001package 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
024import java.io.IOException;
025
026import org.apache.turbine.util.RunData;
027import 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 1773378 2016-12-09 13:19:59Z tv $
035 */
036public abstract class AbstractValve
037    implements Valve
038{
039    /**
040     * Initialize this valve for use in a pipeline.
041     *
042     * @throws Exception if initialization fails
043     */
044    @Override
045    public void initialize()
046        throws Exception
047    {
048        // empty
049    }
050
051    /**
052     * @see org.apache.turbine.pipeline.Valve#invoke(PipelineData, ValveContext)
053     */
054    @Override
055    public abstract void invoke(PipelineData data, ValveContext context)
056        throws IOException, TurbineException;
057
058
059    /**
060     * Utility for getting RunData out of the pipelineData object.
061     *
062     * @param pipelineData Turbine request data
063     * @return the RunData object extracted from pipelineData
064     */
065    public final RunData getRunData(PipelineData pipelineData)
066    {
067        if(!(pipelineData instanceof RunData))
068        {
069            throw new RuntimeException("Can't cast pipelineData to rundata");
070        }
071        return (RunData)pipelineData;
072    }
073}