// DeclHandler.java - Optional handler for DTD declaration events.
// Public Domain: no warranty.
// $Id: DeclHandler.java,v 1.1.1.1 2000/11/23 01:53:36 edwingo Exp $

package org.xml.sax.ext;

import org.xml.sax.SAXException;


/**
 * SAX2 extension handler for DTD declaration events.
 *
 * <blockquote>
 * <em>This module, both source code and documentation, is in the
 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
 * </blockquote>
 *
 * <p>This is an optional extension handler for SAX2 to provide
 * information about DTD declarations in an XML document.  XML
 * readers are not required to support this handler, and this
 * handler is not included in the core SAX2 distribution.</p>
 *
 * <p>Note that data-related DTD declarations (unparsed entities and
 * notations) are already reported through the {@link
 * org.xml.sax.DTDHandler DTDHandler} interface.</p>
 *
 * <p>If you are using the declaration handler together with a lexical
 * handler, all of the events will occur between the
 * {@link org.xml.sax.ext.LexicalHandler#startDTD startDTD} and the
 * {@link org.xml.sax.ext.LexicalHandler#endDTD endDTD} events.</p>
 *
 * <p>To set the DeclHandler for an XML reader, use the
 * {@link org.xml.sax.XMLReader#setProperty setProperty} method
 * with the propertyId "http://xml.org/sax/properties/declaration-handler".
 * If the reader does not support declaration events, it will throw a
 * {@link org.xml.sax.SAXNotRecognizedException SAXNotRecognizedException}
 * or a
 * {@link org.xml.sax.SAXNotSupportedException SAXNotSupportedException}
 * when you attempt to register the handler.</p>
 *
 * @since 1.0
 * @author David Megginson, 
 *         <a href="mailto:sax@megginson.com">sax@megginson.com</a>
 * @version 1.0
 * @see org.xml.sax.XMLReader
 */
public interface DeclHandler
{

    /**
     * Report an element type declaration.
     *
     * <p>The content model will consist of the string "EMPTY", the
     * string "ANY", or a parenthesised group, optionally followed
     * by an occurrence indicator.  The model will be normalized so
     * that all parameter entities are fully resolved and all whitespace 
     * is removed,and will include the enclosing parentheses.  Other
     * normalization (such as removing redundant parentheses or 
     * simplifying occurrence indicators) is at the discretion of the
     * parser.</p>
     *
     * @param name The element type name.
     * @param model The content model as a normalized string.
     * @exception SAXException The application may raise an exception.
     */
    public abstract void elementDecl (String name, String model)
	throws SAXException;


    /**
     * Report an attribute type declaration.
     *
     * <p>Only the effective (first) declaration for an attribute will
     * be reported.  The type will be one of the strings "CDATA",
     * "ID", "IDREF", "IDREFS", "NMTOKEN", "NMTOKENS", "ENTITY",
     * "ENTITIES", a parenthesized token group with 
     * the separator "|" and all whitespace removed, or the word
     * "NOTATION" followed by a space followed by a parenthesized
     * token group with all whitespace removed.</p>
     *
     * <p>Any parameter entities in the attribute value will be
     * expanded, but general entities will not.</p>
     *
     * @param eName The name of the associated element.
     * @param aName The name of the attribute.
     * @param type A string representing the attribute type.
     * @param valueDefault A string representing the attribute default
     *        ("#IMPLIED", "#REQUIRED", or "#FIXED") or null if
     *        none of these applies.
     * @param value A string representing the attribute's default value,
     *        or null if there is none.
     * @exception SAXException The application may raise an exception.
     */
    public abstract void attributeDecl (String eName,
					String aName,
					String type,
					String valueDefault,
					String value)
	throws SAXException;


    /**
     * Report an internal entity declaration.
     *
     * <p>Only the effective (first) declaration for each entity
     * will be reported.  All parameter entities in the value
     * will be expanded, but general entities will not.</p>
     *
     * @param name The name of the entity.  If it is a parameter
     *        entity, the name will begin with '%'.
     * @param value The replacement text of the entity.
     * @exception SAXException The application may raise an exception.
     * @see #externalEntityDecl
     * @see org.xml.sax.DTDHandler#unparsedEntityDecl
     */
    public abstract void internalEntityDecl (String name, String value)
	throws SAXException;


    /**
     * Report a parsed external entity declaration.
     *
     * <p>Only the effective (first) declaration for each entity
     * will be reported.</p>
     *
     * @param name The name of the entity.  If it is a parameter
     *        entity, the name will begin with '%'.
     * @param publicId The declared public identifier of the entity, or
     *        null if none was declared.
     * @param systemId The declared system identifier of the entity.
     * @exception SAXException The application may raise an exception.
     * @see #internalEntityDecl
     * @see org.xml.sax.DTDHandler#unparsedEntityDecl
     */
    public abstract void externalEntityDecl (String name, String publicId,
					     String systemId)
	throws SAXException;

}

// end of DeclHandler.java
