/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 * 

 *      http://www.apache.org/licenses/LICENSE-2.0

 * 

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

/*

 * $Id: ContentHandler.hpp 568078 2007-08-21 11:43:25Z amassari $

 */

#ifndef CONTENTHANDLER_HPP

#define CONTENTHANDLER_HPP

#include <xercesc/util/XercesDefs.hpp>

XERCES_CPP_NAMESPACE_BEGIN

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 */

    ContentHandler& operator=(const ContentHandler&);

};

XERCES_CPP_NAMESPACE_END

#endif