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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  
18  package org.apache.commons.configuration.reloading;
19  
20  import org.apache.commons.configuration.FileConfiguration;
21  import org.apache.commons.logging.Log;
22  import org.apache.commons.logging.LogFactory;
23  
24  /**
25   * A strategy to reload configuration based on management requests. Designed for
26   * JMX management.
27   *
28   * @author Nicolas De loof
29   * @version $Id: ManagedReloadingStrategy.java 1210646 2011-12-05 21:25:01Z oheger $
30   */
31  public class ManagedReloadingStrategy implements ReloadingStrategy,
32          ManagedReloadingStrategyMBean
33  {
34      /** The logger. */
35      private Log log = LogFactory.getLog(ManagedReloadingStrategy.class);
36  
37      /** Stores a reference to the associated configuration. */
38      private FileConfiguration configuration;
39  
40      /** A flag whether a reload is required. */
41      private boolean reloadingRequired;
42  
43      /**
44       * @see org.apache.commons.configuration.reloading.ReloadingStrategy#init()
45       */
46      public void init()
47      {
48      }
49  
50      /**
51       * @see org.apache.commons.configuration.reloading.ReloadingStrategy#reloadingPerformed()
52       */
53      public void reloadingPerformed()
54      {
55          reloadingRequired = false;
56      }
57  
58      /**
59       * Checks whether reloading is required. This implementation checks whether
60       * the {@code refresh()} method has been invoked.
61       *
62       * @return a flag whether reloading is required
63       * @see org.apache.commons.configuration.reloading.ReloadingStrategy#reloadingRequired()
64       */
65      public boolean reloadingRequired()
66      {
67          return reloadingRequired;
68      }
69  
70      /**
71       * Sets the associated configuration.
72       *
73       * @param configuration the associated configuration
74       */
75      public void setConfiguration(FileConfiguration configuration)
76      {
77          this.configuration = configuration;
78      }
79  
80      /**
81       * Tells this strategy that the monitored configuration file should be
82       * refreshed. This method will typically be called from outside (through an
83       * exposed MBean) on behalf of an administrator.
84       *
85       * @see org.apache.commons.configuration.reloading.ManagedReloadingStrategyMBean#refresh()
86       */
87      public void refresh()
88      {
89          log.info("Reloading configuration.");
90          this.reloadingRequired = true;
91          // force reloading
92          configuration.isEmpty();
93      }
94  }