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FileCleaner.javaAPI DocAndroid 1.5 API7082Wed May 06 22:42:46 BST 2009org.apache.commons.io

FileCleaner

public class FileCleaner extends Object
Keeps track of files awaiting deletion, and deletes them when an associated marker object is reclaimed by the garbage collector.

This utility creates a background thread to handle file deletion. Each file to be deleted is registered with a handler object. When the handler object is garbage collected, the file is deleted.

In an environment with multiple class loaders (a servlet container, for example), you should consider stopping the background thread if it is no longer needed. This is done by invoking the method {@link #exitWhenFinished}, typically in {@link javax.servlet.ServletContextListener#contextDestroyed} or similar.

author
Noel Bergman
author
Martin Cooper
version
$Id: FileCleaner.java 553012 2007-07-03 23:01:07Z ggregory $
deprecated
Use {@link FileCleaningTracker}

Fields Summary
static final FileCleaningTracker
theInstance
The instance to use for the deprecated, static methods.
Constructors Summary
Methods Summary
public static synchronized voidexitWhenFinished()
Call this method to cause the file cleaner thread to terminate when there are no more objects being tracked for deletion.

In a simple environment, you don't need this method as the file cleaner thread will simply exit when the JVM exits. In a more complex environment, with multiple class loaders (such as an application server), you should be aware that the file cleaner thread will continue running even if the class loader it was started from terminates. This can consitute a memory leak.

For example, suppose that you have developed a web application, which contains the commons-io jar file in your WEB-INF/lib directory. In other words, the FileCleaner class is loaded through the class loader of your web application. If the web application is terminated, but the servlet container is still running, then the file cleaner thread will still exist, posing a memory leak.

This method allows the thread to be terminated. Simply call this method in the resource cleanup code, such as {@link javax.servlet.ServletContextListener#contextDestroyed}. One called, no new objects can be tracked by the file cleaner.

deprecated
Use {@link FileCleaningTracker#exitWhenFinished()}.

        theInstance.exitWhenFinished();
    
public static org.apache.commons.io.FileCleaningTrackergetInstance()
Returns the singleton instance, which is used by the deprecated, static methods. This is mainly useful for code, which wants to support the new {@link FileCleaningTracker} class while maintain compatibility with the deprecated {@link FileCleaner}.

return
the singleton instance

        return theInstance;
    
public static intgetTrackCount()
Retrieve the number of files currently being tracked, and therefore awaiting deletion.

return
the number of files being tracked
deprecated
Use {@link FileCleaningTracker#getTrackCount()}.

        return theInstance.getTrackCount();
    
public static voidtrack(java.io.File file, java.lang.Object marker)
Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected. The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.

param
file the file to be tracked, not null
param
marker the marker object used to track the file, not null
throws
NullPointerException if the file is null
deprecated
Use {@link FileCleaningTracker#track(File, Object)}.


    //-----------------------------------------------------------------------
                                                                       
           
        theInstance.track(file, marker);
    
public static voidtrack(java.io.File file, java.lang.Object marker, org.apache.commons.io.FileDeleteStrategy deleteStrategy)
Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected. The speified deletion strategy is used.

param
file the file to be tracked, not null
param
marker the marker object used to track the file, not null
param
deleteStrategy the strategy to delete the file, null means normal
throws
NullPointerException if the file is null
deprecated
Use {@link FileCleaningTracker#track(File, Object, FileDeleteStrategy)}.

        theInstance.track(file, marker, deleteStrategy);
    
public static voidtrack(java.lang.String path, java.lang.Object marker)
Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected. The {@link FileDeleteStrategy#NORMAL normal} deletion strategy will be used.

param
path the full path to the file to be tracked, not null
param
marker the marker object used to track the file, not null
throws
NullPointerException if the path is null
deprecated
Use {@link FileCleaningTracker#track(String, Object)}.

        theInstance.track(path, marker);
    
public static voidtrack(java.lang.String path, java.lang.Object marker, org.apache.commons.io.FileDeleteStrategy deleteStrategy)
Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected. The speified deletion strategy is used.

param
path the full path to the file to be tracked, not null
param
marker the marker object used to track the file, not null
param
deleteStrategy the strategy to delete the file, null means normal
throws
NullPointerException if the path is null
deprecated
Use {@link FileCleaningTracker#track(String, Object, FileDeleteStrategy)}.

        theInstance.track(path, marker, deleteStrategy);