/*
 * @(#)$Id: ContentModelAcceptor.java,v 1.6 2001/08/08 19:42:38 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.Expression;
import com.sun.msv.grammar.ElementExp;
import com.sun.msv.verifier.*;
import com.sun.msv.verifier.regexp.ExpressionAcceptor;
import com.sun.msv.verifier.regexp.ElementToken;
import com.sun.msv.verifier.regexp.CombinedChildContentExpCreator;
import com.sun.msv.util.StartTagInfo;
import com.sun.msv.util.StringRef;
import java.util.Set;
import java.util.List;
import java.util.Iterator;

/**
 * base implementation for SimpleAcceptor and ComplexAcceptor
 * 
 * @author <a href="mailto:kohsuke.kawaguchi@eng.sun.com">Kohsuke KAWAGUCHI</a>
 */
public abstract class ContentModelAcceptor extends ExpressionAcceptor {
	
	protected ContentModelAcceptor(
		REDocumentDeclaration docDecl, Expression exp,
		boolean ignoreUndeclaredAttributes ) {
	
		super(docDecl,exp,ignoreUndeclaredAttributes);
	}
	
	public boolean stepForward( Acceptor child, StringRef errRef ) {
		// TODO: explicitly mention that where the error recovery should be done.
		if( child instanceof SimpleAcceptor ) {
			SimpleAcceptor sa = (SimpleAcceptor)child;
			if(sa.continuation!=null)
				// if the continuation is available,
				// the stepForward will be very fast.
				return stepForwardByContinuation( sa.continuation, errRef );
			else
				// otherwise we have to compute the residual.
				return stepForward( new ElementToken(new ElementExp[]{sa.owner}), errRef );
		}
		if( child instanceof ComplexAcceptor ) {
			ComplexAcceptor ca = (ComplexAcceptor)child;
			return stepForward(
				new ElementToken(
					(errRef!=null)?
						ca.owners:	// in error recovery mode, pretend that every owner is happy.
						ca.getSatisfiedOwners() ),
				errRef);
		}
		throw new Error();	// child must be either Simple or Complex.
	}
	
	/**
	 * creates actual Acceptor object from the computed result.
	 */
	protected Acceptor createAcceptor(
		Expression combined, Expression continuation,
		ElementExp[] primitives, int numPrimitives ) {
		
		if( primitives==null || numPrimitives<=1 ) {
			// primitives==null is possible when recovering from error.
			
			// in this special case, combined child pattern and primitive patterns are the same.
			// therefore we don't need to keep track of primitive patterns.
			return new SimpleAcceptor(
				docDecl, combined,
				(primitives==null)?null:primitives[0],
				continuation );
		}

		// TODO: implements MultipleAcceptor for cases that
		// combined expression is unnecessary but there are more than one primitive.
		
		if( com.sun.msv.driver.textui.Debug.debug )
			System.out.println("ComplexAcceptor is used");
		
		// we need a fresh array.
		ElementExp[] owners = new ElementExp[numPrimitives];
		System.arraycopy( primitives, 0, owners, 0, numPrimitives );
		
		return new ComplexAcceptor( docDecl, combined, owners );
	}
	
	// ContentModelAcceptor does not support type-assignment.
	// This will be supported by SimpleAcceptor only.
	public Object getOwnerType() { return null; }
}