org.apache.commons.io

Class FileCleaner

public class FileCleaner extends Object

Deprecated: Use FileCleaningTracker

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 FileCleaner, typically in javax.servlet.ServletContextListener#contextDestroyed or similar.

Version: $Id: FileCleaner.java 553012 2007-07-03 23:01:07Z ggregory $

Author: Noel Bergman Martin Cooper

Field Summary
static FileCleaningTrackertheInstance
The instance to use for the deprecated, static methods.
Method Summary
static voidexitWhenFinished()
Call this method to cause the file cleaner thread to terminate when there are no more objects being tracked for deletion.
static FileCleaningTrackergetInstance()
Returns the singleton instance, which is used by the deprecated, static methods.
static intgetTrackCount()
Retrieve the number of files currently being tracked, and therefore awaiting deletion.
static voidtrack(File file, Object marker)
Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected.
static voidtrack(File file, Object marker, FileDeleteStrategy deleteStrategy)
Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected.
static voidtrack(String path, Object marker)
Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected.
static voidtrack(String path, Object marker, FileDeleteStrategy deleteStrategy)
Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected.

Field Detail

theInstance

static final FileCleaningTracker theInstance
The instance to use for the deprecated, static methods.

Method Detail

exitWhenFinished

public static void exitWhenFinished()

Deprecated: Use exitWhenFinished.

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 javax.servlet.ServletContextListener#contextDestroyed. One called, no new objects can be tracked by the file cleaner.

getInstance

public static FileCleaningTracker getInstance()
Returns the singleton instance, which is used by the deprecated, static methods. This is mainly useful for code, which wants to support the new FileCleaningTracker class while maintain compatibility with the deprecated FileCleaner.

Returns: the singleton instance

getTrackCount

public static int getTrackCount()

Deprecated: Use getTrackCount.

Retrieve the number of files currently being tracked, and therefore awaiting deletion.

Returns: the number of files being tracked

track

public static void track(File file, Object marker)

Deprecated: Use FileCleaningTracker.

Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected. The normal deletion strategy will be used.

Parameters: file the file to be tracked, not null marker the marker object used to track the file, not null

Throws: NullPointerException if the file is null

track

public static void track(File file, Object marker, FileDeleteStrategy deleteStrategy)

Deprecated: Use FileCleaningTracker.

Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected. The speified deletion strategy is used.

Parameters: file the file to be tracked, not null marker the marker object used to track the file, not null deleteStrategy the strategy to delete the file, null means normal

Throws: NullPointerException if the file is null

track

public static void track(String path, Object marker)

Deprecated: Use FileCleaningTracker.

Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected. The normal deletion strategy will be used.

Parameters: path the full path to the file to be tracked, not null marker the marker object used to track the file, not null

Throws: NullPointerException if the path is null

track

public static void track(String path, Object marker, FileDeleteStrategy deleteStrategy)

Deprecated: Use FileCleaningTracker.

Track the specified file, using the provided marker, deleting the file when the marker instance is garbage collected. The speified deletion strategy is used.

Parameters: path the full path to the file to be tracked, not null marker the marker object used to track the file, not null deleteStrategy the strategy to delete the file, null means normal

Throws: NullPointerException if the path is null

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