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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

 *

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package org.xml.sax.ext;

import org.xml.sax.SAXException;

/**

 * SAX2 extension handler for lexical events.

 *

 * <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.

     *

     * <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.

     *

     * <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.

     *

     * <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.

     *

     * @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.

     *

     * <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.

     *

     * @exception SAXException The application may raise an exception.

     * @see #startCDATA

     */

    public abstract void endCDATA ()

        throws SAXException;

    /**

     * 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