Avoid detecting incomplete files when watching a directory for changes in java

Question

I am watching a directory for incoming files (using FileAlterationObserver from apache commons).

class Example implements FileAlterationListener {
    public         


        

Answer 1

A generic solution to this problem seems impossible from the "consumer" end. The "producer" may temporarily close the file and then resume appending to it. Or the "producer" may crash, leaving an incomplete file in the file system.

A reasonable pattern is to have the "producer" write to a temp file that's not monitored by the "consumer". When it's done writing, rename the file to something that's actually monitored by the "consumer", at which point the "consumer" will pick up the complete file.