stream idea inspection warning

Posted 2020-12-20 foolash

一、idea检查警告

Can be replaced with ‘peek‘ less... (Ctrl+F1) 
Inspection info: This inspection reports stream API call chains which can be simplified. It allows to avoid creating redundant temporary objects when traversing a collection.
The following call chains are replaced by this inspection:
    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)
Note that the replacements semantic may have minor difference in some cases. For example, Collections.synchronizedList(...).stream().forEach() is not synchronized while Collections.synchronizedList(...).forEach() is synchronized. Or collect(Collectors.maxBy()) would return an empty Optional if the resulting element is null while Stream.max() will throw NullPointerException in this case.

 

 

 

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