docs: public Processor setOutputDir(final File output) {
          if (!output.isAbsolute()) {
              throw new IllegalArgumentException("Output directory path must be absolute: " + output);
          }
          if (output.exists() && !output.isDirectory()) {
              throw new IllegalArgumentException("Output directory exists and is not a directory: " + output);
          }
          args.put("output.dir", output.getAbsolutePath());
          return this;
      }