private void doCSSCompression(final Reader in, Writer out, final String outputFilename) throws IOException {
traceVerbose("Start doCSSCompression");
try {
// CSS compressor
final CssCompressor compressor = new CssCompressor(in);
// Close the input stream first, and then open the output stream,
// in case the output file should override the input file
closeObject(in);
// Get Writer object for output file
out = openDataWriter(new File(outputFilename), UTF8);
// Compress file
compressor.compress(out, -1);
} finally {
closeObject(out);
traceVerbose("End doCSSCompression");
}
}