/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.xerces.impl.xs.models;

import org.apache.xerces.xni.QName;
import org.apache.xerces.impl.xs.SubstitutionGroupHandler;
import org.apache.xerces.impl.xs.XMLSchemaException;

import java.util.Vector;

/**
 * Note: State of the content model is stored in the validator
 *
 * @xerces.internal 
 *
 * @author Sandy Gao, IBM
 * @author Elena Litani, IBM
 * @version $Id: XSCMValidator.java 446729 2006-09-15 20:44:44Z mrglavas $
 */
public interface XSCMValidator {


    public static final short FIRST_ERROR = -1;

    // on subsequent errors the validator should not report
    // an error
    //
    public static final short SUBSEQUENT_ERROR = -2;

    /**
     * This methods to be called on entering a first element whose type
     * has this content model. It will return the initial state of the content model
     *
     * @return Start state of the content model
     */
    public int[] startContentModel();


    /**
     * The method corresponds to one transaction in the content model.
     *
     * @param elementName
     * @param state  Current state
     * @return element decl or wildcard decl that
     *         corresponds to the element from the Schema grammar
     */
    public Object oneTransition (QName elementName, int[] state, SubstitutionGroupHandler subGroupHandler);


    /**
     * The method indicates the end of list of children
     *
     * @param state  Current state of the content model
     * @return true if the last state was a valid final state
     */
    public boolean endContentModel (int[] state);

    /**
     * check whether this content violates UPA constraint.
     *
     * @param subGroupHandler the substitution group handler
     * @return true if this content model contains other or list wildcard
     */
    public boolean checkUniqueParticleAttribution(SubstitutionGroupHandler subGroupHandler) throws XMLSchemaException;

    /**
     * Check which elements are valid to appear at this point. This method also
     * works if the state is in error, in which case it returns what should
     * have been seen.
     * 
     * @param state  the current state
     * @return       a Vector whose entries are instances of
     *               either XSWildcardDecl or XSElementDecl.
     */
    public Vector whatCanGoHere(int[] state);
    
} // XSCMValidator
