Class FileChangedReloadingStrategy

java.lang.Object
org.apache.commons.configuration.reloading.FileChangedReloadingStrategy
All Implemented Interfaces:
ReloadingStrategy
public class FileChangedReloadingStrategy extends Object implements ReloadingStrategy

A reloading strategy that will reload the configuration every time its underlying file is changed.

This reloading strategy does not actively monitor a configuration file, but is triggered by its associated configuration whenever properties are accessed. It then checks the configuration file's last modification date and causes a reload if this has changed.

To avoid permanent disc access on successive property lookups a refresh delay can be specified. This has the effect that the configuration file's last modification date is only checked once in this delay period. The default value for this refresh delay is 5 seconds.

This strategy only works with FileConfiguration instances.

Since:
1.1
Version:
$Id: FileChangedReloadingStrategy.java 1210646 2011-12-05 21:25:01Z oheger $
Author:
Emmanuel Bourg

  • Field Details

    • configuration

      protected FileConfiguration configuration
      Stores a reference to the configuration to be monitored.

    • lastModified

      protected long lastModified
      The last time the configuration file was modified.

    • lastChecked

      protected long lastChecked
      The last time the file was checked for changes.

    • refreshDelay

      protected long refreshDelay
      The minimum delay in milliseconds between checks.

  • Constructor Details

  • Method Details

    • setConfiguration

      public void setConfiguration(FileConfiguration configuration)
      Description copied from interface: ReloadingStrategy
      Set the configuration managed by this strategy.
      Specified by:
      setConfiguration in interface ReloadingStrategy
      Parameters:
      configuration - the configuration to monitor

    • init

      public void init()
      Description copied from interface: ReloadingStrategy
      Initialize the strategy.
      Specified by:
      init in interface ReloadingStrategy

    • reloadingRequired

      public boolean reloadingRequired()
      Description copied from interface: ReloadingStrategy
      Tell if the evaluation of the strategy requires to reload the configuration.
      Specified by:
      reloadingRequired in interface ReloadingStrategy
      Returns:
      a flag whether a reload should be performed

    • reloadingPerformed

      public void reloadingPerformed()
      Description copied from interface: ReloadingStrategy
      Notify the strategy that the file has been reloaded.
      Specified by:
      reloadingPerformed in interface ReloadingStrategy

    • getRefreshDelay

      public long getRefreshDelay()
      Return the minimal time in milliseconds between two reloadings.
      Returns:
      the refresh delay (in milliseconds)

    • setRefreshDelay

      public void setRefreshDelay(long refreshDelay)
      Set the minimal time between two reloadings.
      Parameters:
      refreshDelay - refresh delay in milliseconds

    • updateLastModified

      protected void updateLastModified()
      Update the last modified time.

    • hasChanged

      protected boolean hasChanged()
      Check if the configuration has changed since the last time it was loaded.
      Returns:
      a flag whether the configuration has changed

    • getFile

      protected File getFile()
      Returns the file that is monitored by this strategy. Note that the return value can be null under some circumstances.
      Returns:
      the monitored file