/*
 * @(#)$Id: AttributeRecoveryToken.java,v 1.8 2001/10/19 23:59:20 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.verifier.regexp;

import com.sun.msv.grammar.AttributeExp;
import com.sun.msv.grammar.Expression;
import com.sun.msv.grammar.ExpressionPool;

/**
 * special AttributeToken that memorizes {@link AttributeExp} that fails to
 * validate itself.
 * 
 * @author <a href="mailto:kohsuke.kawaguchi@eng.sun.com">Kohsuke KAWAGUCHI</a>
 */
final class AttributeRecoveryToken extends AttributeToken
{
	AttributeRecoveryToken( REDocumentDeclaration docDecl,
		String namespaceURI, String localName, String qName, StringToken value ) {
		
		super( docDecl, namespaceURI, localName, qName, value );
	}
	
	private Expression failedExp = Expression.nullSet;
	
	public boolean match( AttributeExp exp ) {
		
		// Attribute name must meet the constraint of NameClass
		if(!exp.nameClass.accepts(namespaceURI,localName))	return false;
		
		// content model of the attribute must consume the value
		if(!docDecl.resCalc.calcResidual(exp.exp, value).isEpsilonReducible())
			failedExp = docDecl.pool.createChoice( failedExp, exp.exp );
		
		// accept AttributeExp regardless of its content restriction
		return true;
	}

	Expression getFailedExp() { return failedExp; }
}