/*
 * 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.jaxp.validation;

import org.apache.xerces.xni.grammars.Grammar;
import org.apache.xerces.xni.grammars.XMLGrammarDescription;
import org.apache.xerces.xni.grammars.XMLGrammarPool;

/**
 * <p>Implementation of Schema for W3C XML Schemas
 * which contains no schema components.</p>
 * 
 * @author Michael Glavassevich, IBM
 * @version $Id: EmptyXMLSchema.java 598686 2007-11-27 16:49:14Z knoaman $
 */
final class EmptyXMLSchema extends AbstractXMLSchema implements XMLGrammarPool {
    
    /** Zero length grammar array. */
    private static final Grammar [] ZERO_LENGTH_GRAMMAR_ARRAY = new Grammar [0];

    public EmptyXMLSchema(String xsdVersion) {
    	super(xsdVersion);
    }
    
    /*
     * XMLGrammarPool methods
     */

    public Grammar[] retrieveInitialGrammarSet(String grammarType) {
        return ZERO_LENGTH_GRAMMAR_ARRAY;
    }

    public void cacheGrammars(String grammarType, Grammar[] grammars) {}

    public Grammar retrieveGrammar(XMLGrammarDescription desc) {
        return null;
    }

    public void lockPool() {}

    public void unlockPool() {}

    public void clear() {}
    
    /*
     * XSGrammarPoolContainer methods
     */

    public XMLGrammarPool getGrammarPool() {
        return this;
    }

    public boolean isFullyComposed() {
        return true;
    }

} // EmptyXMLSchema
