/*
 * @(#)MBeanServerInterceptor.java	1.16 03/12/19
 * 
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.jmx.interceptor;

import java.util.Set;

// RI import
import javax.management.DynamicMBean;
import javax.management.AttributeNotFoundException;
import javax.management.MBeanException; 
import javax.management.ReflectionException;
import javax.management.MBeanAttributeInfo;
import javax.management.MBeanInfo;
import javax.management.QueryExp;
import javax.management.NotificationListener;
import javax.management.NotificationFilter;
import javax.management.ListenerNotFoundException;
import javax.management.IntrospectionException;
import javax.management.OperationsException;
import javax.management.MBeanNotificationInfo;
import javax.management.JMRuntimeException;
import javax.management.InstanceNotFoundException;
import javax.management.NotCompliantMBeanException;
import javax.management.MBeanRegistrationException;
import javax.management.InstanceAlreadyExistsException;
import javax.management.InvalidAttributeValueException;
import javax.management.ObjectName;
import javax.management.ObjectInstance;
import javax.management.Attribute;
import javax.management.AttributeList;
import javax.management.RuntimeOperationsException;
import javax.management.MBeanServerConnection; 
import javax.management.MBeanServerDelegate; 
import javax.management.loading.ClassLoaderRepository;

/**
 * <p>This interface specifies the behavior to be implemented by an
 * MBean Server Interceptor.  An MBean Server Interceptor has
 * essentially the same interface as an MBean Server.  An MBean Server
 * forwards received requests to its default interceptor, which may
 * handle them itself or forward them to other interceptors.  The
 * default interceptor may be changed via the {@link
 * com.sun.jmx.mbeanserver.SunJmxMBeanServer#setMBeanServerInterceptor} 
 * method.</p>
 *
 * <p>The initial default interceptor provides the standard MBean
 * Server behaviour.  It handles a collection of named MBeans, each
 * represented by a Java object.  A replacement default interceptor
 * may build on this behaviour, for instance by adding logging or
 * security checks, before forwarding requests to the initial default
 * interceptor.  Or, it may route each request to one of a number of
 * sub-interceptors, for instance based on the {@link ObjectName} in
 * the request.</p>
 *
 * <p>An interceptor, default or not, need not implement MBeans as
 * Java objects, in the way that the initial default interceptor does.
 * It may instead implement <em>virtual MBeans</em>, which do not
 * exist as Java objects when they are not in use.  For example, these
 * MBeans could be implemented by forwarding requests to a database,
 * or to a remote MBean server, or by performing system calls to query
 * or modify system resources.</p>
 *
 * @since 1.5
 */
public interface MBeanServerInterceptor extends MBeanServerConnection {
    /**
     * Instantiates and registers an MBean in the MBean server.  The
     * MBean server will use its {@link
     * javax.management.loading.ClassLoaderRepository Default Loader
     * Repository} to load the class of the MBean.  An object name is
     * associated to the MBean.  If the object name given is null, the
     * MBean must provide its own name by implementing the {@link
     * javax.management.MBeanRegistration MBeanRegistration} interface
     * and returning the name from the {@link
     * javax.management.MBeanRegistration#preRegister preRegister} method.
     *
     * @param className The class name of the MBean to be instantiated.
     * @param name The object name of the MBean. May be null.
     * @param params An array containing the parameters of the
     * constructor to be invoked.
     * @param signature An array containing the signature of the
     * constructor to be invoked.
     *
     * @return An <CODE>ObjectInstance</CODE>, containing the
     * <CODE>ObjectName</CODE> and the Java class name of the newly
     * instantiated MBean.
     *
     * @exception ReflectionException Wraps a
     * <CODE>java.lang.ClassNotFoundException</CODE> or a
     * <CODE>java.lang.Exception</CODE> that occurred when trying to
     * invoke the MBean's constructor.
     * @exception InstanceAlreadyExistsException The MBean is already
     * under the control of the MBean server.
     * @exception MBeanRegistrationException The
     * <CODE>preRegister</CODE> (<CODE>MBeanRegistration</CODE>
     * interface) method of the MBean has thrown an exception. The
     * MBean will not be registered.
     * @exception MBeanException The constructor of the MBean has
     * thrown an exception
     * @exception RuntimeOperationsException Wraps a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The className
     * passed in parameter is null, the <CODE>ObjectName</CODE> passed
     * in parameter contains a pattern or no <CODE>ObjectName</CODE>
     * is specified for the MBean.
     */
    public ObjectInstance createMBean(String className, ObjectName name,
				      Object params[], String signature[]) 
	    throws ReflectionException, InstanceAlreadyExistsException,
	    	   MBeanRegistrationException, MBeanException,
	    	   NotCompliantMBeanException;

    /**
     * Instantiates and registers an MBean in the MBean server.  The
     * class loader to be used is identified by its object name. An
     * object name is associated to the MBean. If the object name of
     * the loader is not specified, the ClassLoader that loaded the
     * MBean server will be used.  If the MBean object name given is
     * null, the MBean must provide its own name by implementing the
     * {@link javax.management.MBeanRegistration MBeanRegistration}
     * interface and returning the name from the {@link
     * javax.management.MBeanRegistration#preRegister preRegister} method.
     *
     * @param className The class name of the MBean to be instantiated.
     * @param name The object name of the MBean. May be null.
     * @param params An array containing the parameters of the
     * constructor to be invoked.
     * @param signature An array containing the signature of the
     * constructor to be invoked.
     * @param loaderName The object name of the class loader to be used.
     *
     * @return An <CODE>ObjectInstance</CODE>, containing the
     * <CODE>ObjectName</CODE> and the Java class name of the newly
     * instantiated MBean.
     *
     * @exception ReflectionException Wraps a
     * <CODE>java.lang.ClassNotFoundException</CODE> or a
     * <CODE>java.lang.Exception</CODE> that occurred when trying to
     * invoke the MBean's constructor.
     * @exception InstanceAlreadyExistsException The MBean is already
     * under the control of the MBean server.
     * @exception MBeanRegistrationException The
     * <CODE>preRegister</CODE> (<CODE>MBeanRegistration</CODE>
     * interface) method of the MBean has thrown an exception. The
     * MBean will not be registered.
     * @exception MBeanException The constructor of the MBean has
     * thrown an exception
     * @exception InstanceNotFoundException The specified class loader
     * is not registered in the MBean server.
     * @exception RuntimeOperationsException Wraps a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The className
     * passed in parameter is null, the <CODE>ObjectName</CODE> passed
     * in parameter contains a pattern or no <CODE>ObjectName</CODE>
     * is specified for the MBean.
     *
     */
    public ObjectInstance createMBean(String className, ObjectName name,
				      ObjectName loaderName, Object params[],
				      String signature[]) 
	    throws ReflectionException, InstanceAlreadyExistsException,
	    	   MBeanRegistrationException, MBeanException,
	    	   NotCompliantMBeanException, InstanceNotFoundException;

    /**
     * Registers a pre-existing object as an MBean with the MBean
     * server. If the object name given is null, the MBean must
     * provide its own name by implementing the {@link
     * javax.management.MBeanRegistration MBeanRegistration} interface
     * and returning the name from the {@link
     * javax.management.MBeanRegistration#preRegister preRegister} method.
     *
     * @param object The  MBean to be registered as an MBean.	  
     * @param name The object name of the MBean. May be null.
     *
     * @return The <CODE>ObjectInstance</CODE> for the MBean that has
     * been registered.
     *
     * @exception InstanceAlreadyExistsException The MBean is already
     * under the control of the MBean server.
     * @exception MBeanRegistrationException The
     * <CODE>preRegister</CODE> (<CODE>MBeanRegistration</CODE>
     * interface) method of the MBean has thrown an exception. The
     * MBean will not be registered.
     * @exception NotCompliantMBeanException This object is not a JMX
     * compliant MBean
     * @exception RuntimeOperationsException Wraps a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The object
     * passed in parameter is null or no object name is specified.
     */
    public ObjectInstance registerMBean(Object object, ObjectName name)
	    throws InstanceAlreadyExistsException, MBeanRegistrationException,
		   NotCompliantMBeanException;

    /**
     * Unregisters an MBean from the MBean server. The MBean is
     * identified by its object name. Once the method has been
     * invoked, the MBean may no longer be accessed by its object
     * name.
     *
     * @param name The object name of the MBean to be unregistered.
     *
     * @exception InstanceNotFoundException The MBean specified is not
     * registered in the MBean server.
     * @exception MBeanRegistrationException The preDeregister
     * ((<CODE>MBeanRegistration</CODE> interface) method of the MBean
     * has thrown an exception.
     * @exception RuntimeOperationsException Wraps a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The object
     * name in parameter is null or the MBean you are when trying to
     * unregister is the {@link javax.management.MBeanServerDelegate
     * MBeanServerDelegate} MBean.
     *
     */
    public void unregisterMBean(ObjectName name)
	    throws InstanceNotFoundException, MBeanRegistrationException;

    /**
     * Gets the <CODE>ObjectInstance</CODE> for a given MBean
     * registered with the MBean server.
     *
     * @param name The object name of the MBean.
     *
     * @return The <CODE>ObjectInstance</CODE> associated to the MBean
     * specified by <VAR>name</VAR>.
     *
     * @exception InstanceNotFoundException The MBean specified is not
     * registered in the MBean server.
     */
    public ObjectInstance getObjectInstance(ObjectName name)
	    throws InstanceNotFoundException;

    /**
     * Gets MBeans controlled by the MBean server. This method allows
     * any of the following to be obtained: All MBeans, a set of
     * MBeans specified by pattern matching on the
     * <CODE>ObjectName</CODE> and/or a Query expression, a specific
     * MBean. When the object name is null or no domain and key
     * properties are specified, all objects are to be selected (and
     * filtered if a query is specified). It returns the set of
     * <CODE>ObjectInstance</CODE> objects (containing the
     * <CODE>ObjectName</CODE> and the Java Class name) for the
     * selected MBeans.
     *
     * @param name The object name pattern identifying the MBeans to
     * be retrieved. If null or no domain and key properties are
     * specified, all the MBeans registered will be retrieved.
     * @param query The query expression to be applied for selecting
     * MBeans. If null no query expression will be applied for
     * selecting MBeans.
     *
     * @return A set containing the <CODE>ObjectInstance</CODE>
     * objects for the selected MBeans.  If no MBean satisfies the
     * query an empty list is returned.
     */
    public Set queryMBeans(ObjectName name, QueryExp query);

    /**
     * Gets the names of MBeans controlled by the MBean server. This
     * method enables any of the following to be obtained: The names
     * of all MBeans, the names of a set of MBeans specified by
     * pattern matching on the <CODE>ObjectName</CODE> and/or a Query
     * expression, a specific MBean name (equivalent to testing
     * whether an MBean is registered). When the object name is null
     * or no domain and key properties are specified, all objects are
     * selected (and filtered if a query is specified). It returns the
     * set of ObjectNames for the MBeans selected.
     *
     * @param name The object name pattern identifying the MBean names
     * to be retrieved. If null oror no domain and key properties are
     * specified, the name of all registered MBeans will be retrieved.
     * @param query The query expression to be applied for selecting
     * MBeans. If null no query expression will be applied for
     * selecting MBeans.
     *
     * @return A set containing the ObjectNames for the MBeans
     * selected.  If no MBean satisfies the query, an empty list is
     * returned.
     */
    public Set queryNames(ObjectName name, QueryExp query);

    /**
     * Checks whether an MBean, identified by its object name, is
     * already registered with the MBean server.
     *
     * @param name The object name of the MBean to be checked.
     *
     * @return True if the MBean is already registered in the MBean
     * server, false otherwise.
     *
     * @exception RuntimeOperationsException Wraps a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The object
     * name in parameter is null.
     */
    public boolean isRegistered(ObjectName name);

    /**
     * Returns the number of MBeans registered in the MBean server.
     */
    public Integer getMBeanCount();

    /**
     * Gets the value of a specific attribute of a named MBean. The MBean
     * is identified by its object name.
     *
     * @param name The object name of the MBean from which the
     * attribute is to be retrieved.
     * @param attribute A String specifying the name of the attribute
     * to be retrieved.
     *
     * @return	The value of the retrieved attribute.
     *
     * @exception AttributeNotFoundException The attribute specified
     * is not accessible in the MBean.
     * @exception MBeanException Wraps an exception thrown by the
     * MBean's getter.
     * @exception InstanceNotFoundException The MBean specified is not
     * registered in the MBean server.
     * @exception ReflectionException Wraps a
     * <CODE>java.lang.Exception</CODE> thrown when trying to invoke
     * the setter.
     * @exception RuntimeOperationsException Wraps a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The object
     * name in parameter is null or the attribute in parameter is
     * null.
     */
    public Object getAttribute(ObjectName name, String attribute)
	    throws MBeanException, AttributeNotFoundException,
	    	   InstanceNotFoundException, ReflectionException;

    /**
     * Enables the values of several attributes of a named MBean. The MBean
     * is identified by its object name.
     *
     * @param name The object name of the MBean from which the
     * attributes are retrieved.
     * @param attributes A list of the attributes to be retrieved.
     *
     * @return The list of the retrieved attributes.
     *
     * @exception InstanceNotFoundException The MBean specified is not
     * registered in the MBean server.
     * @exception ReflectionException An exception occurred when
     * trying to invoke the getAttributes method of a Dynamic MBean.
     * @exception RuntimeOperationsException Wrap a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The object
     * name in parameter is null or attributes in parameter is null.
     */
    public AttributeList getAttributes(ObjectName name, String[] attributes)
	    throws InstanceNotFoundException, ReflectionException;

    /**
     * Sets the value of a specific attribute of a named MBean. The MBean
     * is identified by its object name.
     *
     * @param name The name of the MBean within which the attribute is
     * to be set.
     * @param attribute The identification of the attribute to be set
     * and the value it is to be set to.
     *
     * @return The value of the attribute that has been set.
     *
     * @exception InstanceNotFoundException The MBean specified is not
     * registered in the MBean server.
     * @exception AttributeNotFoundException The attribute specified
     * is not accessible in the MBean.
     * @exception InvalidAttributeValueException The value specified
     * for the attribute is not valid.
     * @exception MBeanException Wraps an exception thrown by the
     * MBean's setter.
     * @exception ReflectionException Wraps a
     * <CODE>java.lang.Exception</CODE> thrown when trying to invoke
     * the setter.
     * @exception RuntimeOperationsException Wraps a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The object
     * name in parameter is null or the attribute in parameter is
     * null.
     */
    public void setAttribute(ObjectName name, Attribute attribute)
	    throws InstanceNotFoundException, AttributeNotFoundException,
		   InvalidAttributeValueException, MBeanException, 
		   ReflectionException;



    /**
     * Sets the values of several attributes of a named MBean. The MBean is
     * identified by its object name.
     *
     * @param name The object name of the MBean within which the
     * attributes are to be set.
     * @param attributes A list of attributes: The identification of
     * the attributes to be set and the values they are to be set to.
     *
     * @return The list of attributes that were set, with their new
     * values.
     *
     * @exception InstanceNotFoundException The MBean specified is not
     * registered in the MBean server.
     * @exception ReflectionException An exception occurred when
     * trying to invoke the getAttributes method of a Dynamic MBean.
     * @exception RuntimeOperationsException Wraps a
     * <CODE>java.lang.IllegalArgumentException</CODE>: The object
     * name in parameter is null or attributes in parameter is null.
     */
    public AttributeList setAttributes(ObjectName name,
				       AttributeList attributes)
	throws InstanceNotFoundException, ReflectionException;

    /**
     * Invokes an operation on an MBean.
     *
     * @param name The object name of the MBean on which the method is
     * to be invoked.
     * @param operationName The name of the operation to be invoked.
     * @param params An array containing the parameters to be set when
     * the operation is invoked
     * @param signature An array containing the signature of the
     * operation. The class objects will be loaded using the same
     * class loader as the one used for loading the MBean on which the
     * operation was invoked.
     *
     * @return The object returned by the operation, which represents
     * the result ofinvoking the operation on the MBean specified.
     *
     * @exception InstanceNotFoundException The MBean specified is not
     * registered in the MBean server.
     * @exception MBeanException Wraps an exception thrown by the
     * MBean's invoked method.
     * @exception ReflectionException Wraps a
     * <CODE>java.lang.Exception</CODE> thrown while trying to invoke
     * the method.
     */
    public Object invoke(ObjectName name, String operationName,
			 Object params[], String signature[])
	    throws InstanceNotFoundException, MBeanException,
		   ReflectionException;
 
    /**
     * Returns the default domain used for naming the MBean.
     * The default domain name is used as the domain part in the ObjectName
     * of MBeans if no domain is specified by the user.
     */
    public String getDefaultDomain();

    /**
     * Returns the list of domains in which any MBean is currently
     * registered.
     */
    public String[] getDomains();

    /**
     * <p>Adds a listener to a registered MBean.</p>
     *
     * <P> A notification emitted by an MBean will be forwarded by the
     * MBeanServer to the listener.  If the source of the notification
     * is a reference to an MBean object, the MBean server will replace it
     * by that MBean's ObjectName.  Otherwise the source is unchanged.
     *
     * @param name The name of the MBean on which the listener should
     * be added.
     * @param listener The listener object which will handle the
     * notifications emitted by the registered MBean.
     * @param filter The filter object. If filter is null, no
     * filtering will be performed before handling notifications.
     * @param handback The context to be sent to the listener when a
     * notification is emitted.
     *
     * @exception InstanceNotFoundException The MBean name provided
     * does not match any of the registered MBeans.
     */
    public void addNotificationListener(ObjectName name,
					NotificationListener listener,
					NotificationFilter filter,
					Object handback)
	    throws InstanceNotFoundException;


    /**
     * <p>Adds a listener to a registered MBean.</p>
     *
     * <p>A notification emitted by an MBean will be forwarded by the
     * MBeanServer to the listener.  If the source of the notification
     * is a reference to an MBean object, the MBean server will
     * replace it by that MBean's ObjectName.  Otherwise the source is
     * unchanged.</p>
     *
     * <p>The listener object that receives notifications is the one
     * that is registered with the given name at the time this method
     * is called.  Even if it is subsequently unregistered, it will
     * continue to receive notifications.</p>
     *
     * @param name The name of the MBean on which the listener should
     * be added.
     * @param listener The object name of the listener which will
     * handle the notifications emitted by the registered MBean.
     * @param filter The filter object. If filter is null, no
     * filtering will be performed before handling notifications.
     * @param handback The context to be sent to the listener when a
     * notification is emitted.
     *
     * @exception InstanceNotFoundException The MBean name of the
     * notification listener or of the notification broadcaster does
     * not match any of the registered MBeans.
     * @exception RuntimeOperationsException Wraps an {@link
     * IllegalArgumentException}.  The MBean named by
     * <code>listener</code> exists but does not implement the {@link
     * NotificationListener} interface.
     * @exception IOException A communication problem occurred when
     * talking to the MBean server.
     */
    public void addNotificationListener(ObjectName name,
					ObjectName listener,
					NotificationFilter filter,
					Object handback)
	    throws InstanceNotFoundException;

    /**
     * Removes a listener from a registered MBean.
     *
     * <P> If the listener is registered more than once, perhaps with
     * different filters or callbacks, this method will remove all
     * those registrations.
     *
     * @param name The name of the MBean on which the listener should
     * be removed.
     * @param listener The object name of the listener to be removed.
     *
     * @exception InstanceNotFoundException The MBean name provided
     * does not match any of the registered MBeans.
     * @exception ListenerNotFoundException The listener is not
     * registered in the MBean.
     */
    public void removeNotificationListener(ObjectName name,
					   ObjectName listener) 
	throws InstanceNotFoundException, ListenerNotFoundException;

    /**
     * <p>Removes a listener from a registered MBean.</p>
     *
     * <p>The MBean must have a listener that exactly matches the
     * given <code>listener</code>, <code>filter</code>, and
     * <code>handback</code> parameters.  If there is more than one
     * such listener, only one is removed.</p>
     *
     * <p>The <code>filter</code> and <code>handback</code> parameters
     * may be null if and only if they are null in a listener to be
     * removed.</p>
     *
     * @param name The name of the MBean on which the listener should
     * be removed.
     * @param listener A listener that was previously added to this
     * MBean.
     * @param filter The filter that was specified when the listener
     * was added.
     * @param handback The handback that was specified when the
     * listener was added.
     *
     * @exception InstanceNotFoundException The MBean name provided
     * does not match any of the registered MBeans.
     * @exception ListenerNotFoundException The listener is not
     * registered in the MBean, or it is not registered with the given
     * filter and handback.
     */
    public void removeNotificationListener(ObjectName name,
					   ObjectName listener,
					   NotificationFilter filter,
					   Object handback)
	    throws InstanceNotFoundException, ListenerNotFoundException;


    /**
     * <p>Removes a listener from a registered MBean.</p>
     *
     * <P> If the listener is registered more than once, perhaps with
     * different filters or callbacks, this method will remove all
     * those registrations.
     *
     * @param name The name of the MBean on which the listener should
     * be removed.
     * @param listener The listener object which will handle the
     * notifications emitted by the registered MBean.
     *
     * @exception InstanceNotFoundException The MBean name provided
     * does not match any of the registered MBeans.
     * @exception ListenerNotFoundException The listener is not
     * registered in the MBean.
     */
    public void removeNotificationListener(ObjectName name,
					   NotificationListener listener)
	    throws InstanceNotFoundException, ListenerNotFoundException;

    /**
     * <p>Removes a listener from a registered MBean.</p>
     *
     * <p>The MBean must have a listener that exactly matches the
     * given <code>listener</code>, <code>filter</code>, and
     * <code>handback</code> parameters.  If there is more than one
     * such listener, only one is removed.</p>
     *
     * <p>The <code>filter</code> and <code>handback</code> parameters
     * may be null if and only if they are null in a listener to be
     * removed.</p>
     *
     * @param name The name of the MBean on which the listener should
     * be removed.
     * @param listener A listener that was previously added to this
     * MBean.
     * @param filter The filter that was specified when the listener
     * was added.
     * @param handback The handback that was specified when the
     * listener was added.
     *
     * @exception InstanceNotFoundException The MBean name provided
     * does not match any of the registered MBeans.
     * @exception ListenerNotFoundException The listener is not
     * registered in the MBean, or it is not registered with the given
     * filter and handback.
     */
    public void removeNotificationListener(ObjectName name,
					   NotificationListener listener,
					   NotificationFilter filter,
					   Object handback)
	    throws InstanceNotFoundException, ListenerNotFoundException;

    /**
     * This method discovers the attributes and operations that an
     * MBean exposes for management.
     *
     * @param name The name of the MBean to analyze
     *
     * @return An instance of <CODE>MBeanInfo</CODE> allowing the
     * retrieval of all attributes and operations of this MBean.
     *
     * @exception IntrospectionException An exception occured during
     * introspection.
     * @exception InstanceNotFoundException The MBean specified was
     * not found.
     * @exception ReflectionException An exception occurred when
     * trying to invoke the getMBeanInfo of a Dynamic MBean.
     */
    public MBeanInfo getMBeanInfo(ObjectName name)
	    throws InstanceNotFoundException, IntrospectionException,
	    	   ReflectionException;

 
    /**
     * Returns true if the MBean specified is an instance of the
     * specified class, false otherwise.
     * 
     * @param name The <CODE>ObjectName</CODE> of the MBean.
     * @param className The name of the class.
     *
     * @return true if the MBean specified is an instance of the
     * specified class, false otherwise.
     *
     * @exception InstanceNotFoundException The MBean specified is not
     * registered in the MBean server.
     */
    public boolean isInstanceOf(ObjectName name, String className)
	    throws InstanceNotFoundException;
 
    /**
     * <p>Return the {@link java.lang.ClassLoader} that was used for
     * loading the class of the named MBean.
     * @param mbeanName The ObjectName of the MBean.
     * @return The ClassLoader used for that MBean.
     * @exception InstanceNotFoundException if the named MBean is not found.
     */
    public ClassLoader getClassLoaderFor(ObjectName mbeanName)
	throws InstanceNotFoundException;

    /**
     * <p>Return the named {@link java.lang.ClassLoader}.
     * @param loaderName The ObjectName of the ClassLoader.
     * @return The named ClassLoader.
     * @exception InstanceNotFoundException if the named ClassLoader is 
     * not found.
     */
    public ClassLoader getClassLoader(ObjectName loaderName)
	throws InstanceNotFoundException;

}
