/*
 * @(#)$Id: ExternalElementExp.java,v 1.6 2001/05/24 16:52:35 Bear Exp $
 *
 * Copyright 2001 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */
package com.sun.msv.relaxns.grammar;

import com.sun.msv.grammar.Expression;
import com.sun.msv.grammar.ElementExp;
import com.sun.msv.grammar.NameClass;
import com.sun.msv.grammar.NamespaceNameClass;
import com.sun.msv.grammar.ExpressionPool;
import com.sun.msv.grammar.ReferenceExp;
import org.iso_relax.dispatcher.ElementDecl;
import org.xml.sax.Locator;

/**
 * place holder for imported element declaration.
 * 
 * This class derives ElementExp because "elementDecl" is a constraint over one element.
 * This class also provides stub methods so that programs who are not aware to
 * divide&validate can gracefully degrade.
 * 
 * @author <a href="mailto:kohsuke.kawaguchi@eng.sun.com">Kohsuke KAWAGUCHI</a>
 */
public class ExternalElementExp extends ElementExp
{
	public NameClass getNameClass() { return nameClass; }

	/** NamespaceNameClass object that matchs this namespace. */
	private final NamespaceNameClass nameClass;
	
	/** namespace URI that this ExternalElementExp belongs to. */
	public final String namespaceURI;
	
	/** name of the imported Rule */
	public final String ruleName;
	
	/** where did this reference is written in the source file.
	 * 
	 * can be set to null (to reduce memory usage) at anytime.
	 */
	public transient Locator source;
	
	/**
	 * imported ElementDecl object that actually validates this element.
	 * this variable is set during binding phase.
	 */
	public ElementDecl rule;

	public ExternalElementExp(
		ExpressionPool pool, String namespaceURI, String ruleName,
		Locator loc )
	{
		// set content model to nullSet
		// to make this elementExp accept absolutely nothing.
		// "ignoreUndeclaredAttributes" flag is also meaningless here
		// because actual validation of this element will be done by a different
		// IslandVerifier.
		super(Expression.nullSet,false);
		
		this.ruleName = ruleName;
		this.namespaceURI = namespaceURI;
		this.nameClass = new NamespaceNameClass(namespaceURI);
		this.source = loc;
		
		/* provide dummy content model
		
			<mixed>
				<zeroOrMore>
					<choice>
						<attribute>
							<nsName/>
						</attribute>
						<<<< this >>>>
					</choice>
				</zeroOrMore>
			</mixed>
		*/
		this.contentModel = pool.createZeroOrMore(
			pool.createMixed(
				pool.createChoice(
					pool.createAttribute(nameClass),
					this ) ) );
	}
	
}