package org.apache.maven.plugins.shade.resource;
   
   /*
    * 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.
   */
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.StringReader;
  import java.util.Iterator;
  import java.util.List;
  import java.util.jar.JarEntry;
  import java.util.jar.JarOutputStream;
  
  import org.apache.maven.plugins.shade.relocation.Relocator;
  import org.jdom2.Attribute;
  import org.jdom2.Content;
  import org.jdom2.Document;
  import org.jdom2.Element;
  import org.jdom2.JDOMException;
  import org.jdom2.input.SAXBuilder;
  import org.jdom2.output.Format;
  import org.jdom2.output.XMLOutputter;
  import org.xml.sax.EntityResolver;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  
  /**
   * Appends multiple occurrences of some XML file.
   */
  public class XmlAppendingTransformer
      extends AbstractCompatibilityTransformer
  {
      public static final String XSI_NS = "http://www.w3.org/2001/XMLSchema-instance";
  
      boolean ignoreDtd = true;
  
      String resource;
  
      Document doc;
  
      private long time = Long.MIN_VALUE;
  
      public boolean canTransformResource( String r )
      {
          return resource != null && resource.equalsIgnoreCase( r );
      }
  
      public void processResource( String resource, InputStream is, List<Relocator> relocators, long time )
          throws IOException
      {
          Document r;
          try
          {
              SAXBuilder builder = new SAXBuilder( false );
              builder.setExpandEntities( false );
              if ( ignoreDtd )
              {
                  builder.setEntityResolver( new EntityResolver()
                  {
                      public InputSource resolveEntity( String publicId, String systemId )
                          throws SAXException, IOException
                      {
                          return new InputSource( new StringReader( "" ) );
                      }
                  } );
              }
              r = builder.build( is );
          }
          catch ( JDOMException e )
          {
              throw new RuntimeException( "Error processing resource " + resource + ": " + e.getMessage(), e );
          }
  
          if ( doc == null )
          {
              doc = r;
          }
          else
          {
              Element root = r.getRootElement();
  
              for ( Iterator<Attribute> itr = root.getAttributes().iterator(); itr.hasNext(); )
              {
                 Attribute a = itr.next();
                 itr.remove();
 
                 Element mergedEl = doc.getRootElement();
                 Attribute mergedAtt = mergedEl.getAttribute( a.getName(), a.getNamespace() );
                 if ( mergedAtt == null )
                 {
                     mergedEl.setAttribute( a );
                 }
             }
 
             for ( Iterator<Element> itr = root.getChildren().iterator(); itr.hasNext(); )
             {
                 Content n = itr.next();
                 itr.remove();
 
                 doc.getRootElement().addContent( n );
             }
         }
 
         if ( time > this.time )
         {
             this.time = time;        
         }
     }
 
     public boolean hasTransformedResource()
     {
         return doc != null;
     }
 
     public void modifyOutputStream( JarOutputStream jos )
         throws IOException
     {
         JarEntry jarEntry = new JarEntry( resource );
         jarEntry.setTime( time );
         jos.putNextEntry( jarEntry );
 
         new XMLOutputter( Format.getPrettyFormat() ).output( doc, jos );
 
         doc = null;
     }
 }