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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 1.51 by jsr166, Wed Feb 20 12:39:06 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	+	import java.util.stream.Streams;
11
12		/**
13		* Resizable-array implementation of the {@link Deque} interface.  Array
#	Line 53 | Line 57 | package java.util;
57		* @param <E> the type of elements held in this collection
58		*/
59		public class ArrayDeque<E> extends AbstractCollection<E>
60	<	implements Deque<E>, Cloneable, java.io.Serializable
60	>	implements Deque<E>, Cloneable, Serializable
61		{
62		/**
63		* The array in which the elements of the deque are stored.
#	Line 65 | Line 69 | public class ArrayDeque<E> extends Abstr
69		* other.  We also guarantee that all array cells not holding
70		* deque elements are always null.
71		*/
72	<	private transient Object[] elements;
72	>	transient Object[] elements; // non-private to simplify nested class access
73
74		/**
75		* The index of the element at the head of the deque (which is the
76		* element that would be removed by remove() or pop()); or an
77		* arbitrary number equal to tail if the deque is empty.
78		*/
79	<	private transient int head;
79	>	transient int head;
80
81		/**
82		* The index at which the next element would be added to the tail
83		* of the deque (via addLast(E), add(E), or push(E)).
84		*/
85	<	private transient int tail;
85	>	transient int tail;
86
87		/**
88		* The minimum capacity that we'll use for a newly created deque.
#	Line 133 | Line 137 | public class ArrayDeque<E> extends Abstr
137		}
138
139		/**
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	–	/**
140		* Constructs an empty array deque with an initial capacity
141		* sufficient to hold 16 elements.
142		*/
#	Line 694 | Line 680 | public class ArrayDeque<E> extends Abstr
680		* Returns {@code true} if this deque contained the specified element
681		* (or equivalently, if this deque changed as a result of the call).
682		*
683	<	* <p>This method is equivalent to {@link #removeFirstOccurrence}.
683	>	* <p>This method is equivalent to {@link #removeFirstOccurrence(Object)}.
684		*
685		* @param o element to be removed from this deque, if present
686		* @return {@code true} if this deque contained the specified element
#	Line 735 | Line 721 | public class ArrayDeque<E> extends Abstr
721		* @return an array containing all of the elements in this deque
722		*/
723		public Object[] toArray() {
724	<	return copyElements(new Object[size()]);
724	>	final int head = this.head;
725	>	final int tail = this.tail;
726	>	boolean wrap = (tail < head);
727	>	int end = wrap ? tail + elements.length : tail;
728	>	Object[] a = Arrays.copyOfRange(elements, head, end);
729	>	if (wrap)
730	>	System.arraycopy(elements, 0, a, elements.length - head, tail);
731	>	return a;
732		}
733
734		/**
#	Line 776 | Line 769 | public class ArrayDeque<E> extends Abstr
769		*/
770		@SuppressWarnings("unchecked")
771		public <T> T[] toArray(T[] a) {
772	<	int size = size();
773	<	if (a.length < size)
774	<	a = (T[])java.lang.reflect.Array.newInstance(
775	<	a.getClass().getComponentType(), size);
776	<	copyElements(a);
777	<	if (a.length > size)
778	<	a[size] = null;
772	>	final int head = this.head;
773	>	final int tail = this.tail;
774	>	boolean wrap = (tail < head);
775	>	int size = (tail - head) + (wrap ? elements.length : 0);
776	>	int firstLeg = size - (wrap ? tail : 0);
777	>	int len = a.length;
778	>	if (size > len) {
779	>	a = (T[]) Arrays.copyOfRange(elements, head, head + size,
780	>	a.getClass());
781	>	} else {
782	>	System.arraycopy(elements, head, a, 0, firstLeg);
783	>	if (size < len)
784	>	a[size] = null;
785	>	}
786	>	if (wrap)
787	>	System.arraycopy(elements, 0, a, firstLeg, tail);
788		return a;
789		}
790
#	Line 843 | Line 845 | public class ArrayDeque<E> extends Abstr
845		for (int i = 0; i < size; i++)
846		elements[i] = s.readObject();
847		}
848	+
849	+	Spliterator<E> spliterator() {
850	+	return new DeqSpliterator<E>(this, -1, -1);
851	+	}
852	+
853	+	public Stream<E> stream() {
854	+	return Streams.stream(spliterator());
855	+	}
856	+
857	+	public Stream<E> parallelStream() {
858	+	return Streams.parallelStream(spliterator());
859	+	}
860	+
861	+	static final class DeqSpliterator<E> implements Spliterator<E> {
862	+	private final ArrayDeque<E> deq;
863	+	private int fence;  // -1 until first use
864	+	private int index;  // current index, modified on traverse/split
865	+
866	+	/** Creates new spliterator covering the given array and range */
867	+	DeqSpliterator(ArrayDeque<E> deq, int origin, int fence) {
868	+	this.deq = deq;
869	+	this.index = origin;
870	+	this.fence = fence;
871	+	}
872	+
873	+	private int getFence() { // force initialization
874	+	int t;
875	+	if ((t = fence) < 0) {
876	+	t = fence = deq.tail;
877	+	index = deq.head;
878	+	}
879	+	return t;
880	+	}
881	+
882	+	public DeqSpliterator<E> trySplit() {
883	+	int t = getFence(), h = index, n = deq.elements.length;
884	+	if (h != t && ((h + 1) & (n - 1)) != t) {
885	+	if (h > t)
886	+	t += n;
887	+	int m = ((h + t) >>> 1) & (n - 1);
888	+	return new DeqSpliterator<>(deq, h, index = m);
889	+	}
890	+	return null;
891	+	}
892	+
893	+	public void forEach(Consumer<? super E> consumer) {
894	+	if (consumer == null)
895	+	throw new NullPointerException();
896	+	Object[] a = deq.elements;
897	+	int m = a.length - 1, f = getFence(), i = index;
898	+	index = f;
899	+	while (i != f) {
900	+	@SuppressWarnings("unchecked") E e = (E)a[i];
901	+	i = (i + 1) & m;
902	+	if (e == null)
903	+	throw new ConcurrentModificationException();
904	+	consumer.accept(e);
905	+	}
906	+	}
907	+
908	+	public boolean tryAdvance(Consumer<? super E> consumer) {
909	+	if (consumer == null)
910	+	throw new NullPointerException();
911	+	Object[] a = deq.elements;
912	+	int m = a.length - 1, f = getFence(), i = index;
913	+	if (i != fence) {
914	+	@SuppressWarnings("unchecked") E e = (E)a[i];
915	+	index = (i + 1) & m;
916	+	if (e == null)
917	+	throw new ConcurrentModificationException();
918	+	consumer.accept(e);
919	+	return true;
920	+	}
921	+	return false;
922	+	}
923	+
924	+	public long estimateSize() {
925	+	int n = getFence() - index;
926	+	if (n < 0)
927	+	n += deq.elements.length;
928	+	return (long) n;
929	+	}
930	+
931	+	@Override
932	+	public int characteristics() {
933	+	return Spliterator.ORDERED | Spliterator.SIZED |
934	+	Spliterator.NONNULL | Spliterator.SUBSIZED;
935	+	}
936	+	}
937	+
938		}

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