content: /*
   * 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 mf.org.apache.xerces.dom;
  
  import java.util.ArrayList;
  import java.util.StringTokenizer;
  
  import mf.org.w3c.dom.DOMImplementation;
  import mf.org.w3c.dom.DOMImplementationList;
  import mf.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/>
   * <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>.
   *
   * @version $Id: DOMImplementationSourceImpl.java 603686 2007-12-12 17:51:23Z mrglavas $
   * @xerces.internal
   */
  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.
       */
      @Override
      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.
       */
      @Override
      public DOMImplementationList getDOMImplementationList(String features) {
          // first check whether the CoreDOMImplementation would do
          DOMImplementation impl = CoreDOMImplementationImpl.getDOMImplementation();
          final ArrayList 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;
      }
  }
  