/*
 *  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.codehaus.groovy.control;

import groovy.lang.GroovyRuntimeException;
import org.codehaus.groovy.antlr.AntlrParserPluginFactory;

import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;

/**
 * A factory of parser plugin instances
 *
 */
public abstract class ParserPluginFactory {
    private static Class<?> ANTLR4_CLASS=null;

    /**
     * creates the ANTLR 4 parser
     * @return the factory for the parser
     */
    public static ParserPluginFactory antlr4() {
        if (ANTLR4_CLASS==null) {
            String name = "org.apache.groovy.parser.antlr4.Antlr4PluginFactory";
            try {
                ANTLR4_CLASS =
                        Class.forName(name, false, ParserPluginFactory.class.getClassLoader());
            } catch (Exception e) {
                throw new GroovyRuntimeException("Could not find or load parser plugin factory for antlr4", e);
            }
        }
        try {
            return AccessController.doPrivileged(new PrivilegedExceptionAction<ParserPluginFactory>() {
                public ParserPluginFactory run() throws Exception {
                    return (ParserPluginFactory) ANTLR4_CLASS.newInstance();
                }
            });
        } catch (PrivilegedActionException e) {
            throw new GroovyRuntimeException("Could not create instance of parser plugin factory for antlr4", e.getCause());
        }
    }

    /**
     * creates the ANTLR 2.7 parser
     * @return the factory for the parser
     */
    public static ParserPluginFactory antlr2() {
        return new AntlrParserPluginFactory();
    }

    /**
     * creates the ANTLR 2.7 parser. This method was used to switch between the pre JSR
     * parser and the new ANTLR 2.7 based parser, but even before Groovy 1.0 this
     * method was changed to always return the ANTLR 2.7 parser.
     * @param useNewParser - ignored
     * @return the ANTLR 2.7 based parser
     */
    @Deprecated
    public static ParserPluginFactory newInstance(boolean useNewParser) {
        return newInstance();
    }

    /**
     * creates the ANTLR 2.7 parser. This method was used to switch between the pre JSR
     * parser and the new ANTLR 2.7 based parser, but even before Groovy 1.0 this
     * method was changed to always return the ANTLR 2.7 parser.
     *
     * @return the new parser factory.
     */
    @Deprecated
    public static ParserPluginFactory newInstance() {
        return antlr2();
    }

    public abstract ParserPlugin createParserPlugin();
}