text: /*
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999-2001 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution,
   *    if any, must include the following acknowledgment:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowledgment may appear in the software itself,
   *    if and wherever such third-party acknowledgments normally appear.
   *
   * 4. The names "Xerces" and "Apache Software Foundation" must
   *    not be used to endorse or promote products derived from this
   *    software without prior written permission. For written
   *    permission, please contact apache\@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache",
   *    nor may "Apache" appear in their name, without prior written
   *    permission of the Apache Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation, and was
   * originally based on software copyright (c) 1999, International
   * Business Machines, Inc., http://www.ibm.com .  For more information
   * on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   */
  
  /*
   * $Log: SAX2XMLReader.hpp,v $
   * Revision 1.1  2004/07/13 02:37:42  WangKeBo
   * Component implementation
   *
   * Revision 1.1.1.1  2002/02/01 22:22:09  peiyongz
   * sane_include
   *
   * Revision 1.18  2002/01/28 18:45:40  knoaman
   * Update documentation for SAX2 feature 'namespace-prefixes'.
   *
   * Revision 1.17  2002/01/28 17:08:33  knoaman
   * SAX2-ext's DeclHandler support.
   *
   * Revision 1.16  2002/01/18 16:31:26  tng
   * Break program.xml which takes too long to load, into program-sax.xml, program-sax2.xml, program-dom.xml, program-idom.xml.
   *
   * Revision 1.15  2002/01/02 15:36:54  tng
   * Some documentation update.
   *
   * Revision 1.14  2001/11/20 18:51:44  tng
   * Schema: schemaLocation and noNamespaceSchemaLocation to be specified outside the instance document.  New methods setExternalSchemaLocation and setExternalNoNamespaceSchemaLocation are added (for SAX2, two new properties are added).
   *
   * Revision 1.13  2001/11/14 14:15:59  tng
   * Update SAX2 feature documentation.
   *
   * Revision 1.12  2001/09/12 13:03:43  tng
   * [Bug 3155] SAX2 does not offer progressive parse.
   *
   * Revision 1.11  2001/08/01 19:11:02  tng
   * Add full schema constraint checking flag to the samples and the parser.
   *
   * Revision 1.10  2001/06/27 17:40:16  knoaman
   * Fix for bug #2353.
   *
   * Revision 1.9  2001/06/19 16:44:31  tng
   * Add installAdvDocHandler to SAX2XMLReader as the code is there already.
   *
   * Revision 1.8  2001/06/04 21:03:07  jberry
   * Add pure virtual getErrorCount to SAX2XMLReader interface.
   *
   * Revision 1.7  2001/05/11 13:26:25  tng
   * Copyright update.
   *
   * Revision 1.6  2001/02/15 15:56:31  tng
   * Schema: Add setSchemaValidation and getSchemaValidation for DOMParser and SAXParser.
   * Add feature "http://apache.org/xml/features/validation/schema" for SAX2XMLReader.
   * New data field  fSchemaValidation in XMLScanner as the flag.
   *
   * Revision 1.5  2001/01/12 21:22:00  tng
   * Documentation Enhancement: Add list of SAX2 feature strings that are supported.
   *
   * Revision 1.4  2000/12/22 15:17:04  tng
   * SAX2-ext's LexicalHandler support added by David Bertoni.
   *
   * Revision 1.3  2000/08/09 22:19:29  jpolast
   * many conformance & stability changes:
   *   - ContentHandler::resetDocument() removed
   *   - attrs param of ContentHandler::startDocument() made const
   *   - SAXExceptions thrown now have msgs
   *   - removed duplicate function signatures that had 'const'
   *       [ eg: getContentHander() ]
   *   - changed getFeature and getProperty to apply to const objs
   *   - setProperty now takes a void* instead of const void*
   *   - SAX2XMLReaderImpl does not inherit from SAXParser anymore
   *   - Reuse Validator (http://apache.org/xml/features/reuse-validator) implemented
   *   - Features & Properties now read-only during parse
   *
   * Revision 1.2  2000/08/07 18:21:27  jpolast
   * change SAX_EXPORT module to SAX2_EXPORT
   *
   * Revision 1.1  2000/08/02 18:02:35  jpolast
   * initial checkin of sax2 implementation
   * submitted by Simon Fell (simon@fell.com)
   * and Joe Polastre (jpolast@apache.org)
   *
   *
   */
  
  #ifndef SAX2XMLReader_HPP
  #define SAX2XMLReader_HPP
  
  #include <xercesc/util/XercesDefs.hpp>
  #include <xercesc/util/XMLUniDefs.hpp>
  #include <xercesc/framework/XMLValidator.hpp>
  #include <xercesc/framework/XMLPScanToken.hpp>
  
  class ContentHandler ;
  class DTDHandler;
  class EntityResolver;
  class ErrorHandler;
  class InputSource;
  class LexicalHandler;
  class DeclHandler;
  class XMLDocumentHandler;
  
  class SAX2_EXPORT SAX2XMLReader
  {
  public:
  
      enum ValSchemes
      {
          Val_Never
          , Val_Always
          , Val_Auto
      };
  
      /** @name Constructors and Destructor */
      // -----------------------------------------------------------------------
      //  Constructors and Destructor
      // -----------------------------------------------------------------------
      //@{
      /** The default constructor */
      SAX2XMLReader()
      {
      }
      /** The destructor */
      virtual ~SAX2XMLReader()
      {
      }
      //@}
  
      //-----------------------------------------------------------------------
      // The XMLReader interface
      //-----------------------------------------------------------------------
      /** @name The XMLReader interfaces */
      //@{
  
      /** Get error count from the last parse operation.
        *
        * This method returns the error count from the last parse
        * operation. Note that this count is actually stored in the
        * scanner, so this method simply returns what the
        * scanner reports.
        *
        * @return number of errors encountered during the latest
        *			parse operation.
        */
      virtual int getErrorCount() const = 0 ;
  
      /**
        * This method returns the installed content handler.
        *
        * @return A pointer to the installed content handler object.
        */
      virtual ContentHandler* getContentHandler() const = 0 ;
  
      /**
        * This method returns the installed DTD handler.
        *
        * @return A pointer to the installed DTD handler object.
        */
      virtual DTDHandler* getDTDHandler() const = 0;
  
      /**
        * This method returns the installed entity resolver.
        *
        * @return A pointer to the installed entity resolver object.
        */
      virtual EntityResolver* getEntityResolver() const = 0 ;
  
      /**
        * This method returns the installed error handler.
        *
        * @return A pointer to the installed error handler object.
        */
      virtual ErrorHandler* getErrorHandler() const = 0 ;
  
  	/**
        * This method returns the installed lexical handler.
        *
        * @return A pointer to the installed lexical handler object.
        */
      virtual LexicalHandler* getLexicalHandler() const = 0 ;
  
      /**
        * This method returns the installed declaration handler.
        *
        * @return A pointer to the installed declaration handler object.
        */
      virtual DeclHandler* getDeclarationHandler() const = 0 ;
  
  	/**
       * Query the current state of any feature in a SAX2 XMLReader.
  	  *
  	  * @param name The unique identifier (URI) of the feature being set.
  	  * @return The current state of the feature.
       * @exception SAXNotRecognizedException If the requested feature is not known.
  	  */
  	virtual bool getFeature(const XMLCh* const name) const = 0;
  
  	/**
       * Query the current value of a property in a SAX2 XMLReader.
       *
       * The parser owns the returned pointer.  The memory allocated for
       * the returned pointer will be destroyed when the parser is deleted.
       *
       * To ensure assessiblity of the returned information after the parser
       * is deleted, callers need to copy and store the returned information
       * somewhere else; otherwise you may get unexpected result.  Since the returned
       * pointer is a generic void pointer, see
       * http://xml.apache.org/xerces-c/program-sax2.html#SAX2Properties to learn
       * exactly what type of property value each property returns for replication.
       *
       * @param name The unique identifier (URI) of the property being set.
       * @return     The current value of the property.  The pointer spans the same
       *             life-time as the parser.  A null pointer is returned if nothing
       *             was specified externally.
       * @exception  SAXNotRecognizedException If the requested property is not known.
       */
  	virtual void* getProperty(const XMLCh* const name) const = 0 ;
  
      /**
        * This method returns the state of the parser's
        * exit-on-First-Fatal-Error flag.
        *
        * @return true, if the parser is currently configured to
        *         exit on the first fatal error, false otherwise.
        *
        * @see #setExitOnFirstFatalError
        */
      virtual bool getExitOnFirstFatalError() const = 0;
  
      /**
        * This method returns the state of the parser's
        * validation-constraint-fatal flag.
        *
        * @return true, if the parser is currently configured to
        *         set validation constraint errors as fatal, false
        *         otherwise.
        *
        * @see #setValidationContraintFatal
        */
      virtual bool getValidationConstraintFatal() const = 0;
  
  
    /**
      * Parse an XML document.
      *
      * The application can use this method to instruct the SAX parser
      * to begin parsing an XML document from any valid input
      * source (a character stream, a byte stream, or a URI).
      *
      * Applications may not invoke this method while a parse is in
      * progress (they should create a new Parser instead for each
      * additional XML document).  Once a parse is complete, an
      * application may reuse the same Parser object, possibly with a
      * different input source.
      *
      * @param source The input source for the top-level of the
      *               XML document.
      * @exception SAXException Any SAX exception, possibly
      *            wrapping another exception.
      * @exception XMLException An exception from the parser or client
      *            handler code.
      * @see InputSource#InputSource
      * @see #setEntityResolver
      * @see #setDTDHandler
      * @see #setDocumentHandler
      * @see #setErrorHandler
      */
      virtual void parse
      (
          const   InputSource&    source
      ) = 0;
  
    /**
      * Parse an XML document from a system identifier (URI).
      *
      * This method is a shortcut for the common case of reading a
      * document from a system identifier.  It is the exact equivalent
      * of the following:
      *
      * parse(new URLInputSource(systemId));
      *
      * If the system identifier is a URL, it must be fully resolved
      * by the application before it is passed to the parser.
      *
      * @param systemId The system identifier (URI).
      * @exception SAXException Any SAX exception, possibly
      *            wrapping another exception.
      * @exception XMLException An exception from the parser or client
      *            handler code.
      * @see #parse(InputSource)
      */
      virtual void parse
      (
          const   XMLCh* const    systemId
      ) = 0;
  
    /**
      * Parse an XML document from a system identifier (URI).
      *
      * This method is a shortcut for the common case of reading a
      * document from a system identifier.  It is the exact equivalent
      * of the following:
      *
      * parse(new URLInputSource(systemId));
      *
      * If the system identifier is a URL, it must be fully resolved
      * by the application before it is passed to the parser.
      *
      * @param systemId The system identifier (URI).
      * @exception SAXException Any SAX exception, possibly
      *            wrapping another exception.
      * @exception XMLException An exception from the parser or client
      *            handler code.
      * @see #parse(InputSource)
      */
      virtual void parse
      (
          const   char* const     systemId
      ) = 0;
  	
    /**
      * Allow an application to register a document event handler.
      *
      * If the application does not register a document handler, all
      * document events reported by the SAX parser will be silently
      * ignored (this is the default behaviour implemented by
      * HandlerBase).
      *
      * Applications may register a new or different handler in the
      * middle of a parse, and the SAX parser must begin using the new
      * handler immediately.
      *
      * @param handler The document handler.
      * @see DocumentHandler#DocumentHandler
      * @see HandlerBase#HandlerBase
      */
      virtual void setContentHandler(ContentHandler* const handler) = 0;
  
    /**
      * Allow an application to register a DTD event handler.
      *
      * If the application does not register a DTD handler, all DTD
      * events reported by the SAX parser will be silently ignored (this
      * is the default behaviour implemented by HandlerBase).
      *
      * Applications may register a new or different handler in the middle
      * of a parse, and the SAX parser must begin using the new handler
      * immediately.
      *
      * @param handler The DTD handler.
      * @see DTDHandler#DTDHandler
      * @see HandlerBase#HandlerBase
      */
      virtual void setDTDHandler(DTDHandler* const handler) = 0;
  
    /**
      * Allow an application to register a custom entity resolver.
      *
      * If the application does not register an entity resolver, the
      * SAX parser will resolve system identifiers and open connections
      * to entities itself (this is the default behaviour implemented in
      * DefaultHandler).
      *
      * Applications may register a new or different entity resolver
      * in the middle of a parse, and the SAX parser must begin using
      * the new resolver immediately.
      *
      * @param resolver The object for resolving entities.
      * @see EntityResolver#EntityResolver
      * @see DefaultHandler#DefaultHandler
      */
      virtual void setEntityResolver(EntityResolver* const resolver) = 0;
  
    /**
      * Allow an application to register an error event handler.
      *
      * If the application does not register an error event handler,
      * all error events reported by the SAX parser will be silently
      * ignored, except for fatalError, which will throw a SAXException
      * (this is the default behaviour implemented by HandlerBase).
      *
      * Applications may register a new or different handler in the
      * middle of a parse, and the SAX parser must begin using the new
      * handler immediately.
      *
      * @param handler The error handler.
      * @see ErrorHandler#ErrorHandler
      * @see SAXException#SAXException
      * @see HandlerBase#HandlerBase
      */
      virtual void setErrorHandler(ErrorHandler* const handler) = 0;
  
     /**
      * Allow an application to register a lexical event handler.
      *
      * If the application does not register a lexical handler,
      * all events reported by the SAX parser will be silently
      * ignored. (this is the default behaviour implemented by HandlerBase).
      *
      * Applications may register a new or different handler in the
      * middle of a parse, and the SAX parser must begin using the new
      * handler immediately.
      *
      * @param handler The error handler.
      * @see LexicalHandler#LexicalHandler
      * @see SAXException#SAXException
      * @see HandlerBase#HandlerBase
      */
      virtual void setLexicalHandler(LexicalHandler* const handler) = 0;
  
     /**
      * Allow an application to register a declaration event handler.
      *
      * If the application does not register a declaration handler,
      * all events reported by the SAX parser will be silently
      * ignored. (this is the default behaviour implemented by DefaultHandler).
      *
      * Applications may register a new or different handler in the
      * middle of a parse, and the SAX parser must begin using the new
      * handler immediately.
      *
      * @param handler The DTD declaration handler.
      * @see DeclHandler#DeclHandler
      * @see SAXException#SAXException
      * @see DefaultHandler#DefaultHandler
      */
      virtual void setDeclarationHandler(DeclHandler* const handler) = 0;
  
      /**
        * This method allows users to set the parser's behaviour when it
        * encounters the first fatal error. If set to true, the parser
        * will exit at the first fatal error. If false, then it will
        * report the error and continue processing.
        *
        * <p>The default value is 'true' and the parser exits on the
        * first fatal error.</p>
        *
        * @param newState The value specifying whether the parser should
        *                 continue or exit when it encounters the first
        *                 fatal error.
        *
        * @see #getExitOnFirstFatalError
        */
      virtual void setExitOnFirstFatalError(const bool newState) = 0;
  
      /**
        * This method allows users to set the parser's behaviour when it
        * encounters a validtion constraint error. If set to true, and the
        * the parser is set to exit when it encounter the first fatal error,
        * the parser will exit at the first encounter. If false, then it will
        * report the error and continue processing.
        *
        * <p>The default value is 'false'.</p>
        *
        * @param newState The value specifying whether the parser should
        *                 continue or exit when it encounters a validation
        *                 constraint error.
        *
        * @see #getValidationConstraintFatal
        */
      virtual void setValidationConstraintFatal(const bool newState) = 0;
  
    /**
      * Set the state of any feature in a SAX2 XMLReader.
      * Supported features in SAX2 for xerces-c are:
      * <br>(See http://xml.apache.org/xerces-c/program-sax2.html#SAX2Features for detail description).
      *
      * <br>http://xml.org/sax/features/validation (default: true)
      * <br>http://xml.org/sax/features/namespaces (default: true)
      * <br>http://xml.org/sax/features/namespace-prefixes (default: false)
      * <br>http://apache.org/xml/features/validation/dynamic (default: false)
      * <br>http://apache.org/xml/features/validation/reuse-grammar (default: false)
      * <br>http://apache.org/xml/features/validation/schema (default: true)
      * <br>http://apache.org/xml/features/validation/schema-full-checking (default: false)
      * <br>http://apache.org/xml/features/validation/reuse-validator (Deprecated) (default: false)
      *
      * @param name The unique identifier (URI) of the feature.
      * @param value The requested state of the feature (true or false).
      * @exception SAXNotRecognizedException If the requested feature is not known.
      * @exception SAXNotSupportedException Feature modification is not supported during parse
      *
      */
  	virtual void setFeature(const XMLCh* const name, const bool value) = 0;
  
    /**
      * Set the value of any property in a SAX2 XMLReader.
      * Supported properties in SAX2 for xerces-c are:
      * <br>(See http://xml.apache.org/xerces-c/program-sax2.html#SAX2Properties for detail description).
      *
      * <br>http://apache.org/xml/properties/schema/external-schemaLocation
      * <br>http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation.
      *
      * It takes a void pointer as the property value.  Application is required to initialize this void
      * pointer to a correct type.  See http://xml.apache.org/xerces-c/program-sax2.html#SAX2Properties
      * to learn exactly what type of property value each property expects for processing.
      * Passing a void pointer that was initialized with a wrong type will lead to unexpected result.
      * If the same property is set more than once, the last one takes effect.
      *
      * @param name The unique identifier (URI) of the property being set.
      * @param value The requested value for the property.  See
      *            http://xml.apache.org/xerces-c/program-sax2.html#SAX2Properties to learn
      *            exactly what type of property value each property expects for processing.
      *            Passing a void pointer that was initialized with a wrong type will lead
      *            to unexpected result.
      * @exception SAXNotRecognizedException If the requested property is not known.
      * @exception SAXNotSupportedException Property modification is not supported during parse
      */
  	virtual void setProperty(const XMLCh* const name, void* value) = 0 ;
  
      //@}
  
      // -----------------------------------------------------------------------
      //  Progressive scan methods
      // -----------------------------------------------------------------------
  
      /** @name Progressive scan methods */
      //@{
  
      /** Begin a progressive parse operation
        *
        * This method is used to start a progressive parse on a XML file.
        * To continue parsing, subsequent calls must be to the parseNext
        * method.
        *
        * It scans through the prolog and returns a token to be used on
        * subsequent scanNext() calls. If the return value is true, then the
        * token is legal and ready for further use. If it returns false, then
        * the scan of the prolog failed and the token is not going to work on
        * subsequent scanNext() calls.
        *
        * @param systemId A pointer to a Unicode string represting the path
        *                 to the XML file to be parsed.
        * @param toFill   A token maintaing state information to maintain
        *                 internal consistency between invocation of 'parseNext'
        *                 calls.
        * @param reuseGrammar The flag indicating whether the existing Grammar
        *                     should be reused or not for this parsing run.
        *                     If true, there cannot be any internal subset.
        *
        * @return 'true', if successful in parsing the prolog. It indicates the
        *         user can go ahead with parsing the rest of the file. It
        *         returns 'false' to indicate that the parser could parse the
        *         prolog (which means the token will not be valid.)
        *
        * @see #parseNext
        * @see #parseFirst(char*,...)
        * @see #parseFirst(InputSource&,...)
        */
      virtual bool parseFirst
      (
          const   XMLCh* const    systemId
          ,       XMLPScanToken&  toFill
          , const bool            reuseGrammar = false
      ) = 0;
  
      /** Begin a progressive parse operation
        *
        * This method is used to start a progressive parse on a XML file.
        * To continue parsing, subsequent calls must be to the parseNext
        * method.
        *
        * It scans through the prolog and returns a token to be used on
        * subsequent scanNext() calls. If the return value is true, then the
        * token is legal and ready for further use. If it returns false, then
        * the scan of the prolog failed and the token is not going to work on
        * subsequent scanNext() calls.
        *
        * @param systemId A pointer to a regular native string represting
        *                 the path to the XML file to be parsed.
        * @param toFill   A token maintaing state information to maintain
        *                 internal consIstency between invocation of 'parseNext'
        *                 calls.
        * @param reuseGrammar The flag indicating whether the existing Grammar
        *                     should be reused or not for this parsing run.
        *                     If true, there cannot be any internal subset.
        *
        * @return 'true', if successful in parsing the prolog. It indicates the
        *         user can go ahead with parsing the rest of the file. It
        *         returns 'false' to indicate that the parser could not parse
        *         the prolog.
        *
        * @see #parseNext
        * @see #parseFirst(XMLCh*,...)
        * @see #parseFirst(InputSource&,...)
        */
      virtual bool parseFirst
      (
          const   char* const     systemId
          ,       XMLPScanToken&  toFill
          , const bool            reuseGrammar = false
      ) = 0;
  
      /** Begin a progressive parse operation
        *
        * This method is used to start a progressive parse on a XML file.
        * To continue parsing, subsequent calls must be to the parseNext
        * method.
        *
        * It scans through the prolog and returns a token to be used on
        * subsequent scanNext() calls. If the return value is true, then the
        * token is legal and ready for further use. If it returns false, then
        * the scan of the prolog failed and the token is not going to work on
        * subsequent scanNext() calls.
        *
        * @param source   A const reference to the InputSource object which
        *                 points to the XML file to be parsed.
        * @param toFill   A token maintaing state information to maintain
        *                 internal consistency between invocation of 'parseNext'
        *                 calls.
        * @param reuseGrammar The flag indicating whether the existing Grammar
        *                     should be reused or not for this parsing run.
        *                     If true, there cannot be any internal subset.
        *
        * @return 'true', if successful in parsing the prolog. It indicates the
        *         user can go ahead with parsing the rest of the file. It
        *         returns 'false' to indicate that the parser could not parse
        *         the prolog.
        *
        * @see #parseNext
        * @see #parseFirst(XMLCh*,...)
        * @see #parseFirst(char*,...)
        */
      virtual bool parseFirst
      (
          const   InputSource&    source
          ,       XMLPScanToken&  toFill
          , const bool            reuseGrammar = false
      ) = 0;
  
      /** Continue a progressive parse operation
        *
        * This method is used to continue with progressive parsing of
        * XML files started by a call to 'parseFirst' method.
        *
        * It parses the XML file and stops as soon as it comes across
        * a XML token (as defined in the XML specification). Relevant
        * callback handlers are invoked as required by the SAX
        * specification.
        *
        * @param token A token maintaing state information to maintain
        *              internal consistency between invocation of 'parseNext'
        *              calls.
        *
        * @return 'true', if successful in parsing the next XML token.
        *         It indicates the user can go ahead with parsing the rest
        *         of the file. It returns 'false' to indicate that the parser
        *         could not find next token as per the XML specification
        *         production rule.
        *
        * @see #parseFirst(XMLCh*,...)
        * @see #parseFirst(char*,...)
        * @see #parseFirst(InputSource&,...)
        */
      virtual bool parseNext(XMLPScanToken& token) = 0;
  
      /** Reset the parser after a progressive parse
        *
        * If a progressive parse loop exits before the end of the document
        * is reached, the parser has no way of knowing this. So it will leave
        * open any files or sockets or memory buffers that were in use at
        * the time that the parse loop exited.
        *
        * The next parse operation will cause these open files and such to
        * be closed, but the next parse operation might occur at some unknown
        * future point. To avoid this problem, you should reset the parser if
        * you exit the loop early.
        *
        * If you exited because of an error, then this cleanup will be done
        * for you. Its only when you exit the file prematurely of your own
        * accord, because you've found what you wanted in the file most
        * likely.
        *
        * @param token A token maintaing state information to maintain
        *              internal consistency between invocation of 'parseNext'
        *              calls.
        */
      virtual void parseReset(XMLPScanToken& token) = 0;
  
      //@}
  
  
      // -----------------------------------------------------------------------
      //  Validator: setters and getters
      // -----------------------------------------------------------------------
      /** @name Validator: setters and getters (Xerces-C specific) */
      //@{
      /**
  	  * This method is used to set a validator.
  	  *
  	  * <b>SAX2XMLReader assumes responsibility for the validator.  It will be
  	  * deleted when the XMLReader is destroyed.</b>
  	  *
  	  * @param valueToAdopt A pointer to the validator that the reader should use.
  	  *
  	  */
  	virtual void setValidator(XMLValidator* valueToAdopt) = 0;
  
      /**
  	  * This method is used to get the current validator.
  	  *
  	  * <b>SAX2XMLReader assumes responsibility for the validator.  It will be
  	  * deleted when the XMLReader is destroyed.</b>
  	  *
  	  * @return A pointer to the validator.  An application should not deleted
  	  * the object returned.
  	  *
  	  */
  	virtual XMLValidator* getValidator() const = 0;
      //@}
  
      // -----------------------------------------------------------------------
      //  Advanced document handler list maintenance methods
      // -----------------------------------------------------------------------
  
      /** @name Advanced document handler list maintenance methods */
      //@{
      /**
        * This method installs the specified 'advanced' document callback
        * handler, thereby allowing the user to customize the processing,
        * if they choose to do so. Any number of advanced callback handlers
        * maybe installed.
        *
        * <p>The methods in the advanced callback interface represent
        * Xerces-C extensions. There is no specification for this interface.</p>
        *
        * @param toInstall A pointer to the users advanced callback handler.
        *
        * @see #removeAdvDocHandler
        */
      virtual void installAdvDocHandler(XMLDocumentHandler* const toInstall) = 0;
  
      /**
        * This method removes the 'advanced' document handler callback from
        * the underlying parser scanner. If no handler is installed, advanced
        * callbacks are not invoked by the scanner.
        * @param toRemove A pointer to the advanced callback handler which
        *                 should be removed.
        *
        * @see #installAdvDocHandler
        */
      virtual bool removeAdvDocHandler(XMLDocumentHandler* const toRemove) = 0;
      //@}
  
  private :
      /* The copy constructor, you cannot call this directly */
      SAX2XMLReader(const SAX2XMLReader&);
  
      /* The assignment operator, you cannot call this directly */
      void operator=(const SAX2XMLReader&);
  
  };
  
  #endif
  