Java Spliterator.IMMUTABLE属性代码示例

/**
 * Returns an infinite sequential ordered {@code DoubleStream} produced by iterative
 * application of a function {@code f} to an initial element {@code seed},
 * producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
 * {@code f(f(seed))}, etc.
 *
 * <p>The first element (position {@code 0}) in the {@code DoubleStream}
 * will be the provided {@code seed}.  For {@code n > 0}, the element at
 * position {@code n}, will be the result of applying the function {@code f}
 *  to the element at position {@code n - 1}.
 *
 * <p>The action of applying {@code f} for one element
 * <a href="../concurrent/package-summary.html#MemoryVisibility"><i>happens-before</i></a>
 * the action of applying {@code f} for subsequent elements.  For any given
 * element the action may be performed in whatever thread the library
 * chooses.
 *
 * @param seed the initial element
 * @param f a function to be applied to the previous element to produce
 *          a new element
 * @return a new sequential {@code DoubleStream}
 */
public static DoubleStream iterate(final double seed, final DoubleUnaryOperator f) {
    Objects.requireNonNull(f);
    Spliterator.OfDouble spliterator = new Spliterators.AbstractDoubleSpliterator(Long.MAX_VALUE,
           Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL) {
        double prev;
        boolean started;

        @Override
        public boolean tryAdvance(DoubleConsumer action) {
            Objects.requireNonNull(action);
            double t;
            if (started)
                t = f.applyAsDouble(prev);
            else {
                t = seed;
                started = true;
            }
            action.accept(prev = t);
            return true;
        }
    };
    return StreamSupport.doubleStream(spliterator, false);
}
 

@Override
public Stream<URL> resources(String name) {
    Objects.requireNonNull(name);
    // ordering not specified
    int characteristics = (Spliterator.NONNULL | Spliterator.IMMUTABLE |
                           Spliterator.SIZED | Spliterator.SUBSIZED);
    Supplier<Spliterator<URL>> supplier = () -> {
        try {
            List<URL> urls = findResourcesAsList(name);
            return Spliterators.spliterator(urls, characteristics);
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    };
    Stream<URL> s1 = StreamSupport.stream(supplier, characteristics, false);
    Stream<URL> s2 = parent.resources(name);
    return Stream.concat(s1, s2);
}
 

/**
 * Returns an infinite sequential ordered {@code IntStream} produced by iterative
 * application of a function {@code f} to an initial element {@code seed},
 * producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
 * {@code f(f(seed))}, etc.
 *
 * <p>The first element (position {@code 0}) in the {@code IntStream} will be
 * the provided {@code seed}.  For {@code n > 0}, the element at position
 * {@code n}, will be the result of applying the function {@code f} to the
 * element at position {@code n - 1}.
 *
 * <p>The action of applying {@code f} for one element
 * <a href="../concurrent/package-summary.html#MemoryVisibility"><i>happens-before</i></a>
 * the action of applying {@code f} for subsequent elements.  For any given
 * element the action may be performed in whatever thread the library
 * chooses.
 *
 * @param seed the initial element
 * @param f a function to be applied to the previous element to produce
 *          a new element
 * @return a new sequential {@code IntStream}
 */
public static IntStream iterate(final int seed, final IntUnaryOperator f) {
    Objects.requireNonNull(f);
    Spliterator.OfInt spliterator = new Spliterators.AbstractIntSpliterator(Long.MAX_VALUE,
           Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL) {
        int prev;
        boolean started;

        @Override
        public boolean tryAdvance(IntConsumer action) {
            Objects.requireNonNull(action);
            int t;
            if (started)
                t = f.applyAsInt(prev);
            else {
                t = seed;
                started = true;
            }
            action.accept(prev = t);
            return true;
        }
    };
    return StreamSupport.intStream(spliterator, false);
}
 

@Override
public int characteristics() {
    return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED |
           Spliterator.IMMUTABLE | Spliterator.NONNULL |
           Spliterator.DISTINCT | Spliterator.SORTED;
}
 

@Override
public int characteristics() {
    return Spliterator.DISTINCT + Spliterator.NONNULL + Spliterator.IMMUTABLE;
}
 

public int characteristics() {
    return (Spliterator.SIZED | Spliterator.SUBSIZED |
            Spliterator.NONNULL | Spliterator.IMMUTABLE);
}