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 }