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// LexicalHandler.java - optional handler for lexical parse events.
// http://www.saxproject.org
// Public Domain: no warranty.
// $Id: LexicalHandler.java,v 1.2 2004/11/03 22:49:08 jsuttor Exp $

package org.xml.sax.ext;

import org.xml.sax.SAXException;

SAX2 extension handler for lexical events.

This module, both source code and documentation, is in the
Public Domain, and comes with NO WARRANTY.
See http://www.saxproject.org
for further information.

This is an optional extension handler for SAX2 to provide
lexical information about an XML document, such as comments
and CDATA section boundaries.
XML readers are not required to recognize this handler, and it
is not part of core-only SAX2 distributions.
The events in the lexical handler apply to the entire document,
not just to the document element, and all lexical handler events
must appear between the content handler's startDocument and
endDocument events.
To set the LexicalHandler for an XML reader, use the setProperty method with the property name http://xml.org/sax/properties/lexical-handler and an object implementing this interface (or null) as the value. If the reader does not report lexical events, it will throw a SAXNotRecognizedException when you attempt to register the handler.
Author:
David Megginson
Since:
1.4, SAX 2.0 (extensions 1.0)/**
 * SAX2 extension handler for lexical events.
 *
 * <blockquote>
 * <em>This module, both source code and documentation, is in the
 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
 * for further information.
 * </blockquote>
 *
 * <p>This is an optional extension handler for SAX2 to provide
 * lexical information about an XML document, such as comments
 * and CDATA section boundaries.
 * XML readers are not required to recognize this handler, and it
 * is not part of core-only SAX2 distributions.</p>
 *
 * <p>The events in the lexical handler apply to the entire document,
 * not just to the document element, and all lexical handler events
 * must appear between the content handler's startDocument and
 * endDocument events.</p>
 *
 * <p>To set the LexicalHandler for an XML reader, use the
 * {@link org.xml.sax.XMLReader#setProperty setProperty} method
 * with the property name
 * <code>http://xml.org/sax/properties/lexical-handler</code>
 * and an object implementing this interface (or null) as the value.
 * If the reader does not report lexical events, it will throw a
 * {@link org.xml.sax.SAXNotRecognizedException SAXNotRecognizedException}
 * when you attempt to register the handler.</p>
 *
 * @since 1.4, SAX 2.0 (extensions 1.0)
 * @author David Megginson
 */
public interface LexicalHandler
{

    
Report the start of DTD declarations, if any.
This method is intended to report the beginning of the
DOCTYPE declaration; if the document has no DOCTYPE declaration,
this method will not be invoked.
All declarations reported through DTDHandler or DeclHandler events must appear between the startDTD and endDTD events. Declarations are assumed to belong to the internal DTD subset unless they appear between startEntity and endEntity events. Comments and processing instructions from the DTD should also be reported between the startDTD and endDTD events, in their original order of (logical) occurrence; they are not required to appear in their correct locations relative to DTDHandler or DeclHandler events, however.
Note that the start/endDTD events will appear within the start/endDocument events from ContentHandler and before the first startElement event.
Params:
name – The document type name.
publicId – The declared public identifier for the
       external DTD subset, or null if none was declared.
systemId – The declared system identifier for the
       external DTD subset, or null if none was declared.
       (Note that this is not resolved against the document
       base URI.)
Throws:
SAXException – The application may raise an
           exception.
See Also:
endDTD
startEntity/**
     * Report the start of DTD declarations, if any.
     *
     * <p>This method is intended to report the beginning of the
     * DOCTYPE declaration; if the document has no DOCTYPE declaration,
     * this method will not be invoked.</p>
     *
     * <p>All declarations reported through
     * {@link org.xml.sax.DTDHandler DTDHandler} or
     * {@link org.xml.sax.ext.DeclHandler DeclHandler} events must appear
     * between the startDTD and {@link #endDTD endDTD} events.
     * Declarations are assumed to belong to the internal DTD subset
     * unless they appear between {@link #startEntity startEntity}
     * and {@link #endEntity endEntity} events.  Comments and
     * processing instructions from the DTD should also be reported
     * between the startDTD and endDTD events, in their original
     * order of (logical) occurrence; they are not required to
     * appear in their correct locations relative to DTDHandler
     * or DeclHandler events, however.</p>
     *
     * <p>Note that the start/endDTD events will appear within
     * the start/endDocument events from ContentHandler and
     * before the first
     * {@link org.xml.sax.ContentHandler#startElement startElement}
     * event.</p>
     *
     * @param name The document type name.
     * @param publicId The declared public identifier for the
     *        external DTD subset, or null if none was declared.
     * @param systemId The declared system identifier for the
     *        external DTD subset, or null if none was declared.
     *        (Note that this is not resolved against the document
     *        base URI.)
     * @exception SAXException The application may raise an
     *            exception.
     * @see #endDTD
     * @see #startEntity
     */
    public abstract void startDTD (String name, String publicId,
                                   String systemId)
        throws SAXException;


    
Report the end of DTD declarations.
This method is intended to report the end of the
DOCTYPE declaration; if the document has no DOCTYPE declaration,
this method will not be invoked.
Throws:
SAXException – The application may raise an exception.
See Also:
startDTD/**
     * Report the end of DTD declarations.
     *
     * <p>This method is intended to report the end of the
     * DOCTYPE declaration; if the document has no DOCTYPE declaration,
     * this method will not be invoked.</p>
     *
     * @exception SAXException The application may raise an exception.
     * @see #startDTD
     */
    public abstract void endDTD ()
        throws SAXException;


    
Report the beginning of some internal and external XML entities.
The reporting of parameter entities (including
the external DTD subset) is optional, and SAX2 drivers that
report LexicalHandler events may not implement it; you can use the
http://xml.org/sax/features/lexical-handler/parameter-entities
feature to query or control the reporting of parameter entities.
General entities are reported with their regular names,
parameter entities have '%' prepended to their names, and
the external DTD subset has the pseudo-entity name "[dtd]".
When a SAX2 driver is providing these events, all other events must be properly nested within start/end entity events. There is no additional requirement that events from DeclHandler or DTDHandler be properly ordered.
Note that skipped entities will be reported through the skippedEntity event, which is part of the ContentHandler interface.
Because of the streaming event model that SAX uses, some
entity boundaries cannot be reported under any
circumstances:

general entities within attribute values
parameter entities within declarations

These will be silently expanded, with no indication of where
the original entity boundaries were.
Note also that the boundaries of character references (which
are not really entities anyway) are not reported.
All start/endEntity events must be properly nested.
Params:
name – The name of the entity.  If it is a parameter
       entity, the name will begin with '%', and if it is the
       external DTD subset, it will be "[dtd]".
Throws:
SAXException – The application may raise an exception.
See Also:
endEntity
DeclHandler.internalEntityDecl
DeclHandler.externalEntityDecl/**
     * Report the beginning of some internal and external XML entities.
     *
     * <p>The reporting of parameter entities (including
     * the external DTD subset) is optional, and SAX2 drivers that
     * report LexicalHandler events may not implement it; you can use the
     * <code
     * >http://xml.org/sax/features/lexical-handler/parameter-entities</code>
     * feature to query or control the reporting of parameter entities.</p>
     *
     * <p>General entities are reported with their regular names,
     * parameter entities have '%' prepended to their names, and
     * the external DTD subset has the pseudo-entity name "[dtd]".</p>
     *
     * <p>When a SAX2 driver is providing these events, all other
     * events must be properly nested within start/end entity
     * events.  There is no additional requirement that events from
     * {@link org.xml.sax.ext.DeclHandler DeclHandler} or
     * {@link org.xml.sax.DTDHandler DTDHandler} be properly ordered.</p>
     *
     * <p>Note that skipped entities will be reported through the
     * {@link org.xml.sax.ContentHandler#skippedEntity skippedEntity}
     * event, which is part of the ContentHandler interface.</p>
     *
     * <p>Because of the streaming event model that SAX uses, some
     * entity boundaries cannot be reported under any
     * circumstances:</p>
     *
     * <ul>
     * <li>general entities within attribute values</li>
     * <li>parameter entities within declarations</li>
     * </ul>
     *
     * <p>These will be silently expanded, with no indication of where
     * the original entity boundaries were.</p>
     *
     * <p>Note also that the boundaries of character references (which
     * are not really entities anyway) are not reported.</p>
     *
     * <p>All start/endEntity events must be properly nested.
     *
     * @param name The name of the entity.  If it is a parameter
     *        entity, the name will begin with '%', and if it is the
     *        external DTD subset, it will be "[dtd]".
     * @exception SAXException The application may raise an exception.
     * @see #endEntity
     * @see org.xml.sax.ext.DeclHandler#internalEntityDecl
     * @see org.xml.sax.ext.DeclHandler#externalEntityDecl
     */
    public abstract void startEntity (String name)
        throws SAXException;


    
Report the end of an entity.
Params:
name – The name of the entity that is ending.
Throws:
SAXException – The application may raise an exception.
See Also:
startEntity/**
     * Report the end of an entity.
     *
     * @param name The name of the entity that is ending.
     * @exception SAXException The application may raise an exception.
     * @see #startEntity
     */
    public abstract void endEntity (String name)
        throws SAXException;


    
Report the start of a CDATA section.
The contents of the CDATA section will be reported through the regular 
characters event; this event is intended only to report the boundary.
Throws:
SAXException – The application may raise an exception.
See Also:
endCDATA/**
     * Report the start of a CDATA section.
     *
     * <p>The contents of the CDATA section will be reported through
     * the regular {@link org.xml.sax.ContentHandler#characters
     * characters} event; this event is intended only to report
     * the boundary.</p>
     *
     * @exception SAXException The application may raise an exception.
     * @see #endCDATA
     */
    public abstract void startCDATA ()
        throws SAXException;


    
Report the end of a CDATA section.
Throws:
SAXException – The application may raise an exception.
See Also:
startCDATA/**
     * Report the end of a CDATA section.
     *
     * @exception SAXException The application may raise an exception.
     * @see #startCDATA
     */
    public abstract void endCDATA ()
        throws SAXException;


    
Report an XML comment anywhere in the document.
This callback will be used for comments inside or outside the
document element, including comments in the external DTD
subset (if read).  Comments in the DTD must be properly
nested inside start/endDTD and start/endEntity events (if
used).
Params:
ch – An array holding the characters in the comment.
start – The starting position in the array.
length – The number of characters to use from the array.
Throws:
SAXException – The application may raise an exception./**
     * Report an XML comment anywhere in the document.
     *
     * <p>This callback will be used for comments inside or outside the
     * document element, including comments in the external DTD
     * subset (if read).  Comments in the DTD must be properly
     * nested inside start/endDTD and start/endEntity events (if
     * used).</p>
     *
     * @param ch An array holding the characters in the comment.
     * @param start The starting position in the array.
     * @param length The number of characters to use from the array.
     * @exception SAXException The application may raise an exception.
     */
    public abstract void comment (char ch[], int start, int length)
        throws SAXException;

}

// end of LexicalHandler.java