| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| |
| package org.apache.catalina; |
| |
| |
| import java.io.IOException; |
| |
| import javax.servlet.ServletException; |
| |
| import org.apache.catalina.comet.CometEvent; |
| import org.apache.catalina.connector.Request; |
| import org.apache.catalina.connector.Response; |
| |
| |
| /** |
| * <p>A <b>Valve</b> is a request processing component associated with a |
| * particular Container. A series of Valves are generally associated with |
| * each other into a Pipeline. The detailed contract for a Valve is included |
| * in the description of the <code>invoke()</code> method below.</p> |
| * |
| * <b>HISTORICAL NOTE</b>: The "Valve" name was assigned to this concept |
| * because a valve is what you use in a real world pipeline to control and/or |
| * modify flows through it. |
| * |
| * @author Craig R. McClanahan |
| * @author Gunnar Rjnning |
| * @author Peter Donald |
| * @version $Id: Valve.java,v 1.1 2011/06/28 21:08:21 rherrmann Exp $ |
| */ |
| |
| public interface Valve { |
| |
| |
| //-------------------------------------------------------------- Properties |
| |
| |
| /** |
| * Return descriptive information about this Valve implementation. |
| */ |
| public String getInfo(); |
| |
| |
| /** |
| * Return the next Valve in the pipeline containing this Valve, if any. |
| */ |
| public Valve getNext(); |
| |
| |
| /** |
| * Set the next Valve in the pipeline containing this Valve. |
| * |
| * @param valve The new next valve, or <code>null</code> if none |
| */ |
| public void setNext(Valve valve); |
| |
| |
| //---------------------------------------------------------- Public Methods |
| |
| |
| /** |
| * Execute a periodic task, such as reloading, etc. This method will be |
| * invoked inside the classloading context of this container. Unexpected |
| * throwables will be caught and logged. |
| */ |
| public void backgroundProcess(); |
| |
| |
| /** |
| * <p>Perform request processing as required by this Valve.</p> |
| * |
| * <p>An individual Valve <b>MAY</b> perform the following actions, in |
| * the specified order:</p> |
| * <ul> |
| * <li>Examine and/or modify the properties of the specified Request and |
| * Response. |
| * <li>Examine the properties of the specified Request, completely generate |
| * the corresponding Response, and return control to the caller. |
| * <li>Examine the properties of the specified Request and Response, wrap |
| * either or both of these objects to supplement their functionality, |
| * and pass them on. |
| * <li>If the corresponding Response was not generated (and control was not |
| * returned, call the next Valve in the pipeline (if there is one) by |
| * executing <code>getNext().invoke()</code>. |
| * <li>Examine, but not modify, the properties of the resulting Response |
| * (which was created by a subsequently invoked Valve or Container). |
| * </ul> |
| * |
| * <p>A Valve <b>MUST NOT</b> do any of the following things:</p> |
| * <ul> |
| * <li>Change request properties that have already been used to direct |
| * the flow of processing control for this request (for instance, |
| * trying to change the virtual host to which a Request should be |
| * sent from a pipeline attached to a Host or Context in the |
| * standard implementation). |
| * <li>Create a completed Response <strong>AND</strong> pass this |
| * Request and Response on to the next Valve in the pipeline. |
| * <li>Consume bytes from the input stream associated with the Request, |
| * unless it is completely generating the response, or wrapping the |
| * request before passing it on. |
| * <li>Modify the HTTP headers included with the Response after the |
| * <code>getNext().invoke()</code> method has returned. |
| * <li>Perform any actions on the output stream associated with the |
| * specified Response after the <code>getNext().invoke()</code> method has |
| * returned. |
| * </ul> |
| * |
| * @param request The servlet request to be processed |
| * @param response The servlet response to be created |
| * |
| * @exception IOException if an input/output error occurs, or is thrown |
| * by a subsequently invoked Valve, Filter, or Servlet |
| * @exception ServletException if a servlet error occurs, or is thrown |
| * by a subsequently invoked Valve, Filter, or Servlet |
| */ |
| public void invoke(Request request, Response response) |
| throws IOException, ServletException; |
| |
| |
| /** |
| * Process a Comet event. |
| * |
| * @param request The servlet request to be processed |
| * @param response The servlet response to be created |
| * |
| * @exception IOException if an input/output error occurs, or is thrown |
| * by a subsequently invoked Valve, Filter, or Servlet |
| * @exception ServletException if a servlet error occurs, or is thrown |
| * by a subsequently invoked Valve, Filter, or Servlet |
| */ |
| public void event(Request request, Response response, CometEvent event) |
| throws IOException, ServletException; |
| |
| |
| public boolean isAsyncSupported(); |
| |
| |
| } |