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1   package org.apache.turbine.modules;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import org.apache.turbine.Turbine;
23  import org.apache.turbine.pipeline.PipelineData;
24  
25  /**
26   * The purpose of this class is to allow one to load and execute Page
27   * modules.
28   *
29   * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
30   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
31   * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
32   * @version $Id: PageLoader.java 1773378 2016-12-09 13:19:59Z tv $
33   */
34  public class PageLoader
35      extends GenericLoader<Page>
36      implements Loader<Page>
37  {
38      /** The single instance of this class. */
39      private static PageLoader instance = new PageLoader();
40  
41      /**
42       * These ctor's are private to force clients to use getInstance()
43       * to access this class.
44       */
45      private PageLoader()
46      {
47          super();
48      }
49  
50      /**
51       * Attempts to load and execute the external page.
52       *
53       * @param pipelineData Turbine information.
54       * @param name Name of object that will execute the page.
55       * @throws Exception a generic exception.
56       */
57      @Override
58      public void exec(PipelineData pipelineData, String name)
59              throws Exception
60      {
61          // Execute page
62          getAssembler(name).build(pipelineData);
63      }
64  
65      /**
66       * Pulls out an instance of the object by name.  Name is just the
67       * single name of the object.
68       *
69       * @param name Name of object instance.
70       * @return A Screen with the specified name, or null.
71       * @throws Exception a generic exception.
72       */
73      @Override
74      public Page getAssembler(String name)
75          throws Exception
76      {
77          return getAssembler(Page.class, name);
78      }
79  
80      /**
81       * @see org.apache.turbine.modules.Loader#getCacheSize()
82       */
83      @Override
84      public int getCacheSize()
85      {
86          return PageLoader.getConfiguredCacheSize();
87      }
88  
89      /**
90       * The method through which this class is accessed.
91       *
92       * @return The single instance of this class.
93       */
94      public static PageLoader getInstance()
95      {
96          return instance;
97      }
98  
99      /**
100      * Helper method to get the configured cache size for this module
101      *
102      * @return the configure cache size
103      */
104     private static int getConfiguredCacheSize()
105     {
106         return Turbine.getConfiguration().getInt(Page.CACHE_SIZE_KEY,
107                 Page.CACHE_SIZE_DEFAULT);
108     }
109 }