// SAX DTD handler.
// No warranty; no copyright -- use this as you will.
// $Id$

package org.xml.sax;

/**
 * Receive notification of basic DTD-related 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>If a SAX application needs information about notations and
 * unparsed entities, then the application implements this 
 * interface and registers an instance with the SAX parser using 
 * the parser's setDTDHandler method.  The parser uses the 
 * instance to report notation and unparsed entity declarations to 
 * the application.</p>
 *
 * <p>Note that this interface includes only those DTD events that
 * the XML recommendation <em>requires</em> processors to report:
 * notation and unparsed entity declarations.</p>
 *
 * <p>The SAX parser may report these events in any order, regardless
 * of the order in which the notations and unparsed entities were
 * declared; however, all DTD events must be reported after the
 * document handler's startDocument event, and before the first
 * startElement event.</p>
 *
 * <p>It is up to the application to store the information for 
 * future use (perhaps in a hash table or object tree).
 * If the application encounters attributes of type "NOTATION",
 * "ENTITY", or "ENTITIES", it can use the information that it
 * obtained through this interface to find the entity and/or
 * notation corresponding with the attribute value.</p>
 *
 * @since SAX 1.0
 * @author David Megginson, 
 *         <a href="mailto:sax@megginson.com">sax@megginson.com</a>
 * @version 2.0
 * @see org.xml.sax.Parser#setDTDHandler
 * @see org.xml.sax.HandlerBase 
 */
public interface DTDHandler {
    
    
    /**
     * Receive notification of a notation declaration event.
     *
     * <p>It is up to the application to record the notation for later
     * reference, if necessary.</p>
     *
     * <p>At least one of publicId and systemId must be non-null.
     * If a system identifier is present, and it is a URL, the SAX
     * parser must resolve it fully before passing it to the
     * application through this event.</p>
     *
     * <p>There is no guarantee that the notation declaration will be
     * reported before any unparsed entities that use it.</p>
     *
     * @param name The notation name.
     * @param publicId The notation's public identifier, or null if
     *        none was given.
     * @param systemId The notation's system identifier, or null if
     *        none was given.
     * @exception org.xml.sax.SAXException Any SAX exception, possibly
     *            wrapping another exception.
     * @see #unparsedEntityDecl
     * @see org.xml.sax.AttributeList
     */
    public abstract void notationDecl (String name,
				       String publicId,
				       String systemId)
	throws SAXException;
    
    
    /**
     * Receive notification of an unparsed entity declaration event.
     *
     * <p>Note that the notation name corresponds to a notation
     * reported by the {@link #notationDecl notationDecl} event.  
     * It is up to the application to record the entity for later 
     * reference, if necessary.</p>
     *
     * <p>If the system identifier is a URL, the parser must resolve it
     * fully before passing it to the application.</p>
     *
     * @exception org.xml.sax.SAXException Any SAX exception, possibly
     *            wrapping another exception.
     * @param name The unparsed entity's name.
     * @param publicId The entity's public identifier, or null if none
     *        was given.
     * @param systemId The entity's system identifier.
     * @param notation name The name of the associated notation.
     * @see #notationDecl
     * @see org.xml.sax.AttributeList
     */
    public abstract void unparsedEntityDecl (String name,
					     String publicId,
					     String systemId,
					     String notationName)
	throws SAXException;
    
}

// end of DTDHandler.java