/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 */

/*

 * 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.xerces.internal.dom;

import java.util.ArrayList;

import java.util.List;

import java.util.StringTokenizer;

import org.w3c.dom.DOMImplementation;

import org.w3c.dom.DOMImplementationList;

import org.w3c.dom.DOMImplementationSource;

/**

 * Supply one the right implementation, based upon requested features. Each

 * implemented <code>DOMImplementationSource</code> object is listed in the

 * binding-specific list of available sources so that its

 * <code>DOMImplementation</code> objects are made available.

 *

 * <p>See also the

 * <a href='http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/core.html#DOMImplementationSource'>

 * Document Object Model (DOM) Level 3 Core Specification</a>.

 *

 * @xerces.internal

 *

 * @LastModified: Oct 2017

 */

public class DOMImplementationSourceImpl

    implements DOMImplementationSource {

    /**

     * A method to request a DOM implementation.

     * @param features A string that specifies which features are required.

     *   This is a space separated list in which each feature is specified

     *   by its name optionally followed by a space and a version number.

     *   This is something like: "XML 1.0 Traversal Events 2.0"

     * @return An implementation that has the desired features, or

     *   <code>null</code> if this source has none.

     */

    public DOMImplementation getDOMImplementation(String features) {

        // first check whether the CoreDOMImplementation would do

        DOMImplementation impl =

            CoreDOMImplementationImpl.getDOMImplementation();

        if (testImpl(impl, features)) {

            return impl;

        }

        // if not try the DOMImplementation

        impl = DOMImplementationImpl.getDOMImplementation();

        if (testImpl(impl, features)) {

            return impl;

        }

        return null;

    }

    /**

     * A method to request a list of DOM implementations that support the

     * specified features and versions, as specified in .

     * @param features A string that specifies which features and versions

     *   are required. This is a space separated list in which each feature

     *   is specified by its name optionally followed by a space and a

     *   version number. This is something like: "XML 3.0 Traversal +Events

     *   2.0"

     * @return A list of DOM implementations that support the desired

     *   features.

     */

    public DOMImplementationList getDOMImplementationList(String features) {

        // first check whether the CoreDOMImplementation would do

        DOMImplementation impl = CoreDOMImplementationImpl.getDOMImplementation();

        final List<DOMImplementation> implementations = new ArrayList<>();

        if (testImpl(impl, features)) {

            implementations.add(impl);

        }

        impl = DOMImplementationImpl.getDOMImplementation();

        if (testImpl(impl, features)) {

            implementations.add(impl);

        }

        return new DOMImplementationListImpl(implementations);

    }

    boolean testImpl(DOMImplementation impl, String features) {

        StringTokenizer st = new StringTokenizer(features);

        String feature = null;

        String version = null;

        if (st.hasMoreTokens()) {

           feature = st.nextToken();

        }

        while (feature != null) {

           boolean isVersion = false;

           if (st.hasMoreTokens()) {

               char c;

               version = st.nextToken();

               c = version.charAt(0);

               switch (c) {

               case '0': case '1': case '2': case '3': case '4':

               case '5': case '6': case '7': case '8': case '9':

                   isVersion = true;

               }

           } else {

               version = null;

           }

           if (isVersion) {

               if (!impl.hasFeature(feature, version)) {

                   return false;

               }

               if (st.hasMoreTokens()) {

                   feature = st.nextToken();

               } else {

                   feature = null;

               }

           } else {

               if (!impl.hasFeature(feature, null)) {

                   return false;

               }

               feature = version;

           }

        }

        return true;

    }

}