public class FileCleaningTracker extends Object
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
exitWhenFinished, typically in
javax.servlet.ServletContextListener.contextDestroyed(javax.servlet.ServletContextEvent) or similar.
| 构造器和说明 |
|---|
FileCleaningTracker() |
| 限定符和类型 | 方法和说明 |
|---|---|
void |
exitWhenFinished()
Call this method to cause the file cleaner thread to terminate when
there are no more objects being tracked for deletion.
|
List<String> |
getDeleteFailures()
Return the file paths that failed to delete.
|
int |
getTrackCount()
Retrieve the number of files currently being tracked, and therefore
awaiting deletion.
|
void |
track(File file,
Object marker)
Track the specified file, using the provided marker, deleting the file
when the marker instance is garbage collected.
|
void |
track(File file,
Object marker,
FileDeleteStrategy deleteStrategy)
Track the specified file, using the provided marker, deleting the file
when the marker instance is garbage collected.
|
void |
track(String path,
Object marker)
Track the specified file, using the provided marker, deleting the file
when the marker instance is garbage collected.
|
void |
track(String path,
Object marker,
FileDeleteStrategy deleteStrategy)
Track the specified file, using the provided marker, deleting the file
when the marker instance is garbage collected.
|
public void track(File file, Object marker)
normal deletion strategy will be used.file - the file to be tracked, not nullmarker - the marker object used to track the file, not nullNullPointerException - if the file is nullpublic void track(File file, Object marker, FileDeleteStrategy deleteStrategy)
file - the file to be tracked, not nullmarker - the marker object used to track the file, not nulldeleteStrategy - the strategy to delete the file, null means normalNullPointerException - if the file is nullpublic void track(String path, Object marker)
normal deletion strategy will be used.path - the full path to the file to be tracked, not nullmarker - the marker object used to track the file, not nullNullPointerException - if the path is nullpublic void track(String path, Object marker, FileDeleteStrategy deleteStrategy)
path - the full path to the file to be tracked, not nullmarker - the marker object used to track the file, not nulldeleteStrategy - the strategy to delete the file, null means normalNullPointerException - if the path is nullpublic int getTrackCount()
public List<String> getDeleteFailures()
public void exitWhenFinished()
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(javax.servlet.ServletContextEvent).
Once called, no new objects can be tracked by the file cleaner.