/*
    * Copyright (c) 2008, The JUNG Authors
    *
    * All rights reserved.
    *
    * This software is open-source under the BSD license; see either
    * "license.txt" or
    * https://github.com/jrtom/jung/blob/master/LICENSE for a description.
    */
  
  package edu.uci.ics.jung.io.graphml.parser;
  
  import java.util.Iterator;
  
  import javax.xml.stream.XMLEventReader;
  import javax.xml.stream.events.Attribute;
  import javax.xml.stream.events.EndElement;
  import javax.xml.stream.events.StartElement;
  import javax.xml.stream.events.XMLEvent;
  
  import edu.uci.ics.jung.graph.Hypergraph;
  import edu.uci.ics.jung.io.GraphIOException;
  import edu.uci.ics.jung.io.graphml.*;
  
  /**
   * Parses node elements.
   *
   * @author Nathan Mittler - nathan.mittler@gmail.com
   */
  public class NodeElementParser<G extends Hypergraph<V,E>,V,E> extends AbstractElementParser<G,V,E> {
  
      public NodeElementParser(ParserContext<G,V,E> parserContext) {
          super(parserContext);
      }
      
      @SuppressWarnings("unchecked")
      public NodeMetadata parse(XMLEventReader xmlEventReader, StartElement start)
              throws GraphIOException {
  
          try {
              // Create the new node.
              NodeMetadata node = new NodeMetadata();
  
              // Parse the attributes.
              Iterator<Attribute> iterator = start.getAttributes();
              while (iterator.hasNext()) {
                  Attribute attribute = iterator.next();
                  String name = attribute.getName().getLocalPart();
                  String value = attribute.getValue();
                  if (node.getId() == null && GraphMLConstants.ID_NAME.equals(name)) {
                      node.setId(value);
                  } else {
                      node.setProperty(name, value);
                  }
              }
  
              // Make sure the name has been set.
              if (node.getId() == null) {
                  throw new GraphIOException(
                          "Element 'node' is missing attribute 'id'");
              }
  
              while (xmlEventReader.hasNext()) {
  
                  XMLEvent event = xmlEventReader.nextEvent();
                  if (event.isStartElement()) {
                      StartElement element = (StartElement) event;
  
                      String name = element.getName().getLocalPart();
                      if(GraphMLConstants.DESC_NAME.equals(name)) {
                          String desc = (String)getParser(name).parse(xmlEventReader, element);
                          node.setDescription(desc);
                      } else if(GraphMLConstants.DATA_NAME.equals(name)) {
                          DataMetadata data = (DataMetadata)getParser(name).parse(xmlEventReader, element);
                          node.addData(data);
                      } else if(GraphMLConstants.PORT_NAME.equals(name)) {
                          PortMetadata port = (PortMetadata)getParser(name).parse(xmlEventReader, element);
                          node.addPort(port);
                      } else {
                          
                          // Treat anything else as unknown
                          getUnknownParser().parse(xmlEventReader, element);
                      }
  
                  } else if (event.isEndElement()) {
                      EndElement end = (EndElement) event;
                      verifyMatch(start, end);
                      break;
                  }
              }
              
              // Apply the keys to this object.
              applyKeys(node);
  
              return node;
              
          } catch (Exception e) {
              ExceptionConverter.convert(e);
          }
 
         return null;
     }
 }