Is there a way to trigger data fetcher if a specific field is requested irrespective of it's parent

[arunnaparna]

I would like to trigger a data fetcher when the request is for a specific attribute/field. This field can be part of multiple Types.

e.g.,

interface SourceInformation{
  fromA : String
  fromB: String
}

type One implements SourceInformation {
   name: String
   fromA : String
   fromB: String
}
type Two  implements SourceInformation{
   name: String
   fromA : String
   fromB: String
}

type Request {
    one: One
    two: Two
}

With this structure, if the request is for fromA, can we trigger a data fetcher? This field can be part of either One or Two types.
I have gone through the section Nested Data fetchers in https://netflix.github.io/dgs/advanced/context-passing/
Can the framework handle such usecase? or should it be handled explicitly using:
datafetchingenvironment.getSelectionSet().contains("fromA")

[paulbakker]

I might be misunderstanding the question. But here's an attempt at an answer. You can just define the datafetcher for fromA on either the interface type or the concrete types.

@DgsData(parentType="SourceInformation")
public String fromA() {

}

This would define a single datafetcher that works for both One and Two. Alternatively you can create the datafetcher for the implementing type explicitly:

@DgsData(parentType="One")
public String fromA() {

}

@DgsData(parentType="Two")
public String fromA() {

}