/*
 * Copyright 2001, 2002,2004 The Apache Software Foundation.
 * 
 * Licensed 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 com.sun.org.apache.xerces.internal.impl.dv;

import java.util.Hashtable;

/**
 * The factory to create and return DTD types. The implementation should
 * store the created datatypes in static data, so that they can be shared by
 * multiple parser instance, and multiple threads.
 * 
 * @xerces.internal 
 *
 * @author Sandy Gao, IBM
 *
 * @version $Id: DTDDVFactory.java,v 1.2.6.1 2005/09/12 10:59:45 neerajbj Exp $
 */
public abstract class DTDDVFactory {

    private static final String DEFAULT_FACTORY_CLASS = "com.sun.org.apache.xerces.internal.impl.dv.dtd.DTDDVFactoryImpl";

    /**
     * Get an instance of the default DTDDVFactory implementation.
     *
     * @return  an instance of DTDDVFactory implementation
     * @exception DVFactoryException  cannot create an instance of the specified
     *                                class name or the default class name
     */
    public static synchronized final DTDDVFactory getInstance() throws DVFactoryException {
        return getInstance(DEFAULT_FACTORY_CLASS);
    }

    /**
     * Get an instance of DTDDVFactory implementation.
     *
     * @param factoryClass  name of the implementation to load.
     * @return  an instance of DTDDVFactory implementation
     * @exception DVFactoryException  cannot create an instance of the specified
     *                                class name or the default class name
     */
    public static synchronized final DTDDVFactory getInstance(String factoryClass) throws DVFactoryException {

        try {
            // if the class name is not specified, use the default one
            return (DTDDVFactory)
                (ObjectFactory.newInstance(factoryClass, ObjectFactory.findClassLoader(), true));
        } catch (ClassCastException e) {
            throw new DVFactoryException("DTD factory class " + factoryClass + " does not extend from DTDDVFactory.");
        }
    }

    // can't create a new object of this class
    protected DTDDVFactory(){}

    /**
     * return a dtd type of the given name
     *
     * @param name  the name of the datatype
     * @return      the datatype validator of the given name
     */
    public abstract DatatypeValidator getBuiltInDV(String name);

    /**
     * get all built-in DVs, which are stored in a hashtable keyed by the name
     *
     * @return      a hashtable which contains all datatypes
     */
    public abstract Hashtable getBuiltInTypes();

}
