Coverage Report - org.apache.commons.configuration.reloading.FileChangedReloadingStrategy
 
Classes in this File Line Coverage Branch Coverage Complexity
FileChangedReloadingStrategy
97%
31/32
100%
7/7
1,9
 
 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: 439648 $, $Date: 2006-09-02 22:42:10 +0200 (Sa, 02 Sep 2006) $
 42  
  * @since 1.1
 43  
  */
 44  22
 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  11
     protected long refreshDelay = DEFAULT_REFRESH_DELAY;
 63  
 
 64  
     public void setConfiguration(FileConfiguration configuration)
 65  
     {
 66  10
         this.configuration = configuration;
 67  10
     }
 68  
 
 69  
     public void init()
 70  
     {
 71  13
         updateLastModified();
 72  13
     }
 73  
 
 74  
     public boolean reloadingRequired()
 75  
     {
 76  452
         boolean reloading = false;
 77  
 
 78  452
         long now = System.currentTimeMillis();
 79  
 
 80  452
         if (now > lastChecked + refreshDelay)
 81  
         {
 82  10
             lastChecked = now;
 83  10
             if (hasChanged())
 84  
             {
 85  3
                 reloading = true;
 86  
             }
 87  
         }
 88  
 
 89  452
         return reloading;
 90  
     }
 91  
 
 92  
     public void reloadingPerformed()
 93  
     {
 94  3
         updateLastModified();
 95  3
     }
 96  
 
 97  
     /**
 98  
      * Return the minimal time in milliseconds between two reloadings.
 99  
      *
 100  
      * @return the refresh delay (in milliseconds)
 101  
      */
 102  
     public long getRefreshDelay()
 103  
     {
 104  2
         return refreshDelay;
 105  
     }
 106  
 
 107  
     /**
 108  
      * Set the minimal time between two reloadings.
 109  
      *
 110  
      * @param refreshDelay refresh delay in milliseconds
 111  
      */
 112  
     public void setRefreshDelay(long refreshDelay)
 113  
     {
 114  7
         this.refreshDelay = refreshDelay;
 115  7
     }
 116  
 
 117  
     /**
 118  
      * Update the last modified time.
 119  
      */
 120  
     protected void updateLastModified()
 121  
     {
 122  16
         File file = getFile();
 123  16
         if (file != null)
 124  
         {
 125  16
             lastModified = file.lastModified();
 126  
         }
 127  16
     }
 128  
 
 129  
     /**
 130  
      * Check if the configuration has changed since the last time it was loaded.
 131  
      *
 132  
      * @return a flag whether the configuration has changed
 133  
      */
 134  
     protected boolean hasChanged()
 135  
     {
 136  10
         File file = getFile();
 137  10
         if (file == null || !file.exists())
 138  
         {
 139  1
             return false;
 140  
         }
 141  
 
 142  9
         return file.lastModified() > lastModified;
 143  
     }
 144  
 
 145  
     /**
 146  
      * Returns the file that is monitored by this strategy. Note that the return
 147  
      * value can be <b>null </b> under some circumstances.
 148  
      *
 149  
      * @return the monitored file
 150  
      */
 151  
     protected File getFile()
 152  
     {
 153  28
         return (configuration.getURL() != null) ? fileFromURL(configuration
 154  
                 .getURL()) : configuration.getFile();
 155  
     }
 156  
 
 157  
     /**
 158  
      * Helper method for transforming a URL into a file object. This method
 159  
      * handles file: and jar: URLs.
 160  
      *
 161  
      * @param url the URL to be converted
 162  
      * @return the resulting file or <b>null </b>
 163  
      */
 164  
     private File fileFromURL(URL url)
 165  
     {
 166  26
         if (JAR_PROTOCOL.equals(url.getProtocol()))
 167  
         {
 168  2
             String path = url.getPath();
 169  
             try
 170  
             {
 171  2
                 return ConfigurationUtils.fileFromURL(new URL(path.substring(0,
 172  
                         path.indexOf('!'))));
 173  
             }
 174  
             catch (MalformedURLException mex)
 175  
             {
 176  0
                 return null;
 177  
             }
 178  
         }
 179  
         else
 180  
         {
 181  24
             return ConfigurationUtils.fileFromURL(url);
 182  
         }
 183  
     }
 184  
 }