compression.setValue("gzip");
tar.setCompression(compression);
tar.setDestFile(dataTarGz);
for (final GemFileEntry entry : gem.getGemFiles()) {
if (entry.getSource().isFile()) {
tar.addFile(entry.getSource(), entry.getPathInGem());
}
else if (entry.getSource().isDirectory()) {
tar.addDirectory(entry.getSource(),
entry.getPathInGem());
}