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Scala example source code file (XIncluder.scala)

This example Scala source code file (XIncluder.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

array, doctype, int, int, io, ioexception, lexicalhandler, sax, saxexception, saxexception, string, string, system, write, write, xincludefilter

The Scala XIncluder.scala source code

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


package scala.xml
package include.sax

import scala.xml.include._
import collection.mutable.Stack

import org.xml.sax.{ ContentHandler, XMLReader, Locator, Attributes }
import org.xml.sax.ext.LexicalHandler
import java.io.{ File, OutputStream, OutputStreamWriter, Writer, IOException }

/** XIncluder is a SAX <code>ContentHandler 
 * that writes its XML document onto an output stream after resolving
 * all <code>xinclude:include elements.
 *
 * <p>
 *   based on Eliotte Rusty Harold's SAXXIncluder
 * </p>
 */
class XIncluder(outs: OutputStream, encoding: String) extends ContentHandler with LexicalHandler {

  var out = new OutputStreamWriter(outs, encoding)

  def setDocumentLocator(locator: Locator) {}
    
  def startDocument() {
    try {
      out.write("<?xml version='1.0' encoding='" 
                + encoding + "'?>\r\n");
    }
    catch {
      case e:IOException =>
        throw new SAXException("Write failed", e)
    }        
  }

  def endDocument() {
    try {
      out.flush()
    }
    catch { 
      case e:IOException =>
        throw new SAXException("Flush failed", e)
    }
  }
    
  def startPrefixMapping(prefix: String , uri: String) {}
    
  def endPrefixMapping(prefix: String) {}

  def startElement(namespaceURI: String, localName: String, qualifiedName: String, atts: Attributes) = {
    try {
      out.write("<" + qualifiedName);
      var i = 0; while (i < atts.getLength()) {
        out.write(" ");   
        out.write(atts.getQName(i));   
        out.write("='");
        val value = atts.getValue(i);
        // @todo Need to use character references if the encoding
        // can't support the character
        out.write(xml.Utility.escape(value))
        out.write("'");
        i += 1
      }
      out.write(">")
    }
    catch { 
      case e:IOException =>
        throw new SAXException("Write failed", e)
    }        
  }
  
  def endElement(namespaceURI: String, localName:String, qualifiedName: String) {
    try {
      out.write("</" + qualifiedName + ">")
    }
    catch {
      case e: IOException =>
        throw new SAXException("Write failed", e)
    }
  }

  // need to escape characters that are not in the given 
  // encoding using character references????
  def characters(ch: Array[Char], start: Int, length: Int) {
    try {
      var  i = 0; while (i < length) {
        val c = ch(start+i);
        if (c == '&') out.write("&");
        else if (c == '<') out.write("<");
        // This next fix is normally not necessary.
        // However, it is required if text contains ]]>
        // (The end CDATA section delimiter)
        else if (c == '>') out.write(">");
        else out.write(c);
        i = i+1;
      }
    }
    catch { 
      case e: IOException => 
        throw new SAXException("Write failed", e);      
    }
  }

  def  ignorableWhitespace(ch: Array[Char], start: Int , length: Int) {
    this.characters(ch, start, length)
  }
  
  // do I need to escape text in PI????
  def processingInstruction(target: String, data: String) {
    try {
      out.write("<?" + target + " " + data + "?>")
    }
    catch { 
      case e:IOException =>
        throw new SAXException("Write failed", e)
    }
  }
  
  def skippedEntity(name: String) {
    try {
      out.write("&" + name + ";")
    }
    catch {
      case e:IOException =>
        throw new SAXException("Write failed", e)
    }
  }

  // LexicalHandler methods
  private var inDTD: Boolean = false
  private val entities = new Stack[String]()

  def startDTD(name: String, publicID: String, systemID: String) {
    inDTD = true
    // if this is the source document, output a DOCTYPE declaration
    if (entities.isEmpty) {
      var id = ""
      if (publicID != null) id = " PUBLIC \"" + publicID + "\" \"" + systemID + '"';
      else if (systemID != null) id = " SYSTEM \"" + systemID + '"';
      try {
        out.write("<!DOCTYPE " + name + id + ">\r\n")
      }
      catch { 
        case e:IOException =>
          throw new SAXException("Error while writing DOCTYPE", e)
      }
    }
  }
  def endDTD() {}
    
  def startEntity(name: String) {
    entities push name
  }

  def endEntity(name: String) {
    entities.pop()
  }

  def startCDATA() {}
  def endCDATA() {}

  // Just need this reference so we can ask if a comment is 
  // inside an include element or not
  private var filter: XIncludeFilter = null
  
  def setFilter(filter: XIncludeFilter) {
    this.filter = filter
  }

  def comment(ch: Array[Char], start: Int, length: Int) {
    if (!inDTD && !filter.insideIncludeElement()) {
      try {
        out.write("<!--")
        out.write(ch, start, length)
        out.write("-->")
      }
      catch { 
        case e: IOException =>
          throw new SAXException("Write failed", e)
      }
    }
  }
}

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