Checking if file is completely written [duplicate]

Question

Currently I'm working on the project that does processing files from source directory in one of it's routines. There's a Java process that's looking for specified directory and tries to read and process files if they exist. Files are quit large and updates by other thirdparty process. The question is how can I check if the file is completely written? I'm trying to use file.length() but looks like even if writing process hasn't been completed it returns actual size. I have a feeling that solution should be platform dependent. Any help would be appreciated.

UPDATE: This question is not really different from the duplicate but it has an answer with working code snippet that is highly rated.

Answer 1

I got the solution working:

private boolean isCompletelyWritten(File file) {     RandomAccessFile stream = null;     try {         stream = new RandomAccessFile(file, "rw");         return true;     } catch (Exception e) {         log.info("Skipping file " + file.getName() + " for this iteration due it's not completely written");     } finally {         if (stream != null) {             try {                 stream.close();             } catch (IOException e) {                 log.error("Exception during closing file " + file.getName());             }         }     }     return false; } 

Thanks to @cklab and @Will and all others who suggested to look in "exclusive lock" way. I just posted code here to make other interested in people use it. I believe the solution with renaming suggested by @tigran also works but pure Java solution is preferable for me.

P.S. Initially I used FileOutputStream instead of RandomAccessFile but it locks file being written.