/*
    * 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.apache.commons.vfs2.provider.webdav;
  
  import java.lang.reflect.Constructor;
  
  import org.apache.commons.vfs2.FileSystemException;
  import org.apache.jackrabbit.webdav.DavConstants;
  import org.apache.jackrabbit.webdav.DavException;
  import org.apache.jackrabbit.webdav.client.methods.DavMethod;
  import org.apache.jackrabbit.webdav.xml.DomUtil;
  import org.w3c.dom.Element;
  
  /**
   * Converts WebDAV exceptions into FileSystemExceptions.
   *
   * @since 2.0
   */
  public final class ExceptionConverter {
  
      // avoid instanciation
      private ExceptionConverter() {
      }
  
      public static FileSystemException generate(final DavException davExc) throws FileSystemException {
          return generate(davExc, null);
      }
  
      public static FileSystemException generate(final DavException davExc, final DavMethod method)
              throws FileSystemException {
          String msg = davExc.getMessage();
          if (davExc.hasErrorCondition()) {
              try {
                  final Element error = davExc.toXml(DomUtil.BUILDER_FACTORY.newDocumentBuilder().newDocument());
                  if (DomUtil.matches(error, DavException.XML_ERROR, DavConstants.NAMESPACE) && DomUtil.hasChildElement(error, "exception", null)) {
                      final Element exc = DomUtil.getChildElement(error, "exception", null);
                      if (DomUtil.hasChildElement(exc, "message", null)) {
                          msg = DomUtil.getChildText(exc, "message", null);
                      }
                      if (DomUtil.hasChildElement(exc, "class", null)) {
                          final Class<?> cl = Class.forName(DomUtil.getChildText(exc, "class", null));
                          final Constructor<?> excConstr = cl.getConstructor(String.class);
                          final Object o = excConstr.newInstance(msg);
                          if (o instanceof FileSystemException) {
                              return (FileSystemException) o;
                          }
                          if (o instanceof Exception) {
                              return new FileSystemException(msg, (Exception) o);
                          }
                      }
                  }
              } catch (final Exception e) {
                  throw new FileSystemException(e);
              }
          }
  
          return new FileSystemException(msg);
      }
  }