Compiler plugin for detecting usage of Java classes

Thanks a lot Paul!

Did you use the REPL :power mode for the stuff above or something different?

With your help it works pretty well now. I have hit one problem though:
I'm interested in the type argument in stuff like

  trait Foo extends Bar[java.lang.Integer]
  val list = List[java.math.MathContext]()

I catch it in Template/ValDef, but I have the problem that I seem to have to work with Types (foo.tpe.typeArgs) instead of Symbols, which makes it difficult to work with and to print line numbers, positions, ...
Is there something I'm missing?

This is the corresponding snippet I wrote currently:

      def apply(unit: CompilationUnit) {
        for (tree <- unit.body) {
          tree match {
            case tree@Apply(fun, args)
              if fun.symbol.isJavaDefined && fun.symbol.isSourceMethod && fun.symbol.fullName != "java.lang.Object.<init>" =>
              printJava(fun, "Apply ")
            case tree@DefDef(mods, name, tparams, vparamss, tpt, rhs)
              if isJavaAndNotAccessor(mods, rhs.symbol) =>
              printJava(rhs, "DefDef")
            case tree@ValDef(mods, name, tpt, rhs) =>
              if (isJavaAndNotAccessor(mods, tpt.symbol))
                printJava(tpt, "ValDef")
              val typeArgs = tpt.tpe.typeArgs
              //FIMXE: Some classes like the numeric wrappers lack the "java.lang." part. Why?
              typeArgs.foreach(typeArg => /*if (typeArg.toLongString.startsWith("java"))*/ println("TpeArgs " + typeArg.toLongString))

            case tree@Template(parents, self, body) =>
              parents
                .foreach {
                p =>
                  if (isJavaAndNotJLObject(p.symbol)) printJava(p, "Templa")
                  p.tpe.typeArgs.foreach {
                    //FIMXE: Some classes like the numeric wrappers lack the "java.lang." part. Why?
                    typeArg => /*if (typeArg.toLongString.startsWith("java"))*/ println("TemplT " + typeArg.toLongString)
                  }
              }

            case _ =>
          }
        }

        println(occurrences + " occurrences found.")
      }

      def isJavaAndNotAccessor(mods: Modifiers, sym: Symbol): Boolean = sym != null && sym.isJavaDefined && !mods.hasAccessorFlag

      def isJavaAndNotJLObject(sym: Symbol): Boolean = sym.isJavaDefined && sym != definitions.ObjectClass

      private def printJava(tree: Tree, source: String) {
        val line = numbersWithThreeDigits(tree.pos.line)
        println(tree.pos.source + ":" + line + ": [" + source + "] " + " " + tree.symbol.fullName)

        occurrences += 1
      }

      var occurrences = 0

      def numbersWithThreeDigits(num: Int): String = {
        val l = num
        if (l < 10) "00" + l
        else if (l < 100) "0" + l
        else "" + l
      }

Maybe you have an idea.

Thanks!


Simon