Scala example source code file (javasigs.scala)

This example Scala source code file (javasigs.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

a, array, b, b, bufferedreader, bufferedreader, c, c, filewriter, innerb, io, slurp, string, string, xprint

The Scala javasigs.scala source code

import java.io._

object Scalatest {
  val outputdir = System.getProperty("partest.output", "inner.obj")
  val scalalib  = System.getProperty("partest.lib", "")
  val classpath = outputdir + File.pathSeparator + scalalib
  val javacmd   = System.getProperty("javacmd", "java")
  val javac     = System.getProperty("javaccmd", "javac")

  def javac(src: String, opts: String, fname: String) {
    val tmpfilename = outputdir + File.separator + fname
    val tmpfile = new FileWriter(tmpfilename)
    tmpfile.write(src)
    tmpfile.close
    exec(javac + " -d " + outputdir + " -classpath " + classpath + " " + opts + tmpfilename)
  }

  def java(cname: String) =
    exec(javacmd + " -cp " + classpath + " " + cname)

  class Slurp(in: BufferedReader) extends Thread("slurper") {
    var done = false
    override def run() {
      while (!done)  if (in.ready) println(in.readLine())
    }
  }

  def slurp(in: BufferedReader): Slurp = {
    val s = new Slurp(in)
    s.start()
    s
  }
    

  /** Execute cmd, wait for the process to end and pipe it's output to stdout */
  def exec(cmd: String) {
    val proc = Runtime.getRuntime().exec(cmd)
    val inp = new BufferedReader(new InputStreamReader(proc.getInputStream))
    val errp = new BufferedReader(new InputStreamReader(proc.getErrorStream))
    val t1 = slurp(inp)
    val t2 = slurp(errp)
    proc.waitFor()
    t1.done = true
    t2.done = true
    t1.join()
    t2.join()
  }
}

// Test correct java signatures for anonymous classes. Enclosing method attributes should
// allow javac to see the type parameters in foo. See #3249.

class A[U] { 
   def bar[B](x : => B) = x
   def foo[C](c : C) : C = bar(c)
}

object B { 
   def bar[B](x : => B) = x
   def foo[C](c : C) : C = {
     class InnerB(x: C)
     c
   }
}

class B {
  def foo {}
}

object Test {
  def main(args: Array[String]) {
    import Scalatest._
    exec("%s -Xprint -cp %s A".format(javac, classpath))
    exec("%s -Xprint -cp %s B".format(javac, classpath))
    exec("%s -Xprint -cp %s A$$anonfun$foo$1".format(javac, classpath))
    exec("%s -Xprint -cp %s scala.actors.Actor".format(javac, classpath))
  }
}