1 /*
2 * Copyright (c) 2000, 2006, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.rmi.server;
27
28 import java.net.MalformedURLException;
29 import java.net.URL;
30
31 /**
32 * <code>RMIClassLoaderSpi</code> is the service provider interface for
33 * <code>RMIClassLoader</code>.
34 *
35 * In particular, an <code>RMIClassLoaderSpi</code> instance provides an
36 * implementation of the following static methods of
37 * <code>RMIClassLoader</code>:
38 *
39 * <ul>
40 *
41 * <li>{@link RMIClassLoader#loadClass(URL,String)}
42 * <li>{@link RMIClassLoader#loadClass(String,String)}
43 * <li>{@link RMIClassLoader#loadClass(String,String,ClassLoader)}
44 * <li>{@link RMIClassLoader#loadProxyClass(String,String[],ClassLoader)}
45 * <li>{@link RMIClassLoader#getClassLoader(String)}
46 * <li>{@link RMIClassLoader#getClassAnnotation(Class)}
47 *
48 * </ul>
49 *
50 * When one of those methods is invoked, its behavior is to delegate
51 * to a corresponding method on an instance of this class.
52 * The details of how each method delegates to the provider instance is
53 * described in the documentation for each particular method.
54 * See the documentation for {@link RMIClassLoader} for a description
55 * of how a provider instance is chosen.
56 *
57 * @author Peter Jones
58 * @author Laird Dornin
59 * @see RMIClassLoader
60 * @since 1.4
61 */
62 public abstract class RMIClassLoaderSpi {
63
64 /**
65 * Provides the implementation for
66 * {@link RMIClassLoader#loadClass(URL,String)},
67 * {@link RMIClassLoader#loadClass(String,String)}, and
68 * {@link RMIClassLoader#loadClass(String,String,ClassLoader)}.
69 *
70 * Loads a class from a codebase URL path, optionally using the
71 * supplied loader.
72 *
73 * Typically, a provider implementation will attempt to
74 * resolve the named class using the given <code>defaultLoader</code>,
75 * if specified, before attempting to resolve the class from the
76 * codebase URL path.
77 *
78 * <p>An implementation of this method must either return a class
79 * with the given name or throw an exception.
80 *
81 * @param codebase the list of URLs (separated by spaces) to load
82 * the class from, or <code>null</code>
83 *
84 * @param name the name of the class to load
85 *
86 * @param defaultLoader additional contextual class loader
87 * to use, or <code>null</code>
88 *
89 * @return the <code>Class</code> object representing the loaded class
90 *
91 * @throws MalformedURLException if <code>codebase</code> is
92 * non-<code>null</code> and contains an invalid URL, or
93 * if <code>codebase</code> is <code>null</code> and a provider-specific
94 * URL used to load classes is invalid
95 *
96 * @throws ClassNotFoundException if a definition for the class
97 * could not be found at the specified location
98 */
99 public abstract Class<?> loadClass(String codebase, String name,
100 ClassLoader defaultLoader)
101 throws MalformedURLException, ClassNotFoundException;
102
103 /**
104 * Provides the implementation for
105 * {@link RMIClassLoader#loadProxyClass(String,String[],ClassLoader)}.
106 *
107 * Loads a dynamic proxy class (see {@link java.lang.reflect.Proxy}
108 * that implements a set of interfaces with the given names
109 * from a codebase URL path, optionally using the supplied loader.
110 *
111 * <p>An implementation of this method must either return a proxy
112 * class that implements the named interfaces or throw an exception.
113 *
114 * @param codebase the list of URLs (space-separated) to load
115 * classes from, or <code>null</code>
116 *
117 * @param interfaces the names of the interfaces for the proxy class
118 * to implement
119 *
120 * @return a dynamic proxy class that implements the named interfaces
121 *
122 * @param defaultLoader additional contextual class loader
123 * to use, or <code>null</code>
124 *
125 * @throws MalformedURLException if <code>codebase</code> is
126 * non-<code>null</code> and contains an invalid URL, or
127 * if <code>codebase</code> is <code>null</code> and a provider-specific
128 * URL used to load classes is invalid
129 *
130 * @throws ClassNotFoundException if a definition for one of
131 * the named interfaces could not be found at the specified location,
132 * or if creation of the dynamic proxy class failed (such as if
133 * {@link java.lang.reflect.Proxy#getProxyClass(ClassLoader,Class[])}
134 * would throw an <code>IllegalArgumentException</code> for the given
135 * interface list)
136 */
137 public abstract Class<?> loadProxyClass(String codebase,
138 String[] interfaces,
139 ClassLoader defaultLoader)
140 throws MalformedURLException, ClassNotFoundException;
141
142 /**
143 * Provides the implementation for
144 * {@link RMIClassLoader#getClassLoader(String)}.
145 *
146 * Returns a class loader that loads classes from the given codebase
147 * URL path.
148 *
149 * <p>If there is a security manger, its <code>checkPermission</code>
150 * method will be invoked with a
151 * <code>RuntimePermission("getClassLoader")</code> permission;
152 * this could result in a <code>SecurityException</code>.
153 * The implementation of this method may also perform further security
154 * checks to verify that the calling context has permission to connect
155 * to all of the URLs in the codebase URL path.
156 *
157 * @param codebase the list of URLs (space-separated) from which
158 * the returned class loader will load classes from, or <code>null</code>
159 *
160 * @return a class loader that loads classes from the given codebase URL
161 * path
162 *
163 * @throws MalformedURLException if <code>codebase</code> is
164 * non-<code>null</code> and contains an invalid URL, or
165 * if <code>codebase</code> is <code>null</code> and a provider-specific
166 * URL used to identify the class loader is invalid
167 *
168 * @throws SecurityException if there is a security manager and the
169 * invocation of its <code>checkPermission</code> method fails, or
170 * if the caller does not have permission to connect to all of the
171 * URLs in the codebase URL path
172 */
173 public abstract ClassLoader getClassLoader(String codebase)
174 throws MalformedURLException; // SecurityException
175
176 /**
177 * Provides the implementation for
178 * {@link RMIClassLoader#getClassAnnotation(Class)}.
179 *
180 * Returns the annotation string (representing a location for
181 * the class definition) that RMI will use to annotate the class
182 * descriptor when marshalling objects of the given class.
183 *
184 * @param cl the class to obtain the annotation for
185 *
186 * @return a string to be used to annotate the given class when
187 * it gets marshalled, or <code>null</code>
188 *
189 * @throws NullPointerException if <code>cl</code> is <code>null</code>
190 */
191 public abstract String getClassAnnotation(Class<?> cl);
192 }
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