/*
 * The Apache Software License, Version 1.1
 * 
 * Copyright (c) 1999-2000 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: ContentHandler.hpp,v $
 * 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 18:02:34  jpolast
 * initial checkin of sax2 implementation
 * submitted by Simon Fell (simon@fell.com)
 * and Joe Polastre (jpolast@apache.org)
 *
 *
 */


#ifndef CONTENTHANDLER_HPP
#define CONTENTHANDLER_HPP

#include <util/XercesDefs.hpp>

class Attributes;
class Locator;

/**
  * Receive notification of general document events.
  *
  * <p>This is the main interface that most SAX2 applications
  * implement: if the application needs to be informed of basic parsing 
  * events, it implements this interface and registers an instance with 
  * the SAX2 parser using the setDocumentHandler method.  The parser 
  * uses the instance to report basic document-related events like
  * the start and end of elements and character data.</p>
  *
  * <p>The order of events in this interface is very important, and
  * mirrors the order of information in the document itself.  For
  * example, all of an element's content (character data, processing
  * instructions, and/or subelements) will appear, in order, between
  * the startElement event and the corresponding endElement event.</p>
  *
  * <p>Application writers who do not want to implement the entire
  * interface while can derive a class from Sax2HandlerBase, which implements
  * the default functionality; parser writers can instantiate
  * Sax2HandlerBase to obtain a default handler.  The application can find
  * the location of any document event using the Locator interface
  * supplied by the Parser through the setDocumentLocator method.</p>
  *
  * @see Parser#setDocumentHandler
  * @see Locator#Locator
  * @see Sax2HandlerBase#Sax2HandlerBase
  */

class SAX2_EXPORT ContentHandler
{
public:
    /** @name Constructors and Destructor */
    //@{
    /** Default constructor */
    ContentHandler()
    {
    }

    /** Destructor */
    virtual ~ContentHandler()
    {
    }
    //@}

    /** @name The virtual document handler interface */
    
    //@{
   /**
    * Receive notification of character data.
    *
    * <p>The Parser will call this method to report each chunk of
    * character data.  SAX parsers may return all contiguous character
    * data in a single chunk, or they may split it into several
    * chunks; however, all of the characters in any single event
    * must come from the same external entity, so that the Locator
    * provides useful information.</p>
    *
    * <p>The application must not attempt to read from the array
    * outside of the specified range.</p>
    *
    * <p>Note that some parsers will report whitespace using the
    * ignorableWhitespace() method rather than this one (validating
    * parsers must do so).</p>
    *
    * @param chars The characters from the XML document.
    * @param length The number of characters to read from the array.
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    * @see #ignorableWhitespace 
    * @see Locator#Locator
    */
    virtual void characters
    (
        const   XMLCh* const    chars
        , const unsigned int    length
    ) = 0;

  /**
    * Receive notification of the end of a document.
    *
    * <p>The SAX parser will invoke this method only once, and it will
    * be the last method invoked during the parse.  The parser shall
    * not invoke this method until it has either abandoned parsing
    * (because of an unrecoverable error) or reached the end of
    * input.</p>
    *
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    */
    virtual void endDocument () = 0;

  /**
    * Receive notification of the end of an element.
    *
    * <p>The SAX parser will invoke this method at the end of every
    * element in the XML document; there will be a corresponding
    * startElement() event for every endElement() event (even when the
    * element is empty).</p>
    *
    * @param uri The URI of the asscioated namespace for this element
	* @param localname The local part of the element name
	* @param qname The QName of this element
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    */
    virtual void endElement
	(
		const XMLCh* const uri, 
		const XMLCh* const localname, 
		const XMLCh* const qname
	) = 0;

  /**
    * Receive notification of ignorable whitespace in element content.
    *
    * <p>Validating Parsers must use this method to report each chunk
    * of ignorable whitespace (see the W3C XML 1.0 recommendation,
    * section 2.10): non-validating parsers may also use this method
    * if they are capable of parsing and using content models.</p>
    *
    * <p>SAX parsers may return all contiguous whitespace in a single
    * chunk, or they may split it into several chunks; however, all of
    * the characters in any single event must come from the same
    * external entity, so that the Locator provides useful
    * information.</p>
    *
    * <p>The application must not attempt to read from the array
    * outside of the specified range.</p>
    *
    * @param chars The characters from the XML document.
    * @param length The number of characters to read from the array.
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    * @see #characters
    */
    virtual void ignorableWhitespace
    (
        const   XMLCh* const    chars
        , const unsigned int    length
    ) = 0;

  /**
    * Receive notification of a processing instruction.
    *
    * <p>The Parser will invoke this method once for each processing
    * instruction found: note that processing instructions may occur
    * before or after the main document element.</p>
    *
    * <p>A SAX parser should never report an XML declaration (XML 1.0,
    * section 2.8) or a text declaration (XML 1.0, section 4.3.1)
    * using this method.</p>
    *
    * @param target The processing instruction target.
    * @param data The processing instruction data, or null if
    *        none was supplied.
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    */
    virtual void processingInstruction
    (
        const   XMLCh* const    target
        , const XMLCh* const    data
    ) = 0;

  /**
    * Receive an object for locating the origin of SAX document events.
    *
    * SAX parsers are strongly encouraged (though not absolutely
    * required) to supply a locator: if it does so, it must supply
    * the locator to the application by invoking this method before
    * invoking any of the other methods in the DocumentHandler
    * interface.
    *
    * The locator allows the application to determine the end
    * position of any document-related event, even if the parser is
    * not reporting an error.  Typically, the application will
    * use this information for reporting its own errors (such as
    * character content that does not match an application's
    * business rules). The information returned by the locator
    * is probably not sufficient for use with a search engine.
    *
    * Note that the locator will return correct information only
    * during the invocation of the events in this interface. The
    * application should not attempt to use it at any other time.
    *
    * @param locator An object that can return the location of
    *                any SAX document event. The object is only
    *                'on loan' to the client code and they are not
    *                to attempt to delete or modify it in any way!
    *
    * @see Locator#Locator
    */
    virtual void setDocumentLocator(const Locator* const locator) = 0;

  /**
    * Receive notification of the beginning of a document.
    *
    * <p>The SAX parser will invoke this method only once, before any
    * other methods in this interface or in DTDHandler (except for
    * setDocumentLocator).</p>
    *
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    */
    virtual void startDocument() = 0;

  /**
    * Receive notification of the beginning of an element.
    *
    * <p>The Parser will invoke this method at the beginning of every
    * element in the XML document; there will be a corresponding
    * endElement() event for every startElement() event (even when the
    * element is empty). All of the element's content will be
    * reported, in order, before the corresponding endElement()
    * event.</p>
    *
    * <p>Note that the attribute list provided will
    * contain only attributes with explicit values (specified or
    * defaulted): #IMPLIED attributes will be omitted.</p>
    *
    * @param uri The URI of the asscioated namespace for this element
	* @param localname The local part of the element name
	* @param qname The QName of this element
    * @param attrs The attributes attached to the element, if any.
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    * @see #endElement
    * @see Attributes#Attributes
    */
    virtual void startElement
    (
        const   XMLCh* const    uri,
        const   XMLCh* const    localname,
        const   XMLCh* const    qname,
        const   Attributes&     attrs
    ) = 0;

  /**
    * Receive notification of the start of an namespace prefix mapping.
    *
    * <p>By default, do nothing.  Application writers may override this
    * method in a subclass to take specific actions at the start of
    * each namespace prefix mapping.</p>
    *
    * @param prefix The namespace prefix used
    * @param uri The namespace URI used.
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    */
	virtual void startPrefixMapping
	( 
		const	XMLCh* const	prefix,
		const	XMLCh* const	uri
	) = 0 ;

  /**
    * Receive notification of the end of an namespace prefix mapping.
    *
    * <p>By default, do nothing.  Application writers may override this
    * method in a subclass to take specific actions at the end of
    * each namespace prefix mapping.</p>
    *
    * @param prefix The namespace prefix used
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    */
	virtual void endPrefixMapping
	(
		const	XMLCh* const	prefix
	) = 0 ;

    //@}

  /**
    * Receive notification of a skipped entity
    *
    * <p>The parser will invoke this method once for each entity
	* skipped.  All processors may skip external entities,
	* depending on the values of the features:<br>
	* http://xml.org/sax/features/external-general-entities<br>
	* http://xml.org/sax/features/external-parameter-entities</p>
	*
	* <p>Note: Xerces (specifically) never skips any entities, regardless
	* of the above features.  This function is never called in the
	* Xerces implementation of SAX2.</p>
    *
	* <p>Introduced with SAX2</p>
	*
    * @param name The name of the skipped entity.  If it is a parameter entity, 
	* the name will begin with %, and if it is the external DTD subset, 
	* it will be the string [dtd].
    * @exception SAXException Any SAX exception, possibly
    *            wrapping another exception.
    */
	virtual void skippedEntity
	(
		const	XMLCh* const	name
	) = 0 ;

    //@}
private :
    /* Unimplemented Constructors and operators */
    /* Copy constructor */
    ContentHandler(const ContentHandler&);
    /** Assignment operator */
    void operator=(const ContentHandler&);
};

#endif
