Scala example source code file (ValidatingMarkupHandler.scala)

This example Scala source code file (ValidatingMarkupHandler.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

attlistdecl, dtd, dtd, elemdecl, elements, externalid, int, int, list, list, logged, nil, string, string

The Scala ValidatingMarkupHandler.scala source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2002-2011, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */



package scala.xml
package parsing

import scala.xml.dtd._
import scala.util.logging.Logged

abstract class ValidatingMarkupHandler extends MarkupHandler with Logged {

  var rootLabel:String = _
  var qStack: List[Int] = Nil
  var qCurrent: Int = -1

  var declStack: List[ElemDecl] = Nil
  var declCurrent: ElemDecl = null

  final override val isValidating = true

  override def log(msg: String) {}
  
  /*
  override def checkChildren(pos: Int, pre: String, label:String,ns:NodeSeq): Unit = {
    Console.println("checkChildren()");
    val decl = lookupElemDecl(label);
    // @todo: nice error message
    val res = decl.contentModel.validate(ns);
    Console.println("res = "+res);
    if(!res)
      //sys.error("invalid!");
  }
  */

  override def endDTD(n:String) = {
    rootLabel = n
  }
  override def elemStart(pos: Int, pre: String, label: String, attrs: MetaData, scope:NamespaceBinding) {

    def advanceDFA(dm:DFAContentModel) = {
      val trans = dm.dfa.delta(qCurrent)
      log("advanceDFA(dm): " + dm)
      log("advanceDFA(trans): " + trans)
      trans.get(ContentModel.ElemName(label)) match {
          case Some(qNew) => qCurrent = qNew
          case _          => reportValidationError(pos, "DTD says, wrong element, expected one of "+trans.keys);
        }
    }
    // advance in current automaton
    log("[qCurrent = "+qCurrent+" visiting "+label+"]")

    if (qCurrent == -1) { // root
      log("  checking root")
      if (label != rootLabel)
        reportValidationError(pos, "this element should be "+rootLabel)
    } else {
      log("  checking node")
      declCurrent.contentModel match {
        case ANY =>
        case EMPTY => 
          reportValidationError(pos, "DTD says, no elems, no text allowed here")
        case PCDATA => 
          reportValidationError(pos, "DTD says, no elements allowed here")
        case m @ MIXED(r) =>
          advanceDFA(m)
        case e @ ELEMENTS(r) =>
          advanceDFA(e)
      }
    }
    // push state, decl
    qStack    =    qCurrent :: qStack
    declStack = declCurrent :: declStack

    declCurrent = lookupElemDecl(label)
    qCurrent = 0
    log("  done  now")
  }

  override def elemEnd(pos: Int, pre: String, label: String) {
    log("  elemEnd")
    qCurrent = qStack.head
    qStack   = qStack.tail
    declCurrent = declStack.head
    declStack   = declStack.tail
    log("    qCurrent now" + qCurrent)
    log("    declCurrent now" + declCurrent)
  }

  final override def elemDecl(name: String, cmstr: String) {
    decls = ElemDecl(name, ContentModel.parse(cmstr)) :: decls
  }
    
  final override def attListDecl(name: String, attList: List[AttrDecl]) {
    decls = AttListDecl(name, attList) :: decls
  }

  final override def unparsedEntityDecl(name: String, extID: ExternalID, notat: String) {
    decls = UnparsedEntityDecl(name, extID, notat) :: decls
  }

  final override def notationDecl(notat: String, extID: ExternalID) {
    decls = NotationDecl(notat, extID) :: decls;
  }

  final override def peReference(name: String) {
    decls = PEReference(name) :: decls
  }

  /** report a syntax error */
  def reportValidationError(pos: Int, str: String): Unit

}