内部更改限制和无序流

更改发生在Java 9 beta 103和Java 9 beta
120（JDK‑8154387）之间。

负责的班级是

StreamSpliterators.UnorderedSliceSpliterator.OfInt

StreamSpliterators.UnorderedSliceSpliterator

该类的旧版本看起来像

abstract static class UnorderedSliceSpliterator<T, T_SPLITR extends Spliterator<T>> {    static final int CHUNK_SIZE = 1 << 7;    // The spliterator to slice    protected final T_SPLITR s;    protected final boolean unlimited;    private final long skipThreshold;    private final AtomicLong permits;    UnorderedSliceSpliterator(T_SPLITR s, long skip, long limit) {        this.s = s;        this.unlimited = limit < 0;        this.skipThreshold = limit >= 0 ? limit : 0;        this.permits = new AtomicLong(limit >= 0 ? skip + limit : skip);    }    UnorderedSliceSpliterator(T_SPLITR s,        UnorderedSliceSpliterator<T, T_SPLITR> parent) {        this.s = s;        this.unlimited = parent.unlimited;        this.permits = parent.permits;        this.skipThreshold = parent.skipThreshold;    }

…

        @Override        public void forEachRemaining(Consumer<? super T> action) { Objects.requireNonNull(action); ArrayBuffer.OfRef<T> sb = null; PermitStatus permitStatus; while ((permitStatus = permitStatus()) != PermitStatus.NO_MORE) {     if (permitStatus == PermitStatus.MAYBE_MORE) {         // Optimistically traverse elements up to a threshold of CHUNK_SIZE         if (sb == null)  sb = new ArrayBuffer.OfRef<>(CHUNK_SIZE);         else  sb.reset();         long permitsRequested = 0;         do { } while (s.tryAdvance(sb) && ++permitsRequested < CHUNK_SIZE);         if (permitsRequested == 0)  return;         sb.forEach(action, acquirePermits(permitsRequested));     }     else {         // Must be UNLIMITED; let 'er rip         s.forEachRemaining(action);         return;     } }        }

如我们所见，它尝试

CHUNK_SIZE = 1 << 7

相反，新版本看起来像

abstract static class UnorderedSliceSpliterator<T, T_SPLITR extends Spliterator<T>> {    static final int CHUNK_SIZE = 1 << 7;    // The spliterator to slice    protected final T_SPLITR s;    protected final boolean unlimited;    protected final int chunkSize;    private final long skipThreshold;    private final AtomicLong permits;    UnorderedSliceSpliterator(T_SPLITR s, long skip, long limit) {        this.s = s;        this.unlimited = limit < 0;        this.skipThreshold = limit >= 0 ? limit : 0;        this.chunkSize = limit >= 0 ? (int)Math.min(CHUNK_SIZE, ((skip + limit) / AbstractTask.LEAF_TARGET) + 1) : CHUNK_SIZE;        this.permits = new AtomicLong(limit >= 0 ? skip + limit : skip);    }    UnorderedSliceSpliterator(T_SPLITR s,        UnorderedSliceSpliterator<T, T_SPLITR> parent) {        this.s = s;        this.unlimited = parent.unlimited;        this.permits = parent.permits;        this.skipThreshold = parent.skipThreshold;        this.chunkSize = parent.chunkSize;    }

…

        @Override        public void forEachRemaining(Consumer<? super T> action) { Objects.requireNonNull(action); ArrayBuffer.OfRef<T> sb = null; PermitStatus permitStatus; while ((permitStatus = permitStatus()) != PermitStatus.NO_MORE) {     if (permitStatus == PermitStatus.MAYBE_MORE) {         // Optimistically traverse elements up to a threshold of chunkSize         if (sb == null)  sb = new ArrayBuffer.OfRef<>(chunkSize);         else  sb.reset();         long permitsRequested = 0;         do { } while (s.tryAdvance(sb) && ++permitsRequested < chunkSize);         if (permitsRequested == 0)  return;         sb.forEach(action, acquirePermits(permitsRequested));     }     else {         // Must be UNLIMITED; let 'er rip         s.forEachRemaining(action);         return;     } }        }

所以现在有一个实例字段

chunkSize

((skip + limit) /AbstractTask.LEAF_TARGET) +1

CHUNK_SIZE

chunkSize

5

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