protected boolean loadTile(Tile tile, java.net.URL url) {
    if (WWIO.isFileOutOfDate(url, this.placeNameServiceSet.getExpiryTime())) {
      // The file has expired. Delete it then request download of newer.
      this.getDataFileStore().removeFile(url);
      String message = Logging.getMessage("generic.DataFileExpired", url);
      Logging.logger().fine(message);
      return false;
    }

    PlaceNameChunk tileData;
    synchronized (this.fileLock) {
      tileData = readTileData(tile, url);
    }

    if (tileData == null) {
      // Assume that something's wrong with the file and delete it.
      this.getDataFileStore().removeFile(url);
      tile.getPlaceNameService()
          .markResourceAbsent(tile.getPlaceNameService().getTileNumber(tile.row, tile.column));
      String message = Logging.getMessage("generic.DeletedCorruptDataFile", url);
      Logging.logger().fine(message);
      return false;
    }

    tile.setDataChunk(tileData);
    WorldWind.getMemoryCache(Tile.class.getName()).add(tile.getFileCachePath(), tile);
    return true;
  }
  protected static boolean isTileVisible(
      DrawContext dc, Tile tile, double minDistanceSquared, double maxDistanceSquared) {
    if (!tile.getSector().intersects(dc.getVisibleSector())) return false;

    View view = dc.getView();
    Position eyePos = view.getEyePosition();
    if (eyePos == null) return false;

    Angle lat =
        clampAngle(
            eyePos.getLatitude(),
            tile.getSector().getMinLatitude(),
            tile.getSector().getMaxLatitude());
    Angle lon =
        clampAngle(
            eyePos.getLongitude(),
            tile.getSector().getMinLongitude(),
            tile.getSector().getMaxLongitude());
    Vec4 p = dc.getGlobe().computePointFromPosition(lat, lon, 0d);
    double distSquared = dc.getView().getEyePoint().distanceToSquared3(p);
    //noinspection RedundantIfStatement
    if (minDistanceSquared > distSquared || maxDistanceSquared < distSquared) return false;

    return true;
  }
  protected void requestTile(DrawContext dc, Tile tile) {
    Vec4 centroid = dc.getGlobe().computePointFromPosition(tile.getSector().getCentroid(), 0);
    if (this.getReferencePoint() != null)
      tile.setPriority(centroid.distanceTo3(this.getReferencePoint()));

    RequestTask task = new RequestTask(tile, this);
    this.getRequestQ().add(task);
  }
    @Override
    public boolean equals(Object o) {
      if (this == o) return true;
      if (o == null || getClass() != o.getClass()) return false;

      final Tile tile = (Tile) o;

      return !(this.getFileCachePath() != null
          ? !this.getFileCachePath().equals(tile.getFileCachePath())
          : tile.getFileCachePath() != null);
    }
    public void run() {
      if (this.tile.isTileInMemoryWithData()) return;

      final java.net.URL tileURL =
          this.layer.getDataFileStore().findFile(tile.getFileCachePath(), false);
      if (tileURL != null) {
        if (this.layer.loadTile(this.tile, tileURL)) {
          tile.getPlaceNameService()
              .unmarkResourceAbsent(
                  tile.getPlaceNameService().getTileNumber(tile.row, tile.column));
          this.layer.firePropertyChange(AVKey.LAYER, null, this);
          return;
        }
      }

      this.layer.downloadTile(this.tile);
    }
    public boolean equals(Object o) {
      if (this == o) return true;
      if (o == null || getClass() != o.getClass()) return false;

      final RequestTask that = (RequestTask) o;

      // Don't include layer in comparison so that requests are shared among layers
      return !(tile != null ? !tile.equals(that.tile) : that.tile != null);
    }
 public List<Tile> getTiles() {
   if (tileKeys.isEmpty()) {
     Tile[] tiles = buildTiles(this.placeNameService, this);
     // load tileKeys
     for (Tile t : tiles) {
       tileKeys.add(t.getFileCachePath());
       WorldWind.getMemoryCache(Tile.class.getName()).add(t.getFileCachePath(), t);
     }
     return Arrays.asList(tiles);
   } else {
     List<Tile> dataTiles = new ArrayList<Tile>();
     for (String s : tileKeys) {
       Tile t = (Tile) WorldWind.getMemoryCache(Tile.class.getName()).getObject(s);
       if (t != null) {
         dataTiles.add(t);
       }
     }
     return dataTiles;
   }
 }
  protected void downloadTile(final Tile tile, DownloadPostProcessor postProcessor) {
    if (!this.isNetworkRetrievalEnabled()) return;

    if (!WorldWind.getRetrievalService().isAvailable()) return;

    java.net.URL url;
    try {
      url = tile.getRequestURL();
      if (WorldWind.getNetworkStatus().isHostUnavailable(url)) return;
    } catch (java.net.MalformedURLException e) {
      Logging.logger()
          .log(
              java.util.logging.Level.SEVERE,
              Logging.getMessage("layers.PlaceNameLayer.ExceptionCreatingUrl", tile),
              e);
      return;
    }

    Retriever retriever;

    if ("http".equalsIgnoreCase(url.getProtocol()) || "https".equalsIgnoreCase(url.getProtocol())) {
      if (postProcessor == null) postProcessor = new DownloadPostProcessor(this, tile);
      retriever = new HTTPRetriever(url, postProcessor);
    } else {
      Logging.logger()
          .severe(
              Logging.getMessage("layers.PlaceNameLayer.UnknownRetrievalProtocol", url.toString()));
      return;
    }

    // Apply any overridden timeouts.
    Integer cto = AVListImpl.getIntegerValue(this, AVKey.URL_CONNECT_TIMEOUT);
    if (cto != null && cto > 0) retriever.setConnectTimeout(cto);
    Integer cro = AVListImpl.getIntegerValue(this, AVKey.URL_READ_TIMEOUT);
    if (cro != null && cro > 0) retriever.setReadTimeout(cro);
    Integer srl = AVListImpl.getIntegerValue(this, AVKey.RETRIEVAL_QUEUE_STALE_REQUEST_LIMIT);
    if (srl != null && srl > 0) retriever.setStaleRequestLimit(srl);

    WorldWind.getRetrievalService().runRetriever(retriever, tile.getPriority());
  }
  protected Tile[] buildTiles(PlaceNameService placeNameService, NavigationTile navTile) {
    final Angle dLat = placeNameService.getTileDelta().getLatitude();
    final Angle dLon = placeNameService.getTileDelta().getLongitude();

    // Determine the row and column offset from the global tiling origin for the southwest tile
    // corner
    int firstRow = Tile.computeRow(dLat, navTile.navSector.getMinLatitude());
    int firstCol = Tile.computeColumn(dLon, navTile.navSector.getMinLongitude());
    int lastRow = Tile.computeRow(dLat, navTile.navSector.getMaxLatitude().subtract(dLat));
    int lastCol = Tile.computeColumn(dLon, navTile.navSector.getMaxLongitude().subtract(dLon));

    int nLatTiles = lastRow - firstRow + 1;
    int nLonTiles = lastCol - firstCol + 1;

    Tile[] tiles = new Tile[nLatTiles * nLonTiles];

    Angle p1 = Tile.computeRowLatitude(firstRow, dLat);
    for (int row = 0; row <= lastRow - firstRow; row++) {
      Angle p2;
      p2 = p1.add(dLat);

      Angle t1 = Tile.computeColumnLongitude(firstCol, dLon);
      for (int col = 0; col <= lastCol - firstCol; col++) {
        Angle t2;
        t2 = t1.add(dLon);
        // Need offset row and column to correspond to total ro/col numbering
        tiles[col + row * nLonTiles] =
            new Tile(placeNameService, new Sector(p1, p2, t1, t2), row + firstRow, col + firstCol);
        t1 = t2;
      }
      p1 = p2;
    }

    return tiles;
  }
  protected void drawOrRequestTile(
      DrawContext dc,
      Tile tile,
      double minDisplayDistanceSquared,
      double maxDisplayDistanceSquared) {
    if (!isTileVisible(dc, tile, minDisplayDistanceSquared, maxDisplayDistanceSquared)) return;

    if (tile.isTileInMemoryWithData()) {
      PlaceNameChunk placeNameChunk = tile.getDataChunk();
      if (placeNameChunk.numEntries > 0) {
        Iterable<GeographicText> renderIter = placeNameChunk.makeIterable(dc);
        this.placeNameRenderer.render(dc, renderIter);
      }
      return;
    }

    // Tile's data isn't available, so request it
    if (!tile.getPlaceNameService()
        .isResourceAbsent(tile.getPlaceNameService().getTileNumber(tile.row, tile.column))) {
      this.requestTile(dc, tile);
    }
  }
  protected static PlaceNameChunk readTileData(Tile tile, java.net.URL url) {
    java.io.InputStream is = null;

    try {
      String path = url.getFile();
      path =
          path.replaceAll(
              "%20", " "); // TODO: find a better way to get a path usable by FileInputStream

      java.io.FileInputStream fis = new java.io.FileInputStream(path);
      java.io.BufferedInputStream buf = new java.io.BufferedInputStream(fis);
      is = new java.util.zip.GZIPInputStream(buf);

      GMLPlaceNameSAXHandler handler = new GMLPlaceNameSAXHandler();
      javax.xml.parsers.SAXParserFactory.newInstance().newSAXParser().parse(is, handler);
      return handler.createPlaceNameChunk(tile.getPlaceNameService());
    } catch (Exception e) {
      // todo log actual error
      Logging.logger()
          .log(
              Level.FINE,
              Logging.getMessage(
                  "layers.PlaceNameLayer.ExceptionAttemptingToReadFile", url.toString()),
              e);
    } finally {
      try {
        if (is != null) is.close();
      } catch (java.io.IOException e) {
        Logging.logger()
            .log(
                Level.FINE,
                Logging.getMessage(
                    "layers.PlaceNameLayer.ExceptionAttemptingToReadFile", url.toString()),
                e);
      }
    }

    return null;
  }
  private static MeshTile[] createTiles(LevelSet levelSet, int levelNumber, MeshCoords coords) {
    Sector sector = levelSet.getSector();
    Level level = levelSet.getLevel(levelNumber);
    Angle dLat = level.getTileDelta().getLatitude();
    Angle dLon = level.getTileDelta().getLongitude();
    Angle latOrigin = levelSet.getTileOrigin().getLatitude();
    Angle lonOrigin = levelSet.getTileOrigin().getLongitude();

    // Determine the row and column offset from the common World Wind global tiling origin.
    int firstRow = Tile.computeRow(dLat, sector.getMinLatitude(), latOrigin);
    int firstCol = Tile.computeColumn(dLon, sector.getMinLongitude(), lonOrigin);
    int lastRow = Tile.computeRow(dLat, sector.getMaxLatitude(), latOrigin);
    int lastCol = Tile.computeColumn(dLon, sector.getMaxLongitude(), lonOrigin);

    int numLatTiles = lastRow - firstRow + 1;
    int numLonTiles = lastCol - firstCol + 1;

    AffineTransform sectorTransform = createTransform(sector, coords);

    MeshTile[] tiles = new MeshTile[numLatTiles * numLonTiles];
    int index = 0;

    Angle p1 = Tile.computeRowLatitude(firstRow, dLat, latOrigin);

    for (int row = firstRow; row <= lastRow; row++) {
      Angle p2 = p1.add(dLat);

      Angle t1 = Tile.computeColumnLongitude(firstCol, dLon, lonOrigin);

      for (int col = firstCol; col <= lastCol; col++) {
        Angle t2 = t1.add(dLon);

        Sector tileSector = new Sector(p1, p2, t1, t2);
        MeshCoords tileCoords = transformSector(sectorTransform, tileSector);
        tiles[index++] = new MeshTile(tileSector, level, row, col, tileCoords);

        t1 = t2;
      }
      p1 = p2;
    }

    return tiles;
  }
 public int hashCode() {
   return (tile != null ? tile.hashCode() : 0);
 }
 protected boolean isTileInMemoryWithData() {
   Tile t =
       (Tile) WorldWind.getMemoryCache(Tile.class.getName()).getObject(this.getFileCachePath());
   return !(t == null || t.getDataChunk() == null);
 }