「Forループの代わりにIntStream使いましょう」の話

IntStreamSample.java

public class IntStreamSample {

  private int parseLength = 3;

  public List<String> parse(String target) {
    if (target == null || target.isEmpty()) {
      return Collections.emptyList();
    }

    final String parseTarget = "  " + target + "  ";

    return
        IntStream.rangeClosed(0, parseTarget.length()-parseLength)
          .mapToObj(i -> parseTarget.substring(i, i+parseLength))
          .collect(Collectors.toList());
  }
}