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.RunData;
027 import org.apache.turbine.util.TurbineException;
028
029 /**
030 * Valve that can be used as the basis of Valve implementations.
031 *
032 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
033 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
034 * @version $Id: AbstractValve.java 757213 2009-03-22 16:43:31Z tv $
035 */
036 public abstract class AbstractValve
037 implements Valve
038 {
039 /**
040 * Initialize this valve for use in a pipeline.
041 *
042 * @throws Exception
043 */
044 public void initialize()
045 throws Exception
046 {
047 // empty
048 }
049
050 /**
051 * @see org.apache.turbine.Valve#invoke(PipelineData, ValveContext)
052 */
053 public abstract void invoke(PipelineData data, ValveContext context)
054 throws IOException, TurbineException;
055
056
057 /**
058 * utility for getting RunData out of the pielineData object.
059 * @param pipelineData
060 * @return
061 */
062 public final RunData getRunData(PipelineData pipelineData)
063 {
064 if(!(pipelineData instanceof RunData)){
065 throw new RuntimeException("Can't cast pipelineData to rundata");
066 }
067 return (RunData)pipelineData;
068 }
069
070 }