Coverage Report - org.apache.commons.configuration.reloading.FileChangedReloadingStrategy
 
Classes in this File Line Coverage Branch Coverage Complexity
FileChangedReloadingStrategy
94%
32/34
100%
8/8
2
 
 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 java.io.File;
 21  
 import java.net.MalformedURLException;
 22  
 import java.net.URL;
 23  
 
 24  
 import org.apache.commons.configuration.ConfigurationUtils;
 25  
 import org.apache.commons.configuration.FileConfiguration;
 26  
 
 27  
 /**
 28  
  * <p>A reloading strategy that will reload the configuration every time its
 29  
  * underlying file is changed.</p>
 30  
  * <p>This reloading strategy does not actively monitor a configuration file,
 31  
  * but is triggered by its associated configuration whenever properties are
 32  
  * accessed. It then checks the configuration file's last modification date
 33  
  * and causes a reload if this has changed.</p>
 34  
  * <p>To avoid permanent disc access on successive property lookups a refresh
 35  
  * delay can be specified. This has the effect that the configuration file's
 36  
  * last modification date is only checked once in this delay period. The default
 37  
  * value for this refresh delay is 5 seconds.</p>
 38  
  * <p>This strategy only works with FileConfiguration instances.</p>
 39  
  *
 40  
  * @author Emmanuel Bourg
 41  
  * @version $Revision: 606798 $, $Date: 2007-12-25 20:05:58 +0100 (Di, 25 Dez 2007) $
 42  
  * @since 1.1
 43  
  */
 44  37
 public class FileChangedReloadingStrategy implements ReloadingStrategy
 45  
 {
 46  
     /** Constant for the jar URL protocol.*/
 47  
     private static final String JAR_PROTOCOL = "jar";
 48  
 
 49  
     /** Constant for the default refresh delay.*/
 50  
     private static final int DEFAULT_REFRESH_DELAY = 5000;
 51  
 
 52  
     /** Stores a reference to the configuration to be monitored.*/
 53  
     protected FileConfiguration configuration;
 54  
 
 55  
     /** The last time the configuration file was modified. */
 56  
     protected long lastModified;
 57  
 
 58  
     /** The last time the file was checked for changes. */
 59  
     protected long lastChecked;
 60  
 
 61  
     /** The minimum delay in milliseconds between checks. */
 62  37
     protected long refreshDelay = DEFAULT_REFRESH_DELAY;
 63  
 
 64  
     /** A flag whether a reload is required.*/
 65  
     private boolean reloading;
 66  
 
 67  
     public void setConfiguration(FileConfiguration configuration)
 68  
     {
 69  39
         this.configuration = configuration;
 70  39
     }
 71  
 
 72  
     public void init()
 73  
     {
 74  42
         updateLastModified();
 75  42
     }
 76  
 
 77  
     public boolean reloadingRequired()
 78  
     {
 79  988
         if (!reloading)
 80  
         {
 81  987
             long now = System.currentTimeMillis();
 82  
 
 83  987
             if (now > lastChecked + refreshDelay)
 84  
             {
 85  15
                 lastChecked = now;
 86  15
                 if (hasChanged())
 87  
                 {
 88  3
                     reloading = true;
 89  
                 }
 90  
             }
 91  
         }
 92  
 
 93  988
         return reloading;
 94  
     }
 95  
 
 96  
     public void reloadingPerformed()
 97  
     {
 98  1936
         updateLastModified();
 99  1936
     }
 100  
 
 101  
     /**
 102  
      * Return the minimal time in milliseconds between two reloadings.
 103  
      *
 104  
      * @return the refresh delay (in milliseconds)
 105  
      */
 106  
     public long getRefreshDelay()
 107  
     {
 108  2
         return refreshDelay;
 109  
     }
 110  
 
 111  
     /**
 112  
      * Set the minimal time between two reloadings.
 113  
      *
 114  
      * @param refreshDelay refresh delay in milliseconds
 115  
      */
 116  
     public void setRefreshDelay(long refreshDelay)
 117  
     {
 118  15
         this.refreshDelay = refreshDelay;
 119  15
     }
 120  
 
 121  
     /**
 122  
      * Update the last modified time.
 123  
      */
 124  
     protected void updateLastModified()
 125  
     {
 126  1978
         File file = getFile();
 127  1978
         if (file != null)
 128  
         {
 129  1976
             lastModified = file.lastModified();
 130  
         }
 131  1978
         reloading = false;
 132  1978
     }
 133  
 
 134  
     /**
 135  
      * Check if the configuration has changed since the last time it was loaded.
 136  
      *
 137  
      * @return a flag whether the configuration has changed
 138  
      */
 139  
     protected boolean hasChanged()
 140  
     {
 141  14
         File file = getFile();
 142  14
         if (file == null || !file.exists())
 143  
         {
 144  1
             return false;
 145  
         }
 146  
 
 147  13
         return file.lastModified() > lastModified;
 148  
     }
 149  
 
 150  
     /**
 151  
      * Returns the file that is monitored by this strategy. Note that the return
 152  
      * value can be <b>null </b> under some circumstances.
 153  
      *
 154  
      * @return the monitored file
 155  
      */
 156  
     protected File getFile()
 157  
     {
 158  1995
         return (configuration.getURL() != null) ? fileFromURL(configuration
 159  
                 .getURL()) : configuration.getFile();
 160  
     }
 161  
 
 162  
     /**
 163  
      * Helper method for transforming a URL into a file object. This method
 164  
      * handles file: and jar: URLs.
 165  
      *
 166  
      * @param url the URL to be converted
 167  
      * @return the resulting file or <b>null </b>
 168  
      */
 169  
     private File fileFromURL(URL url)
 170  
     {
 171  1991
         if (JAR_PROTOCOL.equals(url.getProtocol()))
 172  
         {
 173  2
             String path = url.getPath();
 174  
             try
 175  
             {
 176  2
                 return ConfigurationUtils.fileFromURL(new URL(path.substring(0,
 177  
                         path.indexOf('!'))));
 178  
             }
 179  0
             catch (MalformedURLException mex)
 180  
             {
 181  0
                 return null;
 182  
             }
 183  
         }
 184  
         else
 185  
         {
 186  1989
             return ConfigurationUtils.fileFromURL(url);
 187  
         }
 188  
     }
 189  
 }