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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  }