java8.util.VectorSpliterator Maven / Gradle / Ivy
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package java8.util;
import java.util.AbstractList;
import java.util.Comparator;
import java.util.ConcurrentModificationException;
import java.util.Vector;
import java8.util.Spliterator;
import java8.util.function.Consumer;
/** Similar to ArrayListSpliterator */
final class VectorSpliterator implements Spliterator {
// CVS rev. 1.46
private final Vector list;
private Object[] array;
private int index; // current index, modified on advance/split
private int fence; // -1 until used; then one past last index
private int expectedModCount; // initialized when fence set
/** Create new spliterator covering the given range */
private VectorSpliterator(Vector list, Object[] array, int origin, int fence,
int expectedModCount) {
this.list = list;
this.array = array;
this.index = origin;
this.fence = fence;
this.expectedModCount = expectedModCount;
}
static Spliterator spliterator(Vector vec) {
return new VectorSpliterator(vec, null, 0, -1, 0);
}
private int getFence() { // initialize on first use
int hi;
if ((hi = fence) < 0) {
synchronized (list) {
array = getData(list);
expectedModCount = getModCount(list);
hi = fence = getSize(list);
}
}
return hi;
}
@Override
public Spliterator trySplit() {
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
return (lo >= mid) ? null :
new VectorSpliterator(list, array, lo, index = mid,
expectedModCount);
}
@Override
@SuppressWarnings("unchecked")
public boolean tryAdvance(Consumer super E> action) {
Objects.requireNonNull(action);
int i;
if (getFence() > (i = index)) {
index = i + 1;
action.accept((E) array[i]);
if (expectedModCount != getModCount(list)) {
throw new ConcurrentModificationException();
}
return true;
}
return false;
}
@Override
@SuppressWarnings("unchecked")
public void forEachRemaining(Consumer super E> action) {
Objects.requireNonNull(action);
int hi = getFence();
Object[] a = array;
int i;
for (i = index, index = hi; i < hi; i++) {
action.accept((E) a[i]);
}
if (getModCount(list) != expectedModCount) {
throw new ConcurrentModificationException();
}
}
@Override
public long estimateSize() {
return getFence() - index;
}
@Override
public int characteristics() {
return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
}
@Override
public Comparator super E> getComparator() {
return Spliterators.getComparator(this);
}
@Override
public long getExactSizeIfKnown() {
return Spliterators.getExactSizeIfKnown(this);
}
@Override
public boolean hasCharacteristics(int characteristics) {
return Spliterators.hasCharacteristics(this, characteristics);
}
private static int getSize(Vector lst) {
return U.getInt(lst, SIZE_OFF);
}
private static int getModCount(Vector lst) {
return U.getInt(lst, MODCOUNT_OFF);
}
private static Object[] getData(Vector lst) {
return (Object[]) U.getObject(lst, DATA_OFF);
}
// Unsafe mechanics
private static final sun.misc.Unsafe U = UnsafeAccess.unsafe;
private static final long SIZE_OFF;
private static final long MODCOUNT_OFF;
private static final long DATA_OFF;
static {
try {
MODCOUNT_OFF = U.objectFieldOffset(AbstractList.class
.getDeclaredField("modCount"));
SIZE_OFF = U.objectFieldOffset(Vector.class
.getDeclaredField("elementCount"));
DATA_OFF = U.objectFieldOffset(Vector.class
.getDeclaredField("elementData"));
} catch (Exception e) {
throw new Error(e);
}
}
}
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