public ProcessStreamReader build() {
      notNull(process, "Invalid process '" + process + "' specified");
      notNull(inputStream, "Invalid inputStream '" + inputStream + "' specified");
      isTrue(continueReadingMillis >= 0,
          "Invalid continueReadingMillis '" + continueReadingMillis + "' specified");

      switch (readingMode) {
        case NON_BLOCKING:
          return new NonBlockingProcessStreamReader(this);
        default:
          return new BlockingProcessStreamReader(this);
      }
    }
ReadingMode to use for reading InputStream
geode-core/src/main/java/org/apache/geode/internal/process/ProcessStreamReader.java