[ 
https://issues.apache.org/jira/browse/VFS-525?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Otto Fowler updated VFS-525:
----------------------------
    Comment: was deleted

(was: OK,

This is working as designed.  It only *seems* broken when you do not consider 
the DefaultFileMonitor:

 
{code:java}
 DefaultFileMonitor fm = new DefaultFileMonitor(new FileListener() {

                @Override
                public void fileDeleted(FileChangeEvent event) throws Exception 
{
                    System.out.println(event.getFile().getName().getPath()+" 
Deleted.");
                }

                @Override
                public void fileCreated(FileChangeEvent event) throws Exception 
{
                    System.out.println(event.getFile().getName().getPath()+" 
Created.");
                }

                @Override
                public void fileChanged(FileChangeEvent event) throws Exception 
{
                    System.out.println(event.getFile().getName().getPath()+" 
Changed.");
                }
            });
            fm.setRecursive(true);
            fm.addFile(listendir);
            fm.start();
{code}
In other words, if you want to monitor for changes external to VFS you need to 
use this.

 

BUT:  the FTP provider, because it is written to speed up access is implemented 
in such a way that the monitor doesn't work.

 

 )

> FtpFileObject.exists() output not impacted by refresh() after file deletion
> ---------------------------------------------------------------------------
>
>                 Key: VFS-525
>                 URL: https://issues.apache.org/jira/browse/VFS-525
>             Project: Commons VFS
>          Issue Type: Bug
>    Affects Versions: 2.0
>         Environment: Windows 7 [Version 6.1.7601]
> java version "1.6.0_31"
> Java(TM) SE Runtime Environment (build 1.6.0_31-b05)
> Java HotSpot(TM) Client VM (build 20.6-b01, mixed mode, sharing)
> commonc vfs 2.0
> commons net 3.3
>            Reporter: Volker Bergmann
>            Priority: Critical
>              Labels: FTP,, cache, exists
>
> Context: I store a file in an FTP directory and poll the FTP file (using 
> FtpFileObject.exists()) until it is imported by another system and deleted on 
> the FTP folder.
> Issue: On the first lookup, the file is present and FtpFileObject.exists() 
> returns true correctly. That's OK, but after the file has been deleted, 
> FtpFileObject.exists() continues to return true, even when using 
> CacheStrategy.MANUAL and calling FtpFileObject.refresh().
> Observations: Upon refresh() there is a complex interaction between the file 
> and parent folder object as well as the code of AbstractFileObject and 
> FtpFileObject. The issue seems to stem from the fact that for the existence 
> check of a file, its parent file object is queried for its #children 
> attribute which caches the child entries. On the one hand, the child file 
> seems to clear the link to the parent folder, causing a detach() of the 
> parent, but since the parent folder already is in detached state, it does not 
> clear its #children attribute. 
> By the way: I consider it a poor inheritance design if a child class 
> attribute 
>     FtpFileObject: private Map<String, FTPFile> children
> shadows a parent class attribute
>     AbstractFileObject: private FileName[] children
> At least it makes debugging more cumbersome.
> Workaround: The issue stems from the fact that the parent FtpFileObject is 
> not cleared correctly because attached==false. Thus I use a call to the 
> parent's getType() method which causes an attach() and, finally, attached== 
> true and then call refresh() on the parent and the child:
> // This is a workaround for VFS 2.0's flaws in the 
> // handling of attached/detached state and caching:
> FileObject parent = file.getParent();
> parent.getType(); // assure that parent folder is attached
> parent.refresh(); // detach parent folder and clear child object cache 
>                         // (works only if attached before)
> // ...end of workaround
> file.refresh();
> System.out.println("File.exists(): {}", file.exists());



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