Creating tar.gz in java using Apache Commons Compress

Compress.java

package compress;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;

import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream;
import org.apache.commons.compress.compressors.gzip.GzipCompressorOutputStream;
import org.apache.commons.compress.utils.IOUtils;

public class Compress {

  private class Bundler extends SimpleFileVisitor<Path> {

    private TarArchiveOutputStream out;
    private Path toplevel;

    public Bundler(TarArchiveOutputStream output, Path dir) {
      out = output;
      toplevel = dir;
    }

    private String getEntryName(Path path) {
      return prefix.resolve(toplevel.relativize(path)).toString();
    }

    private InputStream getInputStream(Path path)
        throws FileNotFoundException {
      FileInputStream fin = new FileInputStream(path.toFile());
      return new BufferedInputStream(fin);
    }

    @Override
    public FileVisitResult preVisitDirectory(Path dir,
        BasicFileAttributes attrs) throws IOException {
      String entryName = getEntryName(dir);

      if (!entryName.equals("")) {
        // We allow tars with no top-level, but we are not proud of it.
        TarArchiveEntry entry = new TarArchiveEntry(dir.toFile(), entryName);
        out.putArchiveEntry(entry);
        out.closeArchiveEntry();
      }

      return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
        throws IOException {
      String entryName = getEntryName(file);

      TarArchiveEntry entry = new TarArchiveEntry(file.toFile(), entryName);
      out.putArchiveEntry(entry);
      IOUtils.copy(getInputStream(file), out);
      out.closeArchiveEntry();

      return FileVisitResult.CONTINUE;
    }

  }

  private TarArchiveOutputStream output;
  private Path prefix;

  public Compress(String outputFile, String prefix) throws IOException {
    FileOutputStream fileOut = new FileOutputStream(outputFile);
    BufferedOutputStream buffOut = new BufferedOutputStream(fileOut);
    GzipCompressorOutputStream gzOut = new GzipCompressorOutputStream(buffOut);
    output = new TarArchiveOutputStream(gzOut);

    this.prefix = Paths.get(prefix);
  }

  public void close() throws IOException {
    output.close();
  }

  public void writedir(Path dir) throws IOException {
    Bundler visitor = new Bundler(output, dir);
    Files.walkFileTree(dir, visitor);
  }

  public static void main(String[] args) throws IOException {
    String file = "/tmp/archive.tar.gz";
    Compress c = new Compress(file, "sample");
    c.writedir(Paths.get("/home/tadej/studij/lalg"));
    c.writedir(Paths.get("/home/tadej/docs"));
    c.close();
  }

}