Alternatives to long polling?

Question

I have an application in JAVA which checks from the ftp server, whether a given file is updated or not. If the file is updated, I download the file again.
I am using long polling to check, whether the file has been modified. So I ping the FTP server every 5 seconds and check whether the modified date of the file is changed or not. If the date is modified, I re-download the file again.
Is there a better way to perform this operation, other than long polling?

Answer 1

In general, there are two approaches for checking for updates.

The first is the one that you mentioned, and that is polling for changes periodically.

The second solution, is to register a "hook" which will be invoked once a specific action is occurs. For example, when pushing to a git repository, you can create a hook to automatically start a build of the source code.

In your case, option two is not applicable. There isn't an obvious way to make the FTP server ping you once the files change.