gistfile1.txt

public interface HashService {
    String getHashType();
    String getChecksum(String box);
    String getChecksum(String box, boolean calculate);
}

public class FilesystemDigestHashService implements HashService {
  ...
    String getChecksum(String box) {
      getChecksum(box, true);
    }
    String getChecksum(String box, boolean calculate){
      ...
    }
}