////////////////////////////////////////////////////////////////////////////////
   // MillScript-XML: an Open Spice interpreter and batch website creation tool
   // Copyright (C) 2005 Kevin Rogers
   //
   // This file is part of MillScript-XML.
   //
   // MillScript-XML is free software; you can redistribute it and/or modify it under
   // the terms of the GNU General Public License as published by the Free
   // Software Foundation; either version 2 of the License, or (at your option)
  // any later version.
  //
  // MillScript-XML is distributed in the hope that it will be useful, but WITHOUT
  // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  // more details.
  //
  // You should have received a copy of the GNU General Public License along with
  // MillScript-XML; if not, write to the Free Software Foundation, Inc., 59 Temple
  // Place, Suite 330, Boston, MA  02111-1307  USA
  ////////////////////////////////////////////////////////////////////////////////
  package org.millscript.commons.xml.tokenizer.wellformed;
  
  import org.millscript.commons.xml.alerts.XmlWellFormednessAlert;
  import org.millscript.commons.xml.api.token.CharDataToken;
  import org.millscript.commons.xml.api.token.CommentToken;
  import org.millscript.commons.xml.api.token.DTDToken;
  import org.millscript.commons.xml.api.token.EmptyElementToken;
  import org.millscript.commons.xml.api.token.EndTagToken;
  import org.millscript.commons.xml.api.token.PIToken;
  import org.millscript.commons.xml.api.token.StartTagToken;
  import org.millscript.commons.xml.api.token.TokenVisitor;
  
  /**
   * This class provides a token visitor the for <code>content</code> part of an
   * XML document. This is the a sub token visitor of the <code>element</code>
   * token visitor, in the chain that provides the well formedness checks
   * required of an XML processor.
   */
  public class ContentTokenVisitor extends AbsTokenVisitor {
  
      /**
       * The start tag token that begins this content section.
       */
      private final StartTagToken startTagToken;
  
      /**
       * Constructs a new <code>content</code> section token visitor, with the
       * specified tokenizer, next-in-the-chain token visitor and start tag.
       *
       * @param xt    the well-formed XML tokenizer our tokens come from
       * @param p the next token visitor in the well-formedness chain
       * @param stToken   the start tag token for the tag that began this content
       * section
       */
      public ContentTokenVisitor( final WellFormedXmlTokenizer xt, final TokenVisitor p, final StartTagToken stToken ) {
          // We set the "next" token visitor to the parent one, i.e. the one that
          // we should return to when we find the end tag for this content
          super( xt, p );
          this.startTagToken = stToken;
      }
  
      /**
       * @see org.millscript.commons.xml.api.token.TokenVisitor#visit(org.millscript.commons.xml.api.token.CharDataToken)
       */
      public void visit( final CharDataToken token ) {
          // this token is valid in this section
          this.wellFormed.nextToken = token;
      }
  
      /**
       * @see org.millscript.commons.xml.api.token.TokenVisitor#visit(org.millscript.commons.xml.api.token.CommentToken)
       */
      public void visit( final CommentToken token ) {
          // this token is valid in this section
          this.wellFormed.nextToken = token;
      }
  
      /**
       * @see org.millscript.commons.xml.api.token.TokenVisitor#visit(org.millscript.commons.xml.api.token.DTDToken)
       */
      public void visit( final DTDToken token ) {
          throw new XmlWellFormednessAlert(
              "Only one document type declaration can be used in a single XML document"
          ).decorate( token ).mishap();
      }
  
      /**
       * @see org.millscript.commons.xml.api.token.TokenVisitor#visit(org.millscript.commons.xml.api.token.EmptyElementToken)
       */
      public void visit( final EmptyElementToken token ) {
          // this token is valid in this section
          this.wellFormed.nextToken = token;
      }
  
      /**
       * @see org.millscript.commons.xml.api.token.TokenVisitor#visit(org.millscript.commons.xml.api.token.EndTagToken)
       */
      public void visit( final EndTagToken token ) {
          // To be valid, this token must match the start tags
         if ( this.startTagToken.getName().equals( token.getName() ) ) {
             // this token is valid in this section
             this.wellFormed.nextToken = token;
             // but next time round we are in the "previous" visitor
             this.wellFormed.tokenVisitor = this.nextTokenVisitor;
             // reset the namespace scope to what it was just before this element
             // was read
             this.wellFormed.setNamespaces(
                 this.startTagToken.getPreviousNamespaceScope()
             );
         } else {
             throw new XmlWellFormednessAlert(
                 "Mismatched start/end tags"
             ).decorate( this.startTagToken ).decorate( token ).mishap();
         }
     }
 
     /**
      * @see org.millscript.commons.xml.api.token.TokenVisitor#visit(org.millscript.commons.xml.api.token.PIToken)
      */
     public void visit( final PIToken token ) {
         // this token is valid in this section
         this.wellFormed.nextToken = token;
     }
 
     /**
      * @see org.millscript.commons.xml.api.token.TokenVisitor#visit(org.millscript.commons.xml.api.token.StartTagToken)
      */
     public void visit( final StartTagToken token ) {
         // this token is valid in this section
         this.wellFormed.nextToken = token;
         // but we override the visitor for the next section
         // when we finish this content, we must return to this visitor
         this.wellFormed.tokenVisitor = new ContentTokenVisitor( this.wellFormed, this, token );
     }
 
 }