import groovy.transform.CompileStatic


@CompileStatic
enum MyEnum {
  ONE(1),
  TWO(2)
  
  final int id
  
  MyEnum(int id) {
    this.id = id
  }
}
    
@CompileStatic
class Test{

    
    // static utility function, had to add the static modifier
   static int initSomething(int enumId) {
      
      switch (enumId) {
        case MyEnum.ONE.id:
            return 1
    
        case MyEnum.TWO.id:
           return 2
      }
      
      return 1 //cant return null because not Integer...
    }
}

println Test.initSomething(1)