Scala example source code file (DotDiagramGenerator.scala)

This example Scala source code file (DotDiagramGenerator.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

collection, elem, immutable, list, map, multisuffix, node, none, null, string, td, unprefixedattribute, xml

The DotDiagramGenerator.scala Scala example source code

/**
 * @author Damien Obrist
 * @author Vlad Ureche
 */
package scala
package tools
package nsc
package doc
package html
package page
package diagram

import scala.xml.{NodeSeq, XML, PrefixedAttribute, Elem, MetaData, Null, UnprefixedAttribute}
import scala.collection.immutable._
import model._
import model.diagram._

class DotDiagramGenerator(settings: doc.Settings) extends DiagramGenerator {

  // the page where the diagram will be embedded
  private var page: HtmlPage = null
  // path to the "lib" folder relative to the page
  private var pathToLib: String = null
  // maps nodes to unique indices
  private var node2Index: Map[Node, Int] = null
  // true if the current diagram is a class diagram
  private var isInheritanceDiagram = false
  // incoming implicit nodes (needed for determining the CSS class of a node)
  private var incomingImplicitNodes: List[Node] = List()
  // the suffix used when there are two many classes to show
  private final val MultiSuffix = " classes/traits"
  // used to generate unique node and edge ids (i.e. avoid conflicts with multiple diagrams)
  private var counter = 0

  def generate(diagram: Diagram, template: DocTemplateEntity, page: HtmlPage):NodeSeq = {
    counter = counter + 1
    this.page = page
    pathToLib = "../" * (page.templateToPath(template).size - 1) + "lib/"
    val dot = generateDot(diagram)
    val result = generateSVG(dot, template)
    // clean things up a bit, so we don't leave garbage on the heap
    this.page = null
    node2Index = null
    incomingImplicitNodes = List()
    result
  }

  /**
   * Generates a dot string for a given diagram.
   */
  private def generateDot(d: Diagram) = {
    // inheritance nodes (all nodes except thisNode and implicit nodes)
    var nodes: List[Node] = null
    // inheritance edges (all edges except implicit edges)
    var edges: List[(Node, List[Node])] = null

    // timing
    var tDot = -System.currentTimeMillis

    // variables specific to class diagrams:
    // current node of a class diagram
    var thisNode:Node = null
    var subClasses = List[Node]()
    var superClasses = List[Node]()
    var incomingImplicits = List[Node]()
    var outgoingImplicits = List[Node]()
    isInheritanceDiagram = false

    d match {
      case InheritanceDiagram(_thisNode, _superClasses, _subClasses, _incomingImplicits, _outgoingImplicits) =>

        def textTypeEntity(text: String) =
          new TypeEntity {
            val name = text
            def refEntity: SortedMap[Int, (base.LinkTo, Int)] = SortedMap()
          }

        // it seems dot chokes on node names over 8000 chars, so let's limit the size of the string
        // conservatively, we'll limit at 4000, to be sure:
        def limitSize(str: String) = if (str.length > 4000) str.substring(0, 3996) + " ..." else str

        // avoid overcrowding the diagram:
        //   if there are too many super / sub / implicit nodes, represent
        //   them by on node with a corresponding tooltip
        superClasses = if (_superClasses.length > settings.docDiagramsMaxNormalClasses.value) {
          val superClassesTooltip = Some(limitSize(_superClasses.map(_.tpe.name).mkString(", ")))
          List(NormalNode(textTypeEntity(_superClasses.length + MultiSuffix), None)(superClassesTooltip))
        } else _superClasses

        subClasses = if (_subClasses.length > settings.docDiagramsMaxNormalClasses.value) {
          val subClassesTooltip = Some(limitSize(_subClasses.map(_.tpe.name).mkString(", ")))
          List(NormalNode(textTypeEntity(_subClasses.length + MultiSuffix), None)(subClassesTooltip))
        } else _subClasses

        incomingImplicits = if (_incomingImplicits.length > settings.docDiagramsMaxImplicitClasses.value) {
          val incomingImplicitsTooltip = Some(limitSize(_incomingImplicits.map(_.tpe.name).mkString(", ")))
          List(ImplicitNode(textTypeEntity(_incomingImplicits.length + MultiSuffix), None)(incomingImplicitsTooltip))
        } else _incomingImplicits

        outgoingImplicits = if (_outgoingImplicits.length > settings.docDiagramsMaxImplicitClasses.value) {
          val outgoingImplicitsTooltip = Some(limitSize(_outgoingImplicits.map(_.tpe.name).mkString(", ")))
          List(ImplicitNode(textTypeEntity(_outgoingImplicits.length + MultiSuffix), None)(outgoingImplicitsTooltip))
        } else _outgoingImplicits

        thisNode = _thisNode
        nodes = List()
        edges = (thisNode -> superClasses) :: subClasses.map(_ -> List(thisNode))
        node2Index = (thisNode::subClasses:::superClasses:::incomingImplicits:::outgoingImplicits).zipWithIndex.toMap
        isInheritanceDiagram = true
        incomingImplicitNodes = incomingImplicits
      case _ =>
        nodes = d.nodes
        edges = d.edges
        node2Index = d.nodes.zipWithIndex.toMap
        incomingImplicitNodes = List()
    }

    val implicitsDot = {
      if (!isInheritanceDiagram) ""
      else {
        // dot cluster containing thisNode
        val thisCluster = "subgraph clusterThis {\n" +
          "style=\"invis\"\n" +
          node2Dot(thisNode) +
        "}"
        // dot cluster containing incoming implicit nodes, if any
        val incomingCluster = {
          if(incomingImplicits.isEmpty) ""
          else "subgraph clusterIncoming {\n" +
            "style=\"invis\"\n" +
            incomingImplicits.reverse.map(n => node2Dot(n)).mkString +
            (if (incomingImplicits.size > 1)
              incomingImplicits.map(n => "node" + node2Index(n)).mkString(" -> ") +
              " [constraint=\"false\", style=\"invis\", minlen=\"0.0\"];\n"
            else "") +
          "}"
        }
        // dot cluster containing outgoing implicit nodes, if any
        val outgoingCluster = {
          if(outgoingImplicits.isEmpty) ""
          else "subgraph clusterOutgoing {\n" +
            "style=\"invis\"\n" +
            outgoingImplicits.reverse.map(n => node2Dot(n)).mkString +
            (if (outgoingImplicits.size > 1)
              outgoingImplicits.map(n => "node" + node2Index(n)).mkString(" -> ") +
              " [constraint=\"false\", style=\"invis\", minlen=\"0.0\"];\n"
            else "") +
          "}"
        }

        // assemble clusters into another cluster
        val incomingTooltip = incomingImplicits.map(_.name).mkString(", ") + " can be implicitly converted to " + thisNode.name
        val outgoingTooltip =  thisNode.name + " can be implicitly converted to " + outgoingImplicits.map(_.name).mkString(", ")
        "subgraph clusterAll {\n" +
      	"style=\"invis\"\n" +
          outgoingCluster + "\n" +
      	  thisCluster + "\n" +
      	  incomingCluster + "\n" +
      	  // incoming implicit edge
      	  (if (!incomingImplicits.isEmpty) {
      	    val n = incomingImplicits.last
      	    "node" + node2Index(n) +" -> node" + node2Index(thisNode) +
      	    " [id=\"" + cssClass(n, thisNode) + "|" + node2Index(n) + "_" + node2Index(thisNode) + "\", tooltip=\"" + incomingTooltip + "\"" +
      	    ", constraint=\"false\", minlen=\"2\", ltail=\"clusterIncoming\", lhead=\"clusterThis\", label=\"implicitly\"];\n"
      	  } else "") +
      	  // outgoing implicit edge
      	  (if (!outgoingImplicits.isEmpty) {
      	    val n = outgoingImplicits.head
      	    "node" + node2Index(thisNode) + " -> node" + node2Index(n) +
      	    " [id=\"" + cssClass(thisNode, n) + "|" + node2Index(thisNode) + "_" + node2Index(n) + "\", tooltip=\"" + outgoingTooltip + "\"" +
      	    ", constraint=\"false\", minlen=\"2\", ltail=\"clusterThis\", lhead=\"clusterOutgoing\", label=\"implicitly\"];\n"
      	  } else "") +
        "}"
      }
    }

    // assemble graph
    val graph = "digraph G {\n" +
      // graph / node / edge attributes
      graphAttributesStr +
      "node [" + nodeAttributesStr + "];\n" +
      "edge [" + edgeAttributesStr + "];\n" +
      implicitsDot + "\n" +
      // inheritance nodes
      nodes.map(n => node2Dot(n)).mkString +
      subClasses.map(n => node2Dot(n)).mkString +
      superClasses.map(n => node2Dot(n)).mkString +
      // inheritance edges
      edges.map{ case (from, tos) => tos.map(to => {
        val id = "graph" + counter + "_" + node2Index(to) + "_" + node2Index(from)
        // the X -> Y edge is inverted twice to keep the diagram flowing the right way
        // that is, an edge from node X to Y will result in a dot instruction nodeY -> nodeX [dir="back"]
        "node" + node2Index(to) + " -> node" + node2Index(from) +
        " [id=\"" + cssClass(to, from) + "|" + id + "\", " +
        "tooltip=\"" + from.name + (if (from.name.endsWith(MultiSuffix)) " are subtypes of " else " is a subtype of ") +
          to.name + "\", dir=\"back\", arrowtail=\"empty\"];\n"
      }).mkString}.mkString +
    "}"

    tDot += System.currentTimeMillis
    DiagramStats.addDotGenerationTime(tDot)

    graph
  }

  /**
   * Generates the dot string of a given node.
   */
  private def node2Dot(node: Node) = {

    // escape HTML characters in node names
    def escape(name: String) = name.replace("&", "&").replace("<", "<").replace(">", ">")

    // assemble node attribues in a map
    val attr = scala.collection.mutable.Map[String, String]()

    // link
    node.doctpl match {
      case Some(tpl) => attr += "URL" -> (page.relativeLinkTo(tpl) + "#inheritance-diagram")
      case _ =>
    }

    // tooltip
    node.tooltip match {
      case Some(text) => attr += "tooltip" -> text
      // show full name where available (instead of TraversableOps[A] show scala.collection.parallel.TraversableOps[A])
      case None if node.tpl.isDefined => attr += "tooltip" -> node.tpl.get.qualifiedName
      case _ =>
    }

    // styles
    if(node.isImplicitNode)
      attr ++= implicitStyle
    else if(node.isOutsideNode)
      attr ++= outsideStyle
    else if(node.isTraitNode)
      attr ++= traitStyle
    else if(node.isClassNode)
      attr ++= classStyle
    else if(node.isObjectNode)
      attr ++= objectStyle
    else if(node.isTypeNode)
      attr ++= typeStyle
    else
      attr ++= defaultStyle

    // HTML label
    var name = escape(node.name)
    var img = ""
    if(node.isTraitNode)
      img = "trait_diagram.png"
    else if(node.isClassNode)
      img = "class_diagram.png"
    else if(node.isObjectNode)
      img = "object_diagram.png"
    else if(node.isTypeNode)
      img = "type_diagram.png"

    if(!img.equals("")) {
      img = "<TD><IMG SCALE=\"TRUE\" SRC=\"" + settings.outdir.value + "/lib/" + img + "\" /></TD>"
      name = name + " "
    }
    val label = "<<TABLE BORDER=\"0\" CELLBORDER=\"0\">" +
    		       "<TR>" + img + "<TD VALIGN=\"MIDDLE\">" + name + "</TD></TR>" +
    		    "</TABLE>>"

    // dot does not allow to specify a CSS class, therefore
    // set the id to "{class}|{id}", which will be used in
    // the transform method
    val id = "graph" + counter + "_" + node2Index(node)
    attr += ("id" -> (cssClass(node) + "|" + id))

    // return dot string
    "node" + node2Index(node) + " [label=" + label + "," + flatten(attr.toMap) + "];\n"
  }

  /**
   * Returns the CSS class for an edge connecting node1 and node2.
   */
  private def cssClass(node1: Node, node2: Node): String = {
    if (node1.isImplicitNode && node2.isThisNode)
      "implicit-incoming"
    else if (node1.isThisNode && node2.isImplicitNode)
      "implicit-outgoing"
    else
      "inheritance"
  }

  /**
   * Returns the CSS class for a node.
   */
  private def cssClass(node: Node): String =
    if (node.isImplicitNode && incomingImplicitNodes.contains(node))
      "implicit-incoming" + cssBaseClass(node, "", " ")
    else if (node.isImplicitNode)
      "implicit-outgoing" + cssBaseClass(node, "", " ")
    else if (node.isThisNode)
      "this" + cssBaseClass(node, "", " ")
    else if (node.isOutsideNode)
      "outside" + cssBaseClass(node, "", " ")
    else
      cssBaseClass(node, "default", "")

  private def cssBaseClass(node: Node, default: String, space: String) =
    if (node.isClassNode)
      space + "class"
    else if (node.isTraitNode)
      space + "trait"
    else if (node.isObjectNode)
      space + "object"
    else if (node.isTypeNode)
      space + "type"
    else
      default

  /**
   * Calls dot with a given dot string and returns the SVG output.
   */
  private def generateSVG(dotInput: String, template: DocTemplateEntity) = {
    val dotOutput = DiagramGenerator.getDotRunner().feedToDot(dotInput, template)
    var tSVG = -System.currentTimeMillis

    val result = if (dotOutput != null) {
      val src = scala.io.Source.fromString(dotOutput)
      try {
        val cpa = scala.xml.parsing.ConstructingParser.fromSource(src, preserveWS = false)
        val doc = cpa.document()
        if (doc != null)
          transform(doc.docElem)
        else
          NodeSeq.Empty
      } catch {
        case exc: Exception =>
          if (settings.docDiagramsDebug) {
            settings.printMsg("\n\n**********************************************************************")
            settings.printMsg("Encountered an error while generating page for " + template.qualifiedName)
            settings.printMsg(dotInput.toString.split("\n").mkString("\nDot input:\n\t","\n\t",""))
            settings.printMsg(dotOutput.toString.split("\n").mkString("\nDot output:\n\t","\n\t",""))
            settings.printMsg(exc.getStackTrace.mkString("\nException: " + exc.toString + ":\n\tat ", "\n\tat ",""))
            settings.printMsg("\n\n**********************************************************************")
          } else {
            settings.printMsg("\nThe diagram for " + template.qualifiedName + " could not be created due to an internal error.")
            settings.printMsg("Use " + settings.docDiagramsDebug.name + " for more information and please file this as a bug.")
          }
          NodeSeq.Empty
      }
    } else
      NodeSeq.Empty

    tSVG += System.currentTimeMillis
    DiagramStats.addSvgTime(tSVG)

    result
  }

  /**
   * Transforms the SVG generated by dot:
   * - adds a class attribute to the SVG element
   * - changes the path of the node images from absolute to relative
   * - assigns id and class attributes to nodes and edges
   * - removes title elements
   */
  private def transform(e:scala.xml.Node): scala.xml.Node = e match {
    // add an id and class attribute to the SVG element
    case Elem(prefix, "svg", attribs, scope, child @ _*) => {
      val klass = if (isInheritanceDiagram) "class-diagram" else "package-diagram"
      Elem(prefix, "svg", attribs, scope, child map(x => transform(x)) : _*) %
      new UnprefixedAttribute("id", "graph" + counter, Null) %
      new UnprefixedAttribute("class", klass, Null)
    }
    // change the path of the node images from absolute to relative
    case img @ <image></image> => {
      val href = (img \ "@{http://www.w3.org/1999/xlink}href").toString
      val file = href.substring(href.lastIndexOf("/") + 1, href.size)
      img.asInstanceOf[Elem] %
      new PrefixedAttribute("xlink", "href", pathToLib + file, Null)
    }
    // assign id and class attributes to edges and nodes:
    // the id attribute generated by dot has the format: "{class}|{id}"
    case g @ Elem(prefix, "g", attribs, scope, children @ _*) if (List("edge", "node").contains((g \ "@class").toString)) => {
      var res = new Elem(prefix, "g", attribs, scope, (children map(x => transform(x))): _*)
      val dotId = (g \ "@id").toString
      if (dotId.count(_ == '|') == 1) {
        val Array(klass, id) = dotId.toString.split("\\|")
        /* Sometimes dot "forgets" to add the image -- that's very annoying, but it seems pretty random, and simple
         * tests like excute 20K times and diff the output don't trigger the bug -- so it's up to us to place the image
         * back in the node */
        val kind = getKind(klass)
        if (kind != "")
          if (((g \ "a" \ "image").isEmpty)) {
            DiagramStats.addBrokenImage()
            val xposition = getPosition(g, "x", -22)
            val yposition = getPosition(g, "y", -11.3334)
            if (xposition.isDefined && yposition.isDefined) {
              val imageNode = <image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href={ ("./lib/" + kind + "_diagram.png") } width="16px" height="16px" preserveAspectRatio="xMinYMin meet" x={ xposition.get.toString } y={ yposition.get.toString }/>
              val anchorNode = (g \ "a") match {
                case Seq(Elem(prefix, "a", attribs, scope, children @ _*)) =>
                  transform(new Elem(prefix, "a", attribs, scope, (children ++ imageNode): _*))
                case _ =>
                  g \ "a"
              }
              res = new Elem(prefix, "g", attribs, scope, anchorNode: _*)
              DiagramStats.addFixedImage()
            }
          }
        res % new UnprefixedAttribute("id", id, Null) %
        new UnprefixedAttribute("class", (g \ "@class").toString + " " + klass, Null)
      }
      else res
    }
    // remove titles
    case <title>{ _* }</title> =>
      scala.xml.Text("")
    // apply recursively
    case Elem(prefix, label, attribs, scope, child @ _*) =>
      Elem(prefix, label, attribs, scope, child map(x => transform(x)) : _*)
    case x => x
  }

  def getKind(klass: String): String =
    if (klass.contains("class")) "class"
    else if (klass.contains("trait")) "trait"
    else if (klass.contains("object")) "object"
    else ""

  def getPosition(g: scala.xml.Node, axis: String, offset: Double): Option[Double] = {
    val node = g \ "a" \ "text" \ ("@" + axis)
    if (node.isEmpty)
      None
    else
      Some(node.toString.toDouble + offset)
  }

  /* graph / node / edge attributes */

  private val graphAttributes: Map[String, String] = Map(
      "compound" -> "true",
      "rankdir" -> "TB"
  )

  private val nodeAttributes = Map(
    "shape" -> "rectangle",
    "style" -> "filled",
    "penwidth" -> "1",
    "margin" -> "0.08,0.01",
    "width" -> "0.0",
    "height" -> "0.0",
    "fontname" -> "Arial",
    "fontsize" -> "10.00"
  )

  private val edgeAttributes = Map(
    "color" -> "#d4d4d4",
    "arrowsize" -> "0.5",
    "fontcolor" -> "#aaaaaa",
    "fontsize" -> "10.00",
    "fontname" -> "Arial"
  )

  private val defaultStyle = Map(
    "color" -> "#ababab",
    "fillcolor" -> "#e1e1e1",
    "fontcolor" -> "#7d7d7d",
    "margin" -> "0.1,0.04"
  )

  private val implicitStyle = Map(
    "color" -> "#ababab",
    "fillcolor" -> "#e1e1e1",
    "fontcolor" -> "#7d7d7d"
  )

  private val outsideStyle = Map(
    "color" -> "#ababab",
    "fillcolor" -> "#e1e1e1",
    "fontcolor" -> "#7d7d7d"
  )

  private val traitStyle = Map(
    "color" -> "#37657D",
    "fillcolor" -> "#498AAD",
    "fontcolor" -> "#ffffff"
  )

  private val classStyle = Map(
    "color" -> "#115F3B",
    "fillcolor" -> "#0A955B",
    "fontcolor" -> "#ffffff"
  )

  private val objectStyle = Map(
    "color" -> "#102966",
    "fillcolor" -> "#3556a7",
    "fontcolor" -> "#ffffff"
  )

  private val typeStyle = Map(
    "color" -> "#115F3B",
    "fillcolor" -> "#0A955B",
    "fontcolor" -> "#ffffff"
  )

  private def flatten(attributes: Map[String, String]) = attributes.map{ case (key, value) => key + "=\"" + value + "\"" }.mkString(", ")

  private val graphAttributesStr = graphAttributes.map{ case (key, value) => key + "=\"" + value + "\";\n" }.mkString
  private val nodeAttributesStr = flatten(nodeAttributes)
  private val edgeAttributesStr = flatten(edgeAttributes)
}