/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/**

 * 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 com.sun.org.apache.xml.internal.security.utils;

/**

 * A Factory to return an XPathAPI instance. If Xalan is available it returns XalanXPathAPI. If not, then

 * it returns JDKXPathAPI.

 */

public abstract class XPathFactory {

    private static boolean xalanInstalled;

    static {

        try {

            Class<?> funcTableClass =

                ClassLoaderUtils.loadClass("com.sun.org.apache.xpath.internal.compiler.FunctionTable", XPathFactory.class);

            if (funcTableClass != null) {

                xalanInstalled = true;

            }

        } catch (Exception e) { //NOPMD

            //ignore

        }

    }

    protected static synchronized boolean isXalanInstalled() {

        return xalanInstalled;

    }

    /**

     * Get a new XPathFactory instance

     */

    public static XPathFactory newInstance() {

        if (!isXalanInstalled()) {

            return new JDKXPathFactory();

        }

        // Xalan is available

        if (XalanXPathAPI.isInstalled()) {

            return new XalanXPathFactory();

        }

        // Some problem was encountered in fixing up the Xalan FunctionTable so fall back to the

        // JDK implementation

        return new JDKXPathFactory();

    }

    /**

     * Get a new XPathAPI instance

     */

    public abstract XPathAPI newXPathAPI();

}