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*/ |
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package java.util; |
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import java.io.Serializable; |
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import java.util.function.Consumer; |
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import java.util.stream.Stream; |
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/** |
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* Resizable-array implementation of the {@link Deque} interface. Array |
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* |
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* @author Josh Bloch and Doug Lea |
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* @since 1.6 |
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* @param <E> the type of elements held in this collection |
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* @param <E> the type of elements held in this deque |
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*/ |
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public class ArrayDeque<E> extends AbstractCollection<E> |
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implements Deque<E>, Cloneable, Serializable |
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initialCapacity |= (initialCapacity >>> 16); |
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initialCapacity++; |
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|
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if (initialCapacity < 0) // Too many elements, must back off |
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initialCapacity >>>= 1;// Good luck allocating 2 ^ 30 elements |
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if (initialCapacity < 0) // Too many elements, must back off |
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initialCapacity >>>= 1; // Good luck allocating 2^30 elements |
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} |
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elements = new Object[initialCapacity]; |
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} |
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} |
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public E pollFirst() { |
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int h = head; |
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final Object[] elements = this.elements; |
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final int h = head; |
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@SuppressWarnings("unchecked") |
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E result = (E) elements[h]; |
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// Element is null if deque empty |
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if (result == null) |
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return null; |
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elements[h] = null; // Must null out slot |
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head = (h + 1) & (elements.length - 1); |
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if (result != null) { |
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elements[h] = null; // Must null out slot |
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head = (h + 1) & (elements.length - 1); |
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} |
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return result; |
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} |
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|
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public E pollLast() { |
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int t = (tail - 1) & (elements.length - 1); |
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final Object[] elements = this.elements; |
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final int t = (tail - 1) & (elements.length - 1); |
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@SuppressWarnings("unchecked") |
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E result = (E) elements[t]; |
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if (result == null) |
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return null; |
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elements[t] = null; |
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tail = t; |
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if (result != null) { |
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elements[t] = null; |
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tail = t; |
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} |
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return result; |
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} |
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|
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* @return {@code true} if the deque contained the specified element |
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*/ |
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public boolean removeFirstOccurrence(Object o) { |
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if (o == null) |
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return false; |
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int mask = elements.length - 1; |
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int i = head; |
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Object x; |
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while ( (x = elements[i]) != null) { |
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if (o.equals(x)) { |
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delete(i); |
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return true; |
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if (o != null) { |
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int mask = elements.length - 1; |
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int i = head; |
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for (Object x; (x = elements[i]) != null; i = (i + 1) & mask) { |
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if (o.equals(x)) { |
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delete(i); |
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return true; |
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} |
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} |
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i = (i + 1) & mask; |
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} |
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return false; |
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} |
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* @return {@code true} if the deque contained the specified element |
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*/ |
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public boolean removeLastOccurrence(Object o) { |
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if (o == null) |
347 |
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return false; |
348 |
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int mask = elements.length - 1; |
349 |
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int i = (tail - 1) & mask; |
350 |
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Object x; |
351 |
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while ( (x = elements[i]) != null) { |
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if (o.equals(x)) { |
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delete(i); |
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return true; |
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if (o != null) { |
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int mask = elements.length - 1; |
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int i = (tail - 1) & mask; |
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for (Object x; (x = elements[i]) != null; i = (i - 1) & mask) { |
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if (o.equals(x)) { |
351 |
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delete(i); |
352 |
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return true; |
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} |
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} |
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– |
i = (i - 1) & mask; |
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} |
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return false; |
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} |
608 |
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} |
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lastRet = -1; |
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} |
611 |
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|
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public void forEachRemaining(Consumer<? super E> action) { |
613 |
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Objects.requireNonNull(action); |
614 |
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Object[] a = elements; |
615 |
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int m = a.length - 1, f = fence, i = cursor; |
616 |
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cursor = f; |
617 |
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while (i != f) { |
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@SuppressWarnings("unchecked") E e = (E)a[i]; |
619 |
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i = (i + 1) & m; |
620 |
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if (e == null) |
621 |
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throw new ConcurrentModificationException(); |
622 |
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action.accept(e); |
623 |
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} |
624 |
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} |
625 |
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} |
626 |
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627 |
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/** |
670 |
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* @return {@code true} if this deque contains the specified element |
671 |
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*/ |
672 |
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public boolean contains(Object o) { |
673 |
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if (o == null) |
674 |
< |
return false; |
675 |
< |
int mask = elements.length - 1; |
676 |
< |
int i = head; |
677 |
< |
Object x; |
678 |
< |
while ( (x = elements[i]) != null) { |
679 |
< |
if (o.equals(x)) |
668 |
< |
return true; |
669 |
< |
i = (i + 1) & mask; |
673 |
> |
if (o != null) { |
674 |
> |
int mask = elements.length - 1; |
675 |
> |
int i = head; |
676 |
> |
for (Object x; (x = elements[i]) != null; i = (i + 1) & mask) { |
677 |
> |
if (o.equals(x)) |
678 |
> |
return true; |
679 |
> |
} |
680 |
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} |
681 |
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return false; |
682 |
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} |
762 |
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* The following code can be used to dump the deque into a newly |
763 |
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* allocated array of {@code String}: |
764 |
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* |
765 |
< |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
765 |
> |
* <pre> {@code String[] y = x.toArray(new String[0]);}</pre> |
766 |
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* |
767 |
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* Note that {@code toArray(new Object[0])} is identical in function to |
768 |
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* {@code toArray()}. |
820 |
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/** |
821 |
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* Saves this deque to a stream (that is, serializes it). |
822 |
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* |
823 |
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* @param s the stream |
824 |
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* @throws java.io.IOException if an I/O error occurs |
825 |
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* @serialData The current size ({@code int}) of the deque, |
826 |
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* followed by all of its elements (each an object reference) in |
827 |
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* first-to-last order. |
841 |
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|
842 |
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/** |
843 |
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* Reconstitutes this deque from a stream (that is, deserializes it). |
844 |
+ |
* @param s the stream |
845 |
+ |
* @throws ClassNotFoundException if the class of a serialized object |
846 |
+ |
* could not be found |
847 |
+ |
* @throws java.io.IOException if an I/O error occurs |
848 |
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*/ |
849 |
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private void readObject(java.io.ObjectInputStream s) |
850 |
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throws java.io.IOException, ClassNotFoundException { |
861 |
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elements[i] = s.readObject(); |
862 |
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} |
863 |
|
|
864 |
+ |
/** |
865 |
+ |
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> |
866 |
+ |
* and <em>fail-fast</em> {@link Spliterator} over the elements in this |
867 |
+ |
* deque. |
868 |
+ |
* |
869 |
+ |
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, |
870 |
+ |
* {@link Spliterator#SUBSIZED}, {@link Spliterator#ORDERED}, and |
871 |
+ |
* {@link Spliterator#NONNULL}. Overriding implementations should document |
872 |
+ |
* the reporting of additional characteristic values. |
873 |
+ |
* |
874 |
+ |
* @return a {@code Spliterator} over the elements in this deque |
875 |
+ |
* @since 1.8 |
876 |
+ |
*/ |
877 |
|
public Spliterator<E> spliterator() { |
878 |
< |
return new DeqSpliterator<E>(this, -1, -1); |
878 |
> |
return new DeqSpliterator<>(this, -1, -1); |
879 |
|
} |
880 |
|
|
881 |
|
static final class DeqSpliterator<E> implements Spliterator<E> { |
930 |
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throw new NullPointerException(); |
931 |
|
Object[] a = deq.elements; |
932 |
|
int m = a.length - 1, f = getFence(), i = index; |
933 |
< |
if (i != fence) { |
933 |
> |
if (i != f) { |
934 |
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@SuppressWarnings("unchecked") E e = (E)a[i]; |
935 |
|
index = (i + 1) & m; |
936 |
|
if (e == null) |