@Override
 public Point get(int i) {
   int offset = 0;
   for (Points points : pointsList) {
     if (i - offset < points.size()) {
       return points.get(i - offset);
     }
     offset += points.size();
   }
   throw new NoSuchElementException();
 }
  /**
   * @throws XMLStreamException
   * @throws FactoryConfigurationError
   * @throws IOException
   * @throws UnknownCRSException
   * @throws TransformationException
   */
  @Test
  public void testLineString()
      throws XMLStreamException, FactoryConfigurationError, IOException, UnknownCRSException,
          TransformationException {
    XMLStreamReaderWrapper xmlReader =
        new XMLStreamReaderWrapper(this.getClass().getResource(BASE_DIR + LINESTRING_FILE));
    xmlReader.nextTag();

    Assert.assertEquals(XMLStreamConstants.START_ELEMENT, xmlReader.getEventType());
    Assert.assertEquals(new QName(GML21NS, "LineString"), xmlReader.getName());

    LineString lineString = new GML2GeometryReader().parseLineString(xmlReader, null);
    Assert.assertEquals(XMLStreamConstants.END_ELEMENT, xmlReader.getEventType());
    Assert.assertEquals(new QName(GML21NS, "LineString"), xmlReader.getName());

    Points controlPoints = lineString.getControlPoints();
    comparePoint(0.0, 0.0, controlPoints.get(0));
    comparePoint(20.0, 35.0, controlPoints.get(1));
    comparePoint(100.0, 100.0, controlPoints.get(2));

    Assert.assertEquals(
        CRSRegistry.lookup("http://www.opengis.net/gml/srs/epsg.xml#4326"),
        lineString.getCoordinateSystem().getWrappedCRS());

    XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
    outputFactory.setProperty("javax.xml.stream.isRepairingNamespaces", new Boolean(true));
    XMLMemoryStreamWriter memoryWriter = new XMLMemoryStreamWriter();

    SchemaLocationXMLStreamWriter writer =
        new SchemaLocationXMLStreamWriter(
            memoryWriter.getXMLStreamWriter(), SCHEMA_LOCATION_ATTRIBUTE);
    GML2GeometryWriter exporter = new GML2GeometryWriter(writer, null, null, new HashSet<String>());

    writer.setPrefix("gml", "http://www.opengis.net/gml");
    writer.setPrefix("xlink", "http://www.w3.org/1999/xlink");

    exporter.export(lineString);
    writer.flush();

    XMLAssert.assertValidity(memoryWriter.getReader(), SCHEMA_LOCATION);
  }
  /**
   * @throws XMLStreamException
   * @throws FactoryConfigurationError
   * @throws IOException
   * @throws UnknownCRSException
   * @throws TransformationException
   */
  @Test
  public void testMultiGeometry()
      throws XMLStreamException, FactoryConfigurationError, IOException, TransformationException,
          UnknownCRSException {
    XMLStreamReaderWrapper xmlReader =
        new XMLStreamReaderWrapper(this.getClass().getResource(BASE_DIR + MULTIGEOMETRY_FILE));
    xmlReader.nextTag();

    Assert.assertEquals(XMLStreamConstants.START_ELEMENT, xmlReader.getEventType());
    Assert.assertEquals(new QName(GML21NS, "MultiGeometry"), xmlReader.getName());

    MultiGeometry<?> multiGeometry = new GML2GeometryReader().parseMultiGeometry(xmlReader, null);
    assertEquals("c731", multiGeometry.getId());

    Point firstMember = (Point) multiGeometry.get(0);
    assertEquals("P6776", firstMember.getId());
    comparePoint(50.0, 50.0, firstMember);

    LineString secondMember = (LineString) multiGeometry.get(1);
    assertEquals("L21216", secondMember.getId());

    Points controlPoints = secondMember.getControlPoints();
    comparePoint(0.0, 0.0, controlPoints.get(0));
    comparePoint(0.0, 50.0, controlPoints.get(1));
    comparePoint(100.0, 50.0, controlPoints.get(2));

    Polygon thirdMember = (Polygon) multiGeometry.get(2);
    assertEquals("_877789", thirdMember.getId());

    Points points = thirdMember.getExteriorRing().getControlPoints();
    comparePoint(0.0, 0.0, points.get(0));
    comparePoint(100.0, 0.0, points.get(1));
    comparePoint(50.0, 100.0, points.get(2));
    comparePoint(0.0, 0.0, points.get(3));

    XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
    outputFactory.setProperty("javax.xml.stream.isRepairingNamespaces", new Boolean(true));
    XMLMemoryStreamWriter memoryWriter = new XMLMemoryStreamWriter();

    SchemaLocationXMLStreamWriter writer =
        new SchemaLocationXMLStreamWriter(
            memoryWriter.getXMLStreamWriter(), SCHEMA_LOCATION_ATTRIBUTE);
    GML2GeometryWriter exporter = new GML2GeometryWriter(writer, null, null, new HashSet<String>());

    writer.setPrefix("gml", "http://www.opengis.net/gml");
    writer.setPrefix("xlink", "http://www.w3.org/1999/xlink");

    exporter.export(multiGeometry);
    writer.flush();

    XMLAssert.assertValidity(memoryWriter.getReader(), SCHEMA_LOCATION);
  }
  /**
   * @throws XMLStreamException
   * @throws FactoryConfigurationError
   * @throws IOException
   * @throws UnknownCRSException
   * @throws TransformationException
   */
  @Test
  public void testMultiLineString()
      throws XMLStreamException, FactoryConfigurationError, IOException, TransformationException,
          UnknownCRSException {
    XMLStreamReaderWrapper xmlReader =
        new XMLStreamReaderWrapper(this.getClass().getResource(BASE_DIR + MULTILINESTRING_FILE));
    xmlReader.nextTag();

    Assert.assertEquals(XMLStreamConstants.START_ELEMENT, xmlReader.getEventType());
    Assert.assertEquals(new QName(GML21NS, "MultiLineString"), xmlReader.getName());

    MultiLineString multiLineString =
        new GML2GeometryReader().parseMultiLineString(xmlReader, null);
    LineString firstMember = multiLineString.get(0);

    Points controlPoints = firstMember.getControlPoints();
    comparePoint(56.1, 0.45, controlPoints.get(0));
    comparePoint(67.23, 0.98, controlPoints.get(1));

    LineString secondMember = multiLineString.get(1);

    controlPoints = secondMember.getControlPoints();
    comparePoint(46.71, 9.25, controlPoints.get(0));
    comparePoint(56.88, 10.44, controlPoints.get(1));

    LineString thirdMember = multiLineString.get(2);

    controlPoints = thirdMember.getControlPoints();
    comparePoint(324.1, 219.7, controlPoints.get(0));
    comparePoint(0.45, 4.56, controlPoints.get(1));

    XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
    outputFactory.setProperty("javax.xml.stream.isRepairingNamespaces", new Boolean(true));
    XMLMemoryStreamWriter memoryWriter = new XMLMemoryStreamWriter();

    SchemaLocationXMLStreamWriter writer =
        new SchemaLocationXMLStreamWriter(
            memoryWriter.getXMLStreamWriter(), SCHEMA_LOCATION_ATTRIBUTE);
    GML2GeometryWriter exporter = new GML2GeometryWriter(writer, null, null, new HashSet<String>());

    writer.setPrefix("gml", "http://www.opengis.net/gml");
    writer.setPrefix("xlink", "http://www.w3.org/1999/xlink");

    exporter.export(multiLineString);
    writer.flush();

    XMLAssert.assertValidity(memoryWriter.getReader(), SCHEMA_LOCATION);
  }
  /**
   * @throws XMLStreamException
   * @throws FactoryConfigurationError
   * @throws IOException
   * @throws UnknownCRSException
   * @throws TransformationException
   */
  @Test
  public void testMultiPolygon()
      throws XMLStreamException, FactoryConfigurationError, IOException, UnknownCRSException,
          TransformationException {
    XMLStreamReaderWrapper xmlReader =
        new XMLStreamReaderWrapper(this.getClass().getResource(BASE_DIR + MULTIPOLYGON_FILE));
    xmlReader.nextTag();

    Assert.assertEquals(XMLStreamConstants.START_ELEMENT, xmlReader.getEventType());
    Assert.assertEquals(new QName(GML21NS, "MultiPolygon"), xmlReader.getName());

    MultiPolygon multiPolygon = new GML2GeometryReader().parseMultiPolygon(xmlReader, null);

    Polygon firstMember = multiPolygon.get(0);
    Points points = firstMember.getExteriorRing().getControlPoints();
    comparePoint(0.0, 0.0, points.get(0));
    comparePoint(100.0, 0.0, points.get(1));
    comparePoint(100.0, 100.0, points.get(2));
    comparePoint(0.0, 100.0, points.get(3));
    comparePoint(0.0, 0.0, points.get(4));

    List<Points> innerPoints = firstMember.getInteriorRingsCoordinates();
    Points points1 = innerPoints.get(0);
    comparePoint(10.0, 10.0, points1.get(0));
    comparePoint(10.0, 40.0, points1.get(1));
    comparePoint(40.0, 40.0, points1.get(2));
    comparePoint(40.0, 10.0, points1.get(3));
    comparePoint(10.0, 10.0, points1.get(4));

    Points points2 = innerPoints.get(1);
    comparePoint(60.0, 60.0, points2.get(0));
    comparePoint(60.0, 90.0, points2.get(1));
    comparePoint(90.0, 90.0, points2.get(2));
    comparePoint(90.0, 60.0, points2.get(3));
    comparePoint(60.0, 60.0, points2.get(4));

    Polygon secondMember = multiPolygon.get(1);
    points = secondMember.getExteriorRing().getControlPoints();
    comparePoint(0.0, 0.0, points.get(0));
    comparePoint(100.0, 0.0, points.get(1));
    comparePoint(100.0, 100.0, points.get(2));
    comparePoint(0.0, 100.0, points.get(3));
    comparePoint(0.0, 0.0, points.get(4));

    Assert.assertEquals(
        CRSRegistry.lookup("http://www.opengis.net/gml/srs/epsg.xml#4326"),
        multiPolygon.getCoordinateSystem().getWrappedCRS());

    XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
    outputFactory.setProperty("javax.xml.stream.isRepairingNamespaces", new Boolean(true));
    XMLMemoryStreamWriter memoryWriter = new XMLMemoryStreamWriter();

    SchemaLocationXMLStreamWriter writer =
        new SchemaLocationXMLStreamWriter(
            memoryWriter.getXMLStreamWriter(), SCHEMA_LOCATION_ATTRIBUTE);
    GML2GeometryWriter exporter = new GML2GeometryWriter(writer, null, null, new HashSet<String>());

    writer.setPrefix("gml", "http://www.opengis.net/gml");
    writer.setPrefix("xlink", "http://www.w3.org/1999/xlink");

    exporter.export(multiPolygon);
    writer.flush();

    XMLAssert.assertValidity(memoryWriter.getReader(), SCHEMA_LOCATION);
  }
 @Override
 public int getCoordinateDimension() {
   return controlPoints.get(0).getCoordinateDimension();
 }