Automatic data loader naming on classes annotated with nameless @DgsDataLoader

[jord1e]

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Pull Request type

• Bugfix
• Feature
• Refactoring (no functional changes, no api changes)
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Changes in this PR

This PR automatically names dataloaders, which is useful when using the DgsDataFetchingEnvironment#getDataLoader(Class) method.

It also implements automatic naming of field loaders, which is arguably less useful. If anyone objects to this we can error out on nameless field dataloaders.

Something to consider is that metric and tracing solutions may expose (field?)/class/package names of the dataloader. In the future we can add a DgsDataLoaderNamingFactory or something that gives library consumers the ability to modify the name programmatically (e.g. - only use the class name instead of the FQN) - this PR does not implement this.

Partially related to #861

Alternatives considered

Name the loaders manually (gets old quickly)

[srinivasankavitha]

Thanks for the PR. The changes look good to me, I need to test it out a bit before merging. Will do that this week.

[jord1e]

Please look at the automatic field naming the closest, I am seriously debating leaving it out (and throwing a exception on unnamed field dataloaders) because refactoring the field name breaks code (fields cannot be referenced as parameters in methods

[srinivasankavitha]

Regarding #904 (comment)

I agree, I think generating the names automatically for the field loaders feels like it may result in more confusion than help. Let's remove that and keep just the generation of class data loader names.

Otherwise looks good to me. Thanks for the PR!

[srinivasankavitha]

We can merge the PR after you get a chance to remove the generation of names for field data loaders. Thanks!

[jord1e]

Made the following changes:

• Fields annotated with nameless @DgsDataLoader now throw DgsUnnamedDataLoaderOnFieldException upon initialization
• Added javadoc/ktdoc
• DgsDataLoaderProvider refactoring to DRY up some code (did I just invent a new verb?)
• Replaced the prefix+_+fqnClassName with just Class.getSimpleName (this is unambiguous enough in my opinion)

[srinivasankavitha]

The changes look good to me. Will merge the Pr.