;
194 Iterator it = ServiceFactory.lookupProviders(RMIClassLoaderSpi.class,
195 null);
196 if (it == null || ! it.hasNext())
197 return null;
198 // FIXME: the spec says we ought to throw an Error of some kind if
199 // the specified provider is not suitable for some reason. However
200 // our service factory simply logs the problem and moves on to the next
201 // provider in this situation.
202 return (RMIClassLoaderSpi) it.next();
203 }
204 }