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package java.rmi.server;

import java.net.MalformedURLException;
import java.net.URL;


RMIClassLoaderSpi is the service provider interface for
RMIClassLoader.
In particular, an RMIClassLoaderSpi instance provides an
implementation of the following static methods of
RMIClassLoader:
 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 RMIClassLoader for a description of how a provider instance is chosen. 
Author:     Peter Jones,      Laird Dornin
See Also:
Since:      1.4
/**
 * <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 RMIClassLoader.loadClass(URL, String), RMIClassLoader.loadClass(String, String), and 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 defaultLoader,
if specified, before attempting to resolve the class from the
codebase URL path.

An implementation of this method must either return a class
with the given name or throw an exception.

Params:
  • codebase – the list of URLs (separated by spaces) to load
the class from, or null
  • name – the name of the class to load
  • defaultLoader – additional contextual class loader
to use, or null
Throws:
  • MalformedURLException – if codebase is
non-null and contains an invalid URL, or
if codebase is null and a provider-specific
URL used to load classes is invalid
  • ClassNotFoundException – if a definition for the class
could not be found at the specified location
Returns: the Class object representing the loaded class
/**
     * 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 RMIClassLoader.loadProxyClass(String, String[], ClassLoader). Loads a dynamic proxy class (see Proxy that implements a set of interfaces with the given names from a codebase URL path, optionally using the supplied loader. 
An implementation of this method must either return a proxy
class that implements the named interfaces or throw an exception.

Params:
  • codebase – the list of URLs (space-separated) to load
classes from, or null
  • interfaces – the names of the interfaces for the proxy class
to implement
  • defaultLoader – additional contextual class loader
to use, or null
Throws:
  • MalformedURLException – if codebase is
non-null and contains an invalid URL, or
if codebase is null and a provider-specific
URL used to load classes is invalid
  • 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 Proxy.getProxyClass(ClassLoader, Class<?>[]) would throw an IllegalArgumentException for the given
interface list)
Returns: a dynamic proxy class that implements the named interfaces
/**
     * 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 RMIClassLoader.getClassLoader(String). Returns a class loader that loads classes from the given codebase URL path. 
If there is a security manger, its checkPermission
method will be invoked with a
RuntimePermission("getClassLoader") permission;
this could result in a SecurityException.
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.

Params:
  • codebase – the list of URLs (space-separated) from which
the returned class loader will load classes from, or null
Throws:
  • MalformedURLException – if codebase is
non-null and contains an invalid URL, or
if codebase is null and a provider-specific
URL used to identify the class loader is invalid
  • SecurityException – if there is a security manager and the
invocation of its checkPermission method fails, or
if the caller does not have permission to connect to all of the
URLs in the codebase URL path
Returns:a class loader that loads classes from the given codebase URL
path
/**
     * 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 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. 
Params:
  • cl – the class to obtain the annotation for
Throws:
Returns: a string to be used to annotate the given class when
it gets marshalled, or null
/**
     * 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);
}