CAMEL-11656 - add preSort option

[onderson]

even though i believe this issue is not related to sorting file list beforehand, i am just opening the PR to discuss further and revise...
@davsclaus could you review?

[oscerd]

In my opinion it can be good to have this, but we need to avoid the options number explosion in this component. Lets wait for @davsclaus

[davsclaus]

As much as I love the java 8 stream api, then this would create a 2nd list for sorting, where as Collections.sort would work on existing ArrayList and not use a 2nd list. We had some examples where users had 100.000+ files in a dir that would eat up memory (more in particular with the ftp, where there is a FTP remote file object instance)

I wonder if we can sort using non java 8 streaming

[onderson]

yes sure.updated.

[davsclaus]

Maybe we can improved the documentation a bit, something like:

When pre-sort is enabled then the consumer will sort the file and directory names during polling, that was retrieved from the file system. You may want to do this in case you need to operate on the files in a sorted order. The pre-sort is executed before the consumer starts to filter, and accept files to process by Camel. This option is default disabled.

[oscerd]

@onders86 is there a specific reason to backport to 2.20.x? This is a new option, so usually we avoid new options in minor releases

[onderson]

@oscerd No there is not. I thought we would need to backport because this was a wish since 2.19.0. I dont mind reverting. Let me know.

[onderson]

@oscerd , reverted.