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    1   package org.apache.turbine.pipeline;
    2
    3
    4   /*
    5    * Licensed to the Apache Software Foundation (ASF) under one
    6    * or more contributor license agreements.  See the NOTICE file
    7    * distributed with this work for additional information
    8    * regarding copyright ownership.  The ASF licenses this file
    9    * to you under the Apache License, Version 2.0 (the
    10   * "License"); you may not use this file except in compliance
    11   * with the License.  You may obtain a copy of the License at
    12   *
    13   *   http://www.apache.org/licenses/LICENSE-2.0
    14   *
    15   * Unless required by applicable law or agreed to in writing,
    16   * software distributed under the License is distributed on an
    17   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    18   * KIND, either express or implied.  See the License for the
    19   * specific language governing permissions and limitations
    20   * under the License.
    21   */
    22
    23
    24  import java.io.IOException;
    25
    26  import org.apache.turbine.util.RunData;
    27  import org.apache.turbine.util.TurbineException;
    28
    29  /**
    30   * Valve that can be used as the basis of Valve implementations.
    31   *
    32   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
    33   * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    34   * @version $Id: AbstractValve.java 757213 2009-03-22 16:43:31Z tv $
    35   */
    36  public abstract class AbstractValve
    37      implements Valve
    38  {
    39      /**
    40       * Initialize this valve for use in a pipeline.
    41       *
    42       * @throws Exception
    43       */
    44      public void initialize()
    45          throws Exception
    46      {
    47          // empty
    48      }
    49
    50      /**
    51       * @see org.apache.turbine.Valve#invoke(PipelineData, ValveContext)
    52       */
    53      public abstract void invoke(PipelineData data, ValveContext context)
    54          throws IOException, TurbineException;
    55
    56
    57      /**
    58       * utility for getting RunData out of the pielineData object.
    59       * @param pipelineData
    60       * @return
    61       */
    62      public final RunData getRunData(PipelineData pipelineData)
    63      {
    64          if(!(pipelineData instanceof RunData)){
    65              throw new RuntimeException("Can't cast pipelineData to rundata");
    66          }
    67          return (RunData)pipelineData;
    68      }
    69
    70  }