该检查将替换以下调用链:
collection.stream().forEach() → collection.forEach()collection.stream().collect(toList/toSet/toCollection()) → new CollectionType<>(collection)collection.stream().toArray() → collection.toArray()Arrays.asList().stream() → Arrays.stream() or Stream.of()IntStream.range(0, array.length).mapToObj(idx -> array[idx]) → Arrays.stream(array)IntStream.range(0, list.size()).mapToObj(idx -> list.get(idx)) → list.stream()Collections.singleton().stream() → Stream.of()Collections.emptyList().stream() → Stream.empty()stream.filter().findFirst().isPresent() → stream.anyMatch()stream.collect(counting()) → stream.count()stream.collect(maxBy()) → stream.max()stream.collect(mapping()) → stream.map().collect()stream.collect(reducing()) → stream.reduce()stream.collect(summingInt()) → stream.mapToInt().sum()stream.mapToObj(x -> x) → stream.boxed()stream.map(x -> {...; return x;}) → stream.peek(x -> ...)!stream.anyMatch() → stream.noneMatch()!stream.anyMatch(x -> !(...)) → stream.allMatch()stream.map().anyMatch(Boolean::booleanValue) → stream.anyMatch()IntStream.range(expr1, expr2).mapToObj(x -> array[x]) → Arrays.stream(array, expr1, expr2)Collection.nCopies(count, ...) → Stream.generate().limit(count)stream.sorted(comparator).findFirst() → Stream.min(comparator)optional.orElseGet(() -> { throw new ...; }) → optional.orElseThrow()
请注意,在某些情况下,替换语义可能略有差异。 例如,Collections.synchronizedList(...).stream().forEach() 不同步,而 Collections.synchronizedList(...).forEach() 同步。
另外,如果得到的元素为 null,而 Stream.max() 在本例中抛出 NullPointerException,则 collect(Collectors.maxBy()) 返回空的 Optional。