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Scala example source code file (ContentModel.scala)

This example Scala source code file (ContentModel.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

alt, any, contentmodel, contentmodel, elemname, empty, pcdata, pcdata, regexp, regexp, set, string, stringbuilder, stringbuilder

The Scala ContentModel.scala source code

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



package scala.xml
package dtd

import util.regexp.WordExp
import util.automata._
import Utility.sbToString
import PartialFunction._

object ContentModel extends WordExp {
  type _labelT = ElemName
  type _regexpT = RegExp

  object Translator extends WordBerrySethi {
    override val lang: ContentModel.this.type = ContentModel.this
  }

  case class ElemName(name: String) extends Label {
    override def toString() = """ElemName("%s")""" format name
  }

  def isMixed(cm: ContentModel) = cond(cm) { case _: MIXED => true }
  def containsText(cm: ContentModel) = (cm == PCDATA) || isMixed(cm)
  def parse(s: String): ContentModel = ContentModelParser.parse(s)

  def getLabels(r: RegExp): Set[String] = {    
    def traverse(r: RegExp): Set[String] = r match { // !!! check for match translation problem
      case Letter(ElemName(name)) => Set(name)
      case Star(  x @ _  ) => traverse( x ) // bug if x@_*
      case Sequ( xs @ _* ) => Set(xs map traverse flatten: _*)
      case Alt(  xs @ _* ) => Set(xs map traverse flatten: _*)
    }
    
    traverse(r)
  }

  def buildString(r: RegExp): String = sbToString(buildString(r, _))

  /* precond: rs.length >= 1 */
  private def buildString(rs: Seq[RegExp], sb: StringBuilder, sep: Char) {
    buildString(rs.head, sb)
    for (z <- rs.tail) {
      sb append sep
      buildString(z, sb)
    }
    sb
  }

  def buildString(c: ContentModel, sb: StringBuilder): StringBuilder = c match {
    case ANY                    => sb append "ANY"
    case EMPTY                  => sb append "EMPTY"
    case PCDATA                 => sb append "(#PCDATA)"
    case ELEMENTS(_) | MIXED(_) => c buildString sb
  }

  def buildString(r: RegExp, sb: StringBuilder): StringBuilder =
    r match {  // !!! check for match translation problem
      case Eps => 
        sb
      case Sequ(rs @ _*) => 
        sb.append( '(' ); buildString(rs, sb, ','); sb.append( ')' )
      case Alt(rs @ _*) =>
        sb.append( '(' ); buildString(rs, sb, '|');  sb.append( ')' )
      case Star(r: RegExp) => 
        sb.append( '(' ); buildString(r, sb); sb.append( ")*" )
      case Letter(ElemName(name)) =>
        sb.append(name)
    }

}

sealed abstract class ContentModel
{
  override def toString(): String = sbToString(buildString)
  def buildString(sb: StringBuilder): StringBuilder
}

case object PCDATA extends ContentModel {
  override def buildString(sb: StringBuilder): StringBuilder = sb.append("(#PCDATA)")
}
case object EMPTY extends ContentModel {
  override def buildString(sb: StringBuilder): StringBuilder = sb.append("EMPTY")
}
case object ANY extends ContentModel {
  override def buildString(sb: StringBuilder): StringBuilder = sb.append("ANY")
}
sealed abstract class DFAContentModel extends ContentModel {
  import ContentModel.{ ElemName, Translator }
  def r: ContentModel.RegExp
  
  lazy val dfa: DetWordAutom[ElemName] = {
    val nfa = Translator.automatonFrom(r, 1)
    new SubsetConstruction(nfa).determinize
  }
}

case class MIXED(r: ContentModel.RegExp) extends DFAContentModel {
  import ContentModel.{ Alt, RegExp }

  override def buildString(sb: StringBuilder): StringBuilder = {
    val newAlt = r match { case Alt(rs @ _*) => Alt(rs drop 1: _*) }

    sb append "(#PCDATA|"
    ContentModel.buildString(newAlt: RegExp, sb)
    sb append ")*"
  }
}

case class ELEMENTS(r: ContentModel.RegExp) extends DFAContentModel {
  override def buildString(sb: StringBuilder): StringBuilder =  
    ContentModel.buildString(r, sb)
}

Other Scala examples (source code examples)

Here is a short list of links related to this Scala ContentModel.scala source code file:

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