001 package org.apache.turbine.pipeline; 002 003 004 /* 005 * Licensed to the Apache Software Foundation (ASF) under one 006 * or more contributor license agreements. See the NOTICE file 007 * distributed with this work for additional information 008 * regarding copyright ownership. The ASF licenses this file 009 * to you under the Apache License, Version 2.0 (the 010 * "License"); you may not use this file except in compliance 011 * with the License. You may obtain a copy of the License at 012 * 013 * http://www.apache.org/licenses/LICENSE-2.0 014 * 015 * Unless required by applicable law or agreed to in writing, 016 * software distributed under the License is distributed on an 017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 018 * KIND, either express or implied. See the License for the 019 * specific language governing permissions and limitations 020 * under the License. 021 */ 022 023 024 import java.io.IOException; 025 026 import org.apache.turbine.util.TurbineException; 027 028 /** 029 * <p>A <b>ValveContext</b> is the mechanism by which a Valve can trigger the 030 * execution of the next Valve in a Pipeline, without having to know anything 031 * about the internal implementation mechanisms. An instance of a class 032 * implementing this interface is passed as a parameter to the 033 * <code>Valve.invoke()</code> method of each executed Valve.</p> 034 * 035 * <p><strong>IMPLEMENTATION NOTE</strong>: It is up to the implementation of 036 * ValveContext to ensure that simultaneous requests being processed (by 037 * separate threads) through the same Pipeline do not interfere with each 038 * other's flow of control.</p> 039 * 040 * @author Craig R. McClanahan 041 * @author Gunnar Rjnning 042 * @author Peter Donald 043 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a> 044 * @version $Revision: 615328 $ $Date: 2008-01-25 21:25:05 +0100 (Fr, 25 Jan 2008) $ 045 */ 046 public interface ValveContext 047 { 048 /** 049 * <p>Cause the <code>invoke()</code> method of the next Valve 050 * that is part of the Pipeline currently being processed (if any) 051 * to be executed, passing on the specified request and response 052 * objects plus this <code>ValveContext</code> instance. 053 * Exceptions thrown by a subsequently executed Valve will be 054 * passed on to our caller.</p> 055 * 056 * <p>If there are no more Valves to be executed, execution of 057 * this method will result in a no op.</p> 058 * 059 * @param data The run-time information, including the servlet 060 * request and response we are processing. 061 * 062 * @exception IOException Thrown by a subsequent Valve. 063 * @exception TurbineException Thrown by a subsequent Valve. 064 * @exception TurbineException No further Valves configured in the 065 * Pipeline currently being processed. 066 */ 067 public void invokeNext(PipelineData data) 068 throws IOException, TurbineException; 069 }