/*
 * $Header: /home/cvs/jakarta-tomcat-catalina/catalina/src/share/org/apache/catalina/ValveContext.java,v 1.1.1.1 2002/07/18 16:47:37 remm Exp $
 * $Revision: 1.1.1.1 $
 * $Date: 2002/07/18 16:47:37 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
 *
 */


package org.apache.catalina;


import java.io.IOException;
import javax.servlet.ServletException;


/**
 * <p>A <b>ValveContext</b> is the mechanism by which a Valve can trigger the
 * execution of the next Valve in a Pipeline, without having to know anything
 * about the internal implementation mechanisms.  An instance of a class
 * implementing this interface is passed as a parameter to the
 * <code>Valve.invoke()</code> method of each executed Valve.</p>
 *
 * <p><strong>IMPLEMENTATION NOTE</strong>: It is up to the implementation of
 * ValveContext to ensure that simultaneous requests being processed (by
 * separate threads) through the same Pipeline do not interfere with each
 * other's flow of control.</p>
 *
 * @author Craig R. McClanahan
 * @author Gunnar Rjnning
 * @author Peter Donald
 * @version $Revision: 1.1.1.1 $ $Date: 2002/07/18 16:47:37 $
 */

public interface ValveContext {


    //-------------------------------------------------------------- Properties


    /**
     * Return descriptive information about this ValveContext implementation.
     */
    public String getInfo();


    //---------------------------------------------------------- Public Methods


    /**
     * Cause the <code>invoke()</code> method of the next Valve that is part of
     * the Pipeline currently being processed (if any) to be executed, passing
     * on the specified request and response objects plus this
     * <code>ValveContext</code> instance.  Exceptions thrown by a subsequently
     * executed Valve (or a Filter or Servlet at the application level) will be
     * passed on to our caller.
     *
     * If there are no more Valves to be executed, an appropriate
     * ServletException will be thrown by this ValveContext.
     *
     * @param request The request currently being processed
     * @param response The response currently being created
     *
     * @exception IOException if thrown by a subsequent Valve, Filter, or
     *  Servlet
     * @exception ServletException if thrown by a subsequent Valve, Filter,
     *  or Servlet
     * @exception ServletException if there are no further Valves configured
     *  in the Pipeline currently being processed
     */
    public void invokeNext(Request request, Response response)
        throws IOException, ServletException;


}
