How to explore a PSITree in intellij API?

Question

I want to build an Intellij plugin that identifies scala classes with certain annotations.

ex:

@RunWith(classOf[SimpleTestRunner])

When I build the PSITree using the PSIViewer pluging for the last code segment I get this Tree

ScalaFile:Dummy.scala(0,36)
  PsiErrorElement:Wrong top statement declaration(0,0)
    <empty list>
  PsiElement(@)('@')(0,1)
  MethodCall(1,35)
    ReferenceExpression: RunWith(1,8)
      PsiElement(identifier)('RunWith')(1,8)
    ArgumentList(8,35)
      PsiElement(()('(')(8,9)
      GenericCall(9,34)
        ReferenceExpression: classOf(9,16)
          PsiElement(identifier)('classOf')(9,16)
        TypeArgumentsList(16,34)
          PsiElement([)('[')(16,17)
          SimpleType: SimpleTestRunner(17,33)
            CodeReferenceElement: SimpleTestRunner(17,33)
              PsiElement(identifier)('SimpleTestRunner')(17,33)
          PsiElement(])(']')(33,34)
      PsiElement())(')')(34,35)

Now, I'm trying to access children with navigation element "ReferenceExpression,ArgumentList,GenericCall", I know how to visit tree recursively, but I don't know what to look for.

So can someone tell me what are the interfaces that represents these elements or is there sort of a utiltiy class that could help me to do so?

Answer 1

I assume you have the source code of the Scala plugin?

The interfaces (or Scala traits actually) are defined in the org.jetbrains.plugins.scale.lang.psi.api package. There you can find ./expr/ScGenericCall.scala for example. Every element in your tree has a corresponding Sc<NAME>.scala file where it is defined.