java~lambda表達式讓查詢更優雅

  /**
   * lambda filter.
   * @param list
   * @param predicate
   * @return
   */
  public List<User> conditionFilter(List<User> list, Predicate<User> predicate){
    return list.stream().filter(predicate).collect(Collectors.toList());
  }

 /**
   * find list.
   */
  public void findList() {
    List<User> list = new ArrayList<>();
    list.add(new User("zzl"));
    list.add(new User("abc"));
    list.add(new User("bca"));
    list = conditionFilter(list, exe -> exe.getName() == "zzl");
    for (User user : list
        ) {
      System.out.println(user.getName());

    }

  }

 /**
   * lambda filter not.
   *
   * @param subjects
   * @param predicate
   * @return
   */
  private List<User> conditionFilterNot(List<User> subjects, Predicate<User> predicate) {

    return subjects.stream().filter(predicate.negate()).collect(Collectors.toList());
  }

@FunctionalInterface
public interface Consumer<T> {

    void accept(T t);
  
    default Consumer<T> andThen(Consumer<? super T> after) {
        Objects.requireNonNull(after);
        return (T t) -> { accept(t); after.accept(t); };
    }
}

  private void logger(Consumer<String> action, String msg) {
    action.accept(msg);
  }

 @Test
  public void lambda() {
    logger(i -> System.out.println(i), "hello");
  }

 @Test
  public void lambdaLog() {
    logger(i -> logger.info(i), "hello");
  }