Continuously scan if a file exists in a folder

Question

I have a folder with alot of different data types (xls, doc, ....). If there is a new file with some specific file extension (.avi) && the first letter of the file name starts with "EN_", the file should be moved to another folder. This should be run continuously, means when some file got moved it starts immediately with scanning for the next file with the specific properties (.avi & EN_). With my current knowledge I just would use a endless while loop. Is there maybe any other solution? How would you solve it?

Thanks in advance.

With Java 7, yes; with Java 6, you have to resort to an infinite loop. — fge, Mar 29 '15 at 17:23
Consider [java.nio.file.WatchService](http://docs.oracle.com/javase/8/docs/api/java/nio/file/WatchService.html). — Jeffrey Bosboom, Mar 29 '15 at 17:30

score 1 · Answer 1 · edited May 23 '17 at 12:10

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You could try to use JNotify library, it should be more efficient than a while loop: http://jnotify.sourceforge.net/

I never used it, but I think this library makes use of OS specific features. For example, in Linux you have inotify, which allows you to listen for filesystem events.

P.S. As mentioned in another thread, you should you Java 7 new file API for this: How does Jnotify works

edited May 23 '17 at 12:10

Community

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answered Mar 29 '15 at 17:27

Konstantin Milyutin

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Thanks, im gonna test this lib. – Panther Mar 29 '15 at 17:52
Have you seen the "P.S." part? – Konstantin Milyutin Mar 29 '15 at 17:55

Tenzin · Answer 2 · 2015-03-29T17:27:03.693

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You could write a infinite loop that makes use of a try catch. Try to find the file, if it is not there it will execute the catch.

edited Mar 29 '15 at 17:27

answered Mar 29 '15 at 17:25

Tenzin

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bad idea. he should have a look here: http://java.dzone.com/news/how-watch-file-system-changes `...` but of course the Panther should have used Google `;)` – Benjamin M Mar 29 '15 at 17:26

score 0 · Answer 3 · answered Mar 29 '15 at 17:46

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With Java 8 you can create a WatchService.

It will allow you to watch for changes to a directory of a certain type.

answered Mar 29 '15 at 17:46

David S.

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Continuously scan if a file exists in a folder

3 Answers3