Java Spliterator.getComparator方法代碼示例

import java.util.Spliterator; //導入方法依賴的package包/類
private static void assertSpliterator(Spliterator<?> s) {
    if (s.hasCharacteristics(Spliterator.SUBSIZED)) {
        assertTrue(s.hasCharacteristics(Spliterator.SIZED));
    }
    if (s.hasCharacteristics(Spliterator.SIZED)) {
        assertTrue(s.estimateSize() != Long.MAX_VALUE);
        assertTrue(s.getExactSizeIfKnown() >= 0);
    }
    try {
        s.getComparator();
        assertTrue(s.hasCharacteristics(Spliterator.SORTED));
    } catch (IllegalStateException e) {
        assertFalse(s.hasCharacteristics(Spliterator.SORTED));
    }
}
 

import java.util.Spliterator; //導入方法依賴的package包/類
void assertISEComparator(Spliterator<?> s) {
    boolean caught = false;
    try {
        s.getComparator();
    }
    catch (IllegalStateException e) {
        caught = true;
    }
    assertTrue(caught, "Throwing IllegalStateException");
}
 

import java.util.Spliterator; //導入方法依賴的package包/類
/**
 * Spliterator.getComparator throws IllegalStateException iff the
 * spliterator does not report SORTED.
 */
public void testGetComparator_IllegalStateException() {
    Collection c = impl.emptyCollection();
    Spliterator s = c.spliterator();
    boolean reportsSorted = s.hasCharacteristics(Spliterator.SORTED);
    try {
        s.getComparator();
        assertTrue(reportsSorted);
    } catch (IllegalStateException ex) {
        assertFalse(reportsSorted);
    }
}
 

import java.util.Spliterator; //導入方法依賴的package包/類
/** Returns a {@code Spliterator} filtered by the specified predicate. */
static <T> Spliterator<T> filter(Spliterator<T> fromSpliterator, Predicate<? super T> predicate) {
  checkNotNull(fromSpliterator);
  checkNotNull(predicate);
  class Splitr implements Spliterator<T>, Consumer<T> {
    T holder = null;

    @Override
    public void accept(T t) {
      this.holder = t;
    }

    @Override
    public boolean tryAdvance(Consumer<? super T> action) {
      while (fromSpliterator.tryAdvance(this)) {
        try {
          if (predicate.test(holder)) {
            action.accept(holder);
            return true;
          }
        } finally {
          holder = null;
        }
      }
      return false;
    }

    @Override
    public Spliterator<T> trySplit() {
      Spliterator<T> fromSplit = fromSpliterator.trySplit();
      return (fromSplit == null) ? null : filter(fromSplit, predicate);
    }

    @Override
    public long estimateSize() {
      return fromSpliterator.estimateSize() / 2;
    }

    @Override
    public Comparator<? super T> getComparator() {
      return fromSpliterator.getComparator();
    }

    @Override
    public int characteristics() {
      return fromSpliterator.characteristics()
          & (Spliterator.DISTINCT
              | Spliterator.NONNULL
              | Spliterator.ORDERED
              | Spliterator.SORTED);
    }
  }
  return new Splitr();
}
 

import java.util.Spliterator; //導入方法依賴的package包/類
/**
 * Converts a spliterator characteristic bit set to stream flags.
 *
 * @implSpec
 * If the spliterator is naturally {@code SORTED} (the associated
 * {@code Comparator} is {@code null}) then the characteristic is converted
 * to the {@link #SORTED} flag, otherwise the characteristic is not
 * converted.
 *
 * @param spliterator the spliterator from which to obtain characteristic
 *        bit set.
 * @return the stream flags.
 */
static int fromCharacteristics(Spliterator<?> spliterator) {
    int characteristics = spliterator.characteristics();
    if ((characteristics & Spliterator.SORTED) != 0 && spliterator.getComparator() != null) {
        // Do not propagate the SORTED characteristic if it does not correspond
        // to a natural sort order
        return characteristics & SPLITERATOR_CHARACTERISTICS_MASK & ~Spliterator.SORTED;
    }
    else {
        return characteristics & SPLITERATOR_CHARACTERISTICS_MASK;
    }
}