[jira] [Commented] (VFS-508) Change FileSystemException to inherit from a RuntimeException, and not IOException (patch attached)

["Gary Gregory (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/VFS-508?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13848633#comment-13848633 ] 

Gary Gregory commented on VFS-508:
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Hi All:

I am more concerned about using the proper abstraction than ease of use. For this I'll simply reference Joshua Block's _Effective Java_ and Chapter 9:
- Item 57: "Use exceptions only for exceptional conditions" 
- Item 58: "Use checked exceptions for recoverable conditions and runtime exceptions for programming errors"
- and all the other items in the chapter.

I think we should frame the discussion of changing VFS exceptions in these best practices or confirm that we have it right.

This would also break binary compatibility with 2.0, and therefore would have to be in 3.0. I see the next (overdue!) release as 2.1. There are so many changes ready that 3.0 might be a better version number, but that's a different story.

Gary

> Change FileSystemException to inherit from a RuntimeException, and not IOException (patch attached)
> ---------------------------------------------------------------------------------------------------
>
>                 Key: VFS-508
>                 URL: https://issues.apache.org/jira/browse/VFS-508
>             Project: Commons VFS
>          Issue Type: Improvement
>            Reporter: Shant Stepanian
>         Attachments: changeFileSystemToRuntime.patch
>
>
> I'd like to see if we can FileSystemException to inherit from a RuntimeException, and not IOException
> I searched the JIRA and didn't see any old tickets referring to this, so I'll bring it up here
> _The reason_
> The reason would go back to the whole "Runtime vs. Checked" exception debate, and I do prefer the RuntimeException argument that with those, you have the choice on whether to declare the try/catch block upon usage, whereas Checked exceptions force that on you
> In particular, I bring this up because I feel it hurts the usability of the API to have all operations as a checked exception. I recently looked to convert my code from using the regular Java JDK file api to the VFS api, and I found that in a number of places, I now have to add a try/catch block to handle a checked exception where I previously didn't have to (e.g. File.listFiles() vs. FileObject.getChildren(), new File("myFile") vs. VFS.getManager().resolveFile("myFile"))
> Having one less impediment to migrate would make it easier to adopt for more people. As a frame of reference, Hibernate did make a change like this to convert HibernateException from checked to runtime, and it was fine for them
> _Patch and Impact of Change_
> I've attached a patch of the change - you can see it is very small, and the code still compiles. I ran a test locally and it failed on some of the external-resource-related bits; I can follow up on this, but would like to first get your approval on this ticket before proceeding w/ any more work
> In terms of client changes - this would only impact clients that happened to explicitly expect an IOException in their catch block, and not directly the FileSystemException. (this affected one piece of code within VFS itself, but could affect clients).
> But I believe that this still would be a beneficial change, as it would make all clients' code cleaner and make it easier to adopt



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