Render class diagram with Graphviz

1.md

This example models a class diagram with Scuml and then uses Graphviz to render the class diagram.

2.png

dot.scala

import scuml._

// helper object for using the Graphviz command line utility
object Graphviz {
  import java.io._
  import actors.Actor
  import actors.Actor._

  def apply(dot: String): File = {
    val p = Runtime.getRuntime.exec("dot -Tpng")
    val writer = actor {
      receive {
        case 'Write =>
          val w = new BufferedWriter(new OutputStreamWriter(p.getOutputStream))
          w write dot
          w.newLine
          w.close
          exit
      }
    }
    val reader = actor {
      receive {
        case 'Read =>
          val f = File.createTempFile("scuml", "")
          val out = new FileOutputStream(f)
          val buffer = new Array[Byte](1024)
          Stream.continually(p.getInputStream.read(buffer)).takeWhile(_ != -1).foreach(out.write(buffer, 0, _))
          p.waitFor
          reply { f }
          exit
      }
    }
    writer ! 'Write
    val f = reader !? 'Read
    f.asInstanceOf[File]
  }
}

sample.scala

import scuml._

// create a Diagram with the DSL
val element = "Element" % "abstract" % "sealed"
val node = "Node" % "case"
val edge = "Edge" % "case"
val group = "Group" % "case"
val anchor = "Anchor" % "case"

val diagram = Diagram(
  "Diagram" % "case" :>> "+" === ">" <<: "0..*" <*: element,
  node === "^" <<: element,
  edge === "^" <<: element,
  group === "^" <<: element,
  edge :*> "source" === ">" <<: anchor,
  edge :*> "destination" === ">" <<: anchor,
  anchor === ">" <<: node,
  group :>> "+" === ">" <<: "0..*" <*: node)

// render in DOT format and create an image with the help of Graphviz
val dot = diagram.toDot
val f = Graphviz(dot)
java.awt.Desktop.getDesktop.open(f)