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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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package java.rmi.server;

import java.net.MalformedURLException;

import java.net.URL;

/**

 * <code>RMIClassLoaderSpi</code> is the service provider interface for

 * <code>RMIClassLoader</code>.

 *

 * In particular, an <code>RMIClassLoaderSpi</code> instance provides an

 * implementation of the following static methods of

 * <code>RMIClassLoader</code>:

 *

 * <ul>

 *

 * <li>{@link RMIClassLoader#loadClass(URL,String)}

 * <li>{@link RMIClassLoader#loadClass(String,String)}

 * <li>{@link RMIClassLoader#loadClass(String,String,ClassLoader)}

 * <li>{@link RMIClassLoader#loadProxyClass(String,String[],ClassLoader)}

 * <li>{@link RMIClassLoader#getClassLoader(String)}

 * <li>{@link RMIClassLoader#getClassAnnotation(Class)}

 *

 * </ul>

 *

 * When one of those methods is invoked, its behavior is to delegate

 * to a corresponding method on an instance of this class.

 * The details of how each method delegates to the provider instance is

 * described in the documentation for each particular method.

 * See the documentation for {@link RMIClassLoader} for a description

 * of how a provider instance is chosen.

 *

 * @author      Peter Jones

 * @author      Laird Dornin

 * @see         RMIClassLoader

 * @since       1.4

 */

public abstract class RMIClassLoaderSpi {

    /**

     * Provides the implementation for

     * {@link RMIClassLoader#loadClass(URL,String)},

     * {@link RMIClassLoader#loadClass(String,String)}, and

     * {@link RMIClassLoader#loadClass(String,String,ClassLoader)}.

     *

     * Loads a class from a codebase URL path, optionally using the

     * supplied loader.

     *

     * Typically, a provider implementation will attempt to

     * resolve the named class using the given <code>defaultLoader</code>,

     * if specified, before attempting to resolve the class from the

     * codebase URL path.

     *

     * <p>An implementation of this method must either return a class

     * with the given name or throw an exception.

     *

     * @param   codebase the list of URLs (separated by spaces) to load

     * the class from, or <code>null</code>

     *

     * @param   name the name of the class to load

     *

     * @param   defaultLoader additional contextual class loader

     * to use, or <code>null</code>

     *

     * @return  the <code>Class</code> object representing the loaded class

     *

     * @throws  MalformedURLException if <code>codebase</code> is

     * non-<code>null</code> and contains an invalid URL, or

     * if <code>codebase</code> is <code>null</code> and a provider-specific

     * URL used to load classes is invalid

     *

     * @throws  ClassNotFoundException if a definition for the class

     * could not be found at the specified location

     */

    public abstract Class<?> loadClass(String codebase, String name,

                                       ClassLoader defaultLoader)

        throws MalformedURLException, ClassNotFoundException;

    /**

     * Provides the implementation for

     * {@link RMIClassLoader#loadProxyClass(String,String[],ClassLoader)}.

     *

     * Loads a dynamic proxy class (see {@link java.lang.reflect.Proxy}

     * that implements a set of interfaces with the given names

     * from a codebase URL path, optionally using the supplied loader.

     *

     * <p>An implementation of this method must either return a proxy

     * class that implements the named interfaces or throw an exception.

     *

     * @param   codebase the list of URLs (space-separated) to load

     * classes from, or <code>null</code>

     *

     * @param   interfaces the names of the interfaces for the proxy class

     * to implement

     *

     * @return  a dynamic proxy class that implements the named interfaces

     *

     * @param   defaultLoader additional contextual class loader

     * to use, or <code>null</code>

     *

     * @throws  MalformedURLException if <code>codebase</code> is

     * non-<code>null</code> and contains an invalid URL, or

     * if <code>codebase</code> is <code>null</code> and a provider-specific

     * URL used to load classes is invalid

     *

     * @throws  ClassNotFoundException if a definition for one of

     * the named interfaces could not be found at the specified location,

     * or if creation of the dynamic proxy class failed (such as if

     * {@link java.lang.reflect.Proxy#getProxyClass(ClassLoader,Class[])}

     * would throw an <code>IllegalArgumentException</code> for the given

     * interface list)

     */

    public abstract Class<?> loadProxyClass(String codebase,

                                            String[] interfaces,

                                            ClassLoader defaultLoader)

        throws MalformedURLException, ClassNotFoundException;

    /**

     * Provides the implementation for

     * {@link RMIClassLoader#getClassLoader(String)}.

     *

     * Returns a class loader that loads classes from the given codebase

     * URL path.

     *

     * <p>If there is a security manger, its <code>checkPermission</code>

     * method will be invoked with a

     * <code>RuntimePermission("getClassLoader")</code> permission;

     * this could result in a <code>SecurityException</code>.

     * The implementation of this method may also perform further security

     * checks to verify that the calling context has permission to connect

     * to all of the URLs in the codebase URL path.

     *

     * @param   codebase the list of URLs (space-separated) from which

     * the returned class loader will load classes from, or <code>null</code>

     *

     * @return a class loader that loads classes from the given codebase URL

     * path

     *

     * @throws  MalformedURLException if <code>codebase</code> is

     * non-<code>null</code> and contains an invalid URL, or

     * if <code>codebase</code> is <code>null</code> and a provider-specific

     * URL used to identify the class loader is invalid

     *

     * @throws  SecurityException if there is a security manager and the

     * invocation of its <code>checkPermission</code> method fails, or

     * if the caller does not have permission to connect to all of the

     * URLs in the codebase URL path

     */

    public abstract ClassLoader getClassLoader(String codebase)

        throws MalformedURLException; // SecurityException

    /**

     * Provides the implementation for

     * {@link RMIClassLoader#getClassAnnotation(Class)}.

     *

     * Returns the annotation string (representing a location for

     * the class definition) that RMI will use to annotate the class

     * descriptor when marshalling objects of the given class.

     *

     * @param   cl the class to obtain the annotation for

     *

     * @return  a string to be used to annotate the given class when

     * it gets marshalled, or <code>null</code>

     *

     * @throws  NullPointerException if <code>cl</code> is <code>null</code>

     */

    public abstract String getClassAnnotation(Class<?> cl);

}