/*
 * 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 java.util.Vector;

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

XSEmptyCM is a derivative of the abstract content model base class that
handles a content model with no children (elements).
This model validated on the way in.
Author:
Elena Litani, IBM, Lisa Martin, IBM
@xerces.internal
Version:
$Id: XSEmptyCM.java 806363 2009-08-20 21:18:48Z mrglavas $/**
 * XSEmptyCM is a derivative of the abstract content model base class that
 * handles a content model with no children (elements).
 *
 * This model validated on the way in.
 *
 * @xerces.internal 
 *
 * @author Elena Litani, IBM
 * @author Lisa Martin, IBM
 * @version $Id: XSEmptyCM.java 806363 2009-08-20 21:18:48Z mrglavas $
 */
public class XSEmptyCM implements XSCMValidator {

    //
    // Constants
    //

    // start the content model: did not see any children
    private static final short STATE_START = 0;
    
    private static final Vector EMPTY = new Vector(0);

    //
    // Data
    //

    //
    // XSCMValidator methods
    //

    
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
Returns:
Start state of the content model/**
     * 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(){
        return (new int[] {STATE_START});
    }


    
The method corresponds to one transaction in the content model.
Params:
elementName – the qualified name of the element
currentState – Current state
subGroupHandler – the substitution group handler
Returns:
element index corresponding to the element from the Schema grammar/**
     * The method corresponds to one transaction in the content model.
     *
     * @param elementName the qualified name of the element
     * @param currentState Current state
     * @param subGroupHandler the substitution group handler
     * @return element index corresponding to the element from the Schema grammar
     */
    public Object oneTransition (QName elementName, int[] currentState, SubstitutionGroupHandler subGroupHandler){

        // error state
        if (currentState[0] < 0) {
            currentState[0] = XSCMValidator.SUBSEQUENT_ERROR;
            return null;
        }

        currentState[0] = XSCMValidator.FIRST_ERROR;
        return null;
    }


    
The method indicates the end of list of children
Params:
currentState – Current state of the content model
Returns:
true if the last state was a valid final state/**
     * The method indicates the end of list of children
     *
     * @param currentState Current state of the content model
     * @return true if the last state was a valid final state
     */
    public boolean endContentModel (int[] currentState){
        boolean isFinal =  false;
        int state = currentState[0];

        // restore content model state:

        // error
        if (state < 0) {
            return false;
        }


        return true;
    }

    
check whether this content violates UPA constraint.
Params:
subGroupHandler – the substitution group handler
Returns:
true if this content model contains other or list wildcard/**
     * 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 {
        return false;
    }

    
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.
Params:
state –  the current state
Returns:
      a Vector whose entries are instances of
              either XSWildcardDecl or XSElementDecl./**
     * 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) {
        return EMPTY;
    }
    
    public int [] occurenceInfo(int[] state) {
        return null;
    }
    
    public String getTermName(int termId) {
        return null;
    }
    
    public boolean isCompactedForUPA() {
        return false;
    }
} // class XSEmptyCM