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root/jsr166/jsr166/src/main/java/util/ArrayDeque.java

Comparing jsr166/src/main/java/util/ArrayDeque.java (file contents):
Revision 1.40 by jsr166, Sun Feb 26 22:43:03 2012 UTC vs.
Revision 1.55 by jsr166, Thu May 2 06:02:17 2013 UTC

#	Line 4 | Line 4
4		*/
5
6		package java.util;
7	+	import java.io.Serializable;
8	+	import java.util.function.Consumer;
9	+	import java.util.stream.Stream;
10
11		/**
12		* Resizable-array implementation of the {@link Deque} interface.  Array
#	Line 53 | Line 56 | package java.util;
56		* @param <E> the type of elements held in this collection
57		*/
58		public class ArrayDeque<E> extends AbstractCollection<E>
59	<	implements Deque<E>, Cloneable, java.io.Serializable
59	>	implements Deque<E>, Cloneable, Serializable
60		{
61		/**
62		* The array in which the elements of the deque are stored.
#	Line 65 | Line 68 | public class ArrayDeque<E> extends Abstr
68		* other.  We also guarantee that all array cells not holding
69		* deque elements are always null.
70		*/
71	<	private transient Object[] elements;
71	>	transient Object[] elements; // non-private to simplify nested class access
72
73		/**
74		* The index of the element at the head of the deque (which is the
75		* element that would be removed by remove() or pop()); or an
76		* arbitrary number equal to tail if the deque is empty.
77		*/
78	<	private transient int head;
78	>	transient int head;
79
80		/**
81		* The index at which the next element would be added to the tail
82		* of the deque (via addLast(E), add(E), or push(E)).
83		*/
84	<	private transient int tail;
84	>	transient int tail;
85
86		/**
87		* The minimum capacity that we'll use for a newly created deque.
#	Line 133 | Line 136 | public class ArrayDeque<E> extends Abstr
136		}
137
138		/**
136	–	* Copies the elements from our element array into the specified array,
137	–	* in order (from first to last element in the deque).  It is assumed
138	–	* that the array is large enough to hold all elements in the deque.
139	–	*
140	–	* @return its argument
141	–	*/
142	–	private <T> T[] copyElements(T[] a) {
143	–	if (head < tail) {
144	–	System.arraycopy(elements, head, a, 0, size());
145	–	} else if (head > tail) {
146	–	int headPortionLen = elements.length - head;
147	–	System.arraycopy(elements, head, a, 0, headPortionLen);
148	–	System.arraycopy(elements, 0, a, headPortionLen, tail);
149	–	}
150	–	return a;
151	–	}
152	–
153	–	/**
139		* Constructs an empty array deque with an initial capacity
140		* sufficient to hold 16 elements.
141		*/
#	Line 627 | Line 612 | public class ArrayDeque<E> extends Abstr
612		}
613		}
614
615	+	/**
616	+	* This class is nearly a mirror-image of DeqIterator, using tail
617	+	* instead of head for initial cursor, and head instead of tail
618	+	* for fence.
619	+	*/
620		private class DescendingIterator implements Iterator<E> {
631	–	/*
632	–	* This class is nearly a mirror-image of DeqIterator, using
633	–	* tail instead of head for initial cursor, and head instead of
634	–	* tail for fence.
635	–	*/
621		private int cursor = tail;
622		private int fence = head;
623		private int lastRet = -1;
#	Line 694 | Line 679 | public class ArrayDeque<E> extends Abstr
679		* Returns {@code true} if this deque contained the specified element
680		* (or equivalently, if this deque changed as a result of the call).
681		*
682	<	* <p>This method is equivalent to {@link #removeFirstOccurrence}.
682	>	* <p>This method is equivalent to {@link #removeFirstOccurrence(Object)}.
683		*
684		* @param o element to be removed from this deque, if present
685		* @return {@code true} if this deque contained the specified element
#	Line 735 | Line 720 | public class ArrayDeque<E> extends Abstr
720		* @return an array containing all of the elements in this deque
721		*/
722		public Object[] toArray() {
723	<	return copyElements(new Object[size()]);
723	>	final int head = this.head;
724	>	final int tail = this.tail;
725	>	boolean wrap = (tail < head);
726	>	int end = wrap ? tail + elements.length : tail;
727	>	Object[] a = Arrays.copyOfRange(elements, head, end);
728	>	if (wrap)
729	>	System.arraycopy(elements, 0, a, elements.length - head, tail);
730	>	return a;
731		}
732
733		/**
#	Line 776 | Line 768 | public class ArrayDeque<E> extends Abstr
768		*/
769		@SuppressWarnings("unchecked")
770		public <T> T[] toArray(T[] a) {
771	<	int size = size();
772	<	if (a.length < size)
773	<	a = (T[])java.lang.reflect.Array.newInstance(
774	<	a.getClass().getComponentType(), size);
775	<	copyElements(a);
776	<	if (a.length > size)
777	<	a[size] = null;
771	>	final int head = this.head;
772	>	final int tail = this.tail;
773	>	boolean wrap = (tail < head);
774	>	int size = (tail - head) + (wrap ? elements.length : 0);
775	>	int firstLeg = size - (wrap ? tail : 0);
776	>	int len = a.length;
777	>	if (size > len) {
778	>	a = (T[]) Arrays.copyOfRange(elements, head, head + size,
779	>	a.getClass());
780	>	} else {
781	>	System.arraycopy(elements, head, a, 0, firstLeg);
782	>	if (size < len)
783	>	a[size] = null;
784	>	}
785	>	if (wrap)
786	>	System.arraycopy(elements, 0, a, firstLeg, tail);
787		return a;
788		}
789
#	Line 843 | Line 844 | public class ArrayDeque<E> extends Abstr
844		for (int i = 0; i < size; i++)
845		elements[i] = s.readObject();
846		}
847	+
848	+	public Spliterator<E> spliterator() {
849	+	return new DeqSpliterator<E>(this, -1, -1);
850	+	}
851	+
852	+	static final class DeqSpliterator<E> implements Spliterator<E> {
853	+	private final ArrayDeque<E> deq;
854	+	private int fence;  // -1 until first use
855	+	private int index;  // current index, modified on traverse/split
856	+
857	+	/** Creates new spliterator covering the given array and range */
858	+	DeqSpliterator(ArrayDeque<E> deq, int origin, int fence) {
859	+	this.deq = deq;
860	+	this.index = origin;
861	+	this.fence = fence;
862	+	}
863	+
864	+	private int getFence() { // force initialization
865	+	int t;
866	+	if ((t = fence) < 0) {
867	+	t = fence = deq.tail;
868	+	index = deq.head;
869	+	}
870	+	return t;
871	+	}
872	+
873	+	public Spliterator<E> trySplit() {
874	+	int t = getFence(), h = index, n = deq.elements.length;
875	+	if (h != t && ((h + 1) & (n - 1)) != t) {
876	+	if (h > t)
877	+	t += n;
878	+	int m = ((h + t) >>> 1) & (n - 1);
879	+	return new DeqSpliterator<>(deq, h, index = m);
880	+	}
881	+	return null;
882	+	}
883	+
884	+	public void forEachRemaining(Consumer<? super E> consumer) {
885	+	if (consumer == null)
886	+	throw new NullPointerException();
887	+	Object[] a = deq.elements;
888	+	int m = a.length - 1, f = getFence(), i = index;
889	+	index = f;
890	+	while (i != f) {
891	+	@SuppressWarnings("unchecked") E e = (E)a[i];
892	+	i = (i + 1) & m;
893	+	if (e == null)
894	+	throw new ConcurrentModificationException();
895	+	consumer.accept(e);
896	+	}
897	+	}
898	+
899	+	public boolean tryAdvance(Consumer<? super E> consumer) {
900	+	if (consumer == null)
901	+	throw new NullPointerException();
902	+	Object[] a = deq.elements;
903	+	int m = a.length - 1, f = getFence(), i = index;
904	+	if (i != fence) {
905	+	@SuppressWarnings("unchecked") E e = (E)a[i];
906	+	index = (i + 1) & m;
907	+	if (e == null)
908	+	throw new ConcurrentModificationException();
909	+	consumer.accept(e);
910	+	return true;
911	+	}
912	+	return false;
913	+	}
914	+
915	+	public long estimateSize() {
916	+	int n = getFence() - index;
917	+	if (n < 0)
918	+	n += deq.elements.length;
919	+	return (long) n;
920	+	}
921	+
922	+	@Override
923	+	public int characteristics() {
924	+	return Spliterator.ORDERED | Spliterator.SIZED |
925	+	Spliterator.NONNULL | Spliterator.SUBSIZED;
926	+	}
927	+	}
928	+
929		}

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