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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.fileupload.servlet;
18  
19  import javax.servlet.ServletContext;
20  import javax.servlet.ServletContextListener;
21  import javax.servlet.ServletContextEvent;
22  
23  import org.apache.commons.io.FileCleaningTracker;
24  
25  /**
26   * A servlet context listener, which ensures that the
27   * {@link FileCleaningTracker}'s reaper thread is terminated,
28   * when the web application is destroyed.
29   */
30  public class FileCleanerCleanup implements ServletContextListener {
31  
32      /**
33       * Attribute name, which is used for storing an instance of
34       * {@link FileCleaningTracker} in the web application.
35       */
36      public static final String FILE_CLEANING_TRACKER_ATTRIBUTE
37          = FileCleanerCleanup.class.getName() + ".FileCleaningTracker";
38  
39      /**
40       * Returns the instance of {@link FileCleaningTracker}, which is
41       * associated with the given {@link ServletContext}.
42       *
43       * @param pServletContext The servlet context to query
44       * @return The contexts tracker
45       */
46      public static FileCleaningTracker
47              getFileCleaningTracker(ServletContext pServletContext) {
48          return (FileCleaningTracker)
49              pServletContext.getAttribute(FILE_CLEANING_TRACKER_ATTRIBUTE);
50      }
51  
52      /**
53       * Sets the instance of {@link FileCleaningTracker}, which is
54       * associated with the given {@link ServletContext}.
55       *
56       * @param pServletContext The servlet context to modify
57       * @param pTracker The tracker to set
58       */
59      public static void setFileCleaningTracker(ServletContext pServletContext,
60              FileCleaningTracker pTracker) {
61          pServletContext.setAttribute(FILE_CLEANING_TRACKER_ATTRIBUTE, pTracker);
62      }
63  
64      /**
65       * Called when the web application is initialized. Does
66       * nothing.
67       *
68       * @param sce The servlet context, used for calling
69       *   {@link #setFileCleaningTracker(ServletContext, FileCleaningTracker)}.
70       */
71      @Override
72      public void contextInitialized(ServletContextEvent sce) {
73          setFileCleaningTracker(sce.getServletContext(),
74                  new FileCleaningTracker());
75      }
76  
77      /**
78       * Called when the web application is being destroyed.
79       * Calls {@link FileCleaningTracker#exitWhenFinished()}.
80       *
81       * @param sce The servlet context, used for calling
82       *     {@link #getFileCleaningTracker(ServletContext)}.
83       */
84      @Override
85      public void contextDestroyed(ServletContextEvent sce) {
86          getFileCleaningTracker(sce.getServletContext()).exitWhenFinished();
87      }
88  
89  }