Spliterator

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用于遍历和分割源元素的对象。

方法介绍

tryAdvance

// 如果存在元素，则执行Consumer并返回true并移至下一个元素。 如果没有元素返回false
	private static void tryAdvance() {
		List<String> list = new ArrayList<>(Arrays.asList("a", "b", "c"));
		Spliterator<String> stringSpliterator = list.spliterator();
		int a = 0;
		while (stringSpliterator.tryAdvance(System.out::println)){
			System.out.println(++a);
		}
	}

trySplit

// 将Spliterator拆分成多个来并行处理
	private static void trySplit() {
		List<String> values = new ArrayList<>(Arrays.asList("1", "2", "3", "4", "5", "6"));
		Spliterator<String> firstSpliterator = values.spliterator();
		Spliterator<String> secondSpliterator = firstSpliterator.trySplit();
		Spliterator<String> thirdSpliterator = firstSpliterator.trySplit();

		System.out.println("firstSpliterator : ");
		while (firstSpliterator.tryAdvance(System.out::println)){}

		System.out.println("secondSpliterator : ");
		while (secondSpliterator.tryAdvance(System.out::println)){}

		System.out.println("thirdSpliterator : ");
		while (thirdSpliterator.tryAdvance(System.out::println)){}
	}

forEachRemaining

// 剩余的元素传递给一个函数
	private static void forEachRemaining() {
		List<String> list = new ArrayList<>(Arrays.asList("a", "b", "c", "d", "e", "f"));
		Spliterator<String> firstSpliterator = list.spliterator();
		Spliterator<String> secondSpliterator = firstSpliterator.trySplit();

		firstSpliterator.forEachRemaining(System.out::println);
		System.out.println("-------");
		secondSpliterator.forEachRemaining(System.out::println);
	}

estimateSize

private static void estimateSizeAndCharacteristics() {
		List<String> list = new ArrayList<>(Arrays.asList("a", "b", "c", "d", "e", "f"));
		Spliterator<String> firstSpliterator = list.spliterator();

		// estimateSize表示Splirerator中待处理的元素.
		// characteristics表示这个Spliterator的特征，Spliterator有8大特征.

		// 调用一次trySplit()后，将list分成了两部分，firstSpliterator为三条 ，secondSpliterator为两条
		System.out.println("before forEachRemaining: " + firstSpliterator.estimateSize());

		// 这个Characteristics=16464，转换为16进制：Ox4050 = ORDERED or SIZED or SUBSIZED 这三个的或运算。
		System.out.println("Characteristics " + firstSpliterator.characteristics());
		firstSpliterator.forEachRemaining(System.out::println);
		// 调用forEachRemaining后，estimateSize变为0，表示所有的元素都已经被处理完毕。
		System.out.println("after forEachRemaining" + firstSpliterator.estimateSize());
	}

本文标签： Spliterator