ViewVC Help

View File | Revision Log | Show Annotations | Download File | Root Listing

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

Comparing jsr166/src/main/java/util/ArrayDeque.java (file contents):
Revision 1.47 by dl, Sun Feb 17 23:36:16 2013 UTC vs.
Revision 1.65 by jsr166, Sat Feb 28 20:35:47 2015 UTC

#	Line 4 | Line 4
4		*/
5
6		package java.util;
7	+
8		import java.io.Serializable;
9		import java.util.function.Consumer;
9	–	import java.util.stream.Stream;
10	–	import java.util.stream.Streams;
10
11		/**
12		* Resizable-array implementation of the {@link Deque} interface.  Array
#	Line 19 | Line 18 | import java.util.stream.Streams;
18		* when used as a queue.
19		*
20		* <p>Most {@code ArrayDeque} operations run in amortized constant time.
21	<	* Exceptions include {@link #remove(Object) remove}, {@link
22	<	* #removeFirstOccurrence removeFirstOccurrence}, {@link #removeLastOccurrence
23	<	* removeLastOccurrence}, {@link #contains contains}, {@link #iterator
24	<	* iterator.remove()}, and the bulk operations, all of which run in linear
25	<	* time.
21	>	* Exceptions include
22	>	* {@link #remove(Object) remove},
23	>	* {@link #removeFirstOccurrence removeFirstOccurrence},
24	>	* {@link #removeLastOccurrence removeLastOccurrence},
25	>	* {@link #contains contains},
26	>	* {@link #iterator iterator.remove()},
27	>	* and the bulk operations, all of which run in linear time.
28		*
29	<	* <p>The iterators returned by this class's {@code iterator} method are
30	<	* <i>fail-fast</i>: If the deque is modified at any time after the iterator
31	<	* is created, in any way except through the iterator's own {@code remove}
32	<	* method, the iterator will generally throw a {@link
29	>	* <p>The iterators returned by this class's {@link #iterator() iterator}
30	>	* method are <em>fail-fast</em>: If the deque is modified at any time after
31	>	* the iterator is created, in any way except through the iterator's own
32	>	* {@code remove} method, the iterator will generally throw a {@link
33		* ConcurrentModificationException}.  Thus, in the face of concurrent
34		* modification, the iterator fails quickly and cleanly, rather than risking
35		* arbitrary, non-deterministic behavior at an undetermined time in the
#	Line 52 | Line 53 | import java.util.stream.Streams;
53		*
54		* @author  Josh Bloch and Doug Lea
55		* @since   1.6
56	<	* @param <E> the type of elements held in this collection
56	>	* @param <E> the type of elements held in this deque
57		*/
58		public class ArrayDeque<E> extends AbstractCollection<E>
59		implements Deque<E>, Cloneable, Serializable
#	Line 135 | Line 136 | public class ArrayDeque<E> extends Abstr
136		}
137
138		/**
138	–	* Copies the elements from our element array into the specified array,
139	–	* in order (from first to last element in the deque).  It is assumed
140	–	* that the array is large enough to hold all elements in the deque.
141	–	*
142	–	* @return its argument
143	–	*/
144	–	private <T> T[] copyElements(T[] a) {
145	–	if (head < tail) {
146	–	System.arraycopy(elements, head, a, 0, size());
147	–	} else if (head > tail) {
148	–	int headPortionLen = elements.length - head;
149	–	System.arraycopy(elements, head, a, 0, headPortionLen);
150	–	System.arraycopy(elements, 0, a, headPortionLen, tail);
151	–	}
152	–	return a;
153	–	}
154	–
155	–	/**
139		* Constructs an empty array deque with an initial capacity
140		* sufficient to hold 16 elements.
141		*/
#	Line 268 | Line 251 | public class ArrayDeque<E> extends Abstr
251		@SuppressWarnings("unchecked")
252		E result = (E) elements[h];
253		// Element is null if deque empty
254	<	if (result == null)
255	<	return null;
256	<	elements[h] = null;     // Must null out slot
257	<	head = (h + 1) & (elements.length - 1);
254	>	if (result != null) {
255	>	elements[h] = null; // Must null out slot
256	>	head = (h + 1) & (elements.length - 1);
257	>	}
258		return result;
259		}
260
#	Line 279 | Line 262 | public class ArrayDeque<E> extends Abstr
262		int t = (tail - 1) & (elements.length - 1);
263		@SuppressWarnings("unchecked")
264		E result = (E) elements[t];
265	<	if (result == null)
266	<	return null;
267	<	elements[t] = null;
268	<	tail = t;
265	>	if (result != null) {
266	>	elements[t] = null;
267	>	tail = t;
268	>	}
269		return result;
270		}
271
#	Line 332 | Line 315 | public class ArrayDeque<E> extends Abstr
315		* @return {@code true} if the deque contained the specified element
316		*/
317		public boolean removeFirstOccurrence(Object o) {
318	<	if (o == null)
319	<	return false;
320	<	int mask = elements.length - 1;
321	<	int i = head;
322	<	Object x;
323	<	while ( (x = elements[i]) != null) {
324	<	if (o.equals(x)) {
325	<	delete(i);
343	<	return true;
318	>	if (o != null) {
319	>	int mask = elements.length - 1;
320	>	int i = head;
321	>	for (Object x; (x = elements[i]) != null; i = (i + 1) & mask) {
322	>	if (o.equals(x)) {
323	>	delete(i);
324	>	return true;
325	>	}
326		}
345	–	i = (i + 1) & mask;
327		}
328		return false;
329		}
#	Line 360 | Line 341 | public class ArrayDeque<E> extends Abstr
341		* @return {@code true} if the deque contained the specified element
342		*/
343		public boolean removeLastOccurrence(Object o) {
344	<	if (o == null)
345	<	return false;
346	<	int mask = elements.length - 1;
347	<	int i = (tail - 1) & mask;
348	<	Object x;
349	<	while ( (x = elements[i]) != null) {
350	<	if (o.equals(x)) {
351	<	delete(i);
371	<	return true;
344	>	if (o != null) {
345	>	int mask = elements.length - 1;
346	>	int i = (tail - 1) & mask;
347	>	for (Object x; (x = elements[i]) != null; i = (i - 1) & mask) {
348	>	if (o.equals(x)) {
349	>	delete(i);
350	>	return true;
351	>	}
352		}
373	–	i = (i - 1) & mask;
353		}
354		return false;
355		}
#	Line 629 | Line 608 | public class ArrayDeque<E> extends Abstr
608		}
609		}
610
611	+	/**
612	+	* This class is nearly a mirror-image of DeqIterator, using tail
613	+	* instead of head for initial cursor, and head instead of tail
614	+	* for fence.
615	+	*/
616		private class DescendingIterator implements Iterator<E> {
633	–	/*
634	–	* This class is nearly a mirror-image of DeqIterator, using
635	–	* tail instead of head for initial cursor, and head instead of
636	–	* tail for fence.
637	–	*/
617		private int cursor = tail;
618		private int fence = head;
619		private int lastRet = -1;
#	Line 675 | Line 654 | public class ArrayDeque<E> extends Abstr
654		* @return {@code true} if this deque contains the specified element
655		*/
656		public boolean contains(Object o) {
657	<	if (o == null)
658	<	return false;
659	<	int mask = elements.length - 1;
660	<	int i = head;
661	<	Object x;
662	<	while ( (x = elements[i]) != null) {
663	<	if (o.equals(x))
685	<	return true;
686	<	i = (i + 1) & mask;
657	>	if (o != null) {
658	>	int mask = elements.length - 1;
659	>	int i = head;
660	>	for (Object x; (x = elements[i]) != null; i = (i + 1) & mask) {
661	>	if (o.equals(x))
662	>	return true;
663	>	}
664		}
665		return false;
666		}
#	Line 737 | Line 714 | public class ArrayDeque<E> extends Abstr
714		* @return an array containing all of the elements in this deque
715		*/
716		public Object[] toArray() {
717	<	return copyElements(new Object[size()]);
717	>	final int head = this.head;
718	>	final int tail = this.tail;
719	>	boolean wrap = (tail < head);
720	>	int end = wrap ? tail + elements.length : tail;
721	>	Object[] a = Arrays.copyOfRange(elements, head, end);
722	>	if (wrap)
723	>	System.arraycopy(elements, 0, a, elements.length - head, tail);
724	>	return a;
725		}
726
727		/**
#	Line 762 | Line 746 | public class ArrayDeque<E> extends Abstr
746		* The following code can be used to dump the deque into a newly
747		* allocated array of {@code String}:
748		*
749	<	*  <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
749	>	* <pre> {@code String[] y = x.toArray(new String[0]);}</pre>
750		*
751		* Note that {@code toArray(new Object[0])} is identical in function to
752		* {@code toArray()}.
#	Line 778 | Line 762 | public class ArrayDeque<E> extends Abstr
762		*/
763		@SuppressWarnings("unchecked")
764		public <T> T[] toArray(T[] a) {
765	<	int size = size();
766	<	if (a.length < size)
767	<	a = (T[])java.lang.reflect.Array.newInstance(
768	<	a.getClass().getComponentType(), size);
769	<	copyElements(a);
770	<	if (a.length > size)
771	<	a[size] = null;
765	>	final int head = this.head;
766	>	final int tail = this.tail;
767	>	boolean wrap = (tail < head);
768	>	int size = (tail - head) + (wrap ? elements.length : 0);
769	>	int firstLeg = size - (wrap ? tail : 0);
770	>	int len = a.length;
771	>	if (size > len) {
772	>	a = (T[]) Arrays.copyOfRange(elements, head, head + size,
773	>	a.getClass());
774	>	} else {
775	>	System.arraycopy(elements, head, a, 0, firstLeg);
776	>	if (size < len)
777	>	a[size] = null;
778	>	}
779	>	if (wrap)
780	>	System.arraycopy(elements, 0, a, firstLeg, tail);
781		return a;
782		}
783
#	Line 811 | Line 804 | public class ArrayDeque<E> extends Abstr
804		/**
805		* Saves this deque to a stream (that is, serializes it).
806		*
807	+	* @param s the stream
808	+	* @throws java.io.IOException if an I/O error occurs
809		* @serialData The current size ({@code int}) of the deque,
810		* followed by all of its elements (each an object reference) in
811		* first-to-last order.
#	Line 830 | Line 825 | public class ArrayDeque<E> extends Abstr
825
826		/**
827		* Reconstitutes this deque from a stream (that is, deserializes it).
828	+	* @param s the stream
829	+	* @throws ClassNotFoundException if the class of a serialized object
830	+	*         could not be found
831	+	* @throws java.io.IOException if an I/O error occurs
832		*/
833		private void readObject(java.io.ObjectInputStream s)
834		throws java.io.IOException, ClassNotFoundException {
#	Line 846 | Line 845 | public class ArrayDeque<E> extends Abstr
845		elements[i] = s.readObject();
846		}
847
848	<	Spliterator<E> spliterator() {
848	>	public Spliterator<E> spliterator() {
849		return new DeqSpliterator<E>(this, -1, -1);
850		}
851
853	–	public Stream<E> stream() {
854	–	return Streams.stream(spliterator());
855	–	}
856	–
857	–	public Stream<E> parallelStream() {
858	–	return Streams.parallelStream(spliterator());
859	–	}
860	–
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	<	/** Create new spliterator covering the given array and range */
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;
#	Line 879 | Line 870 | public class ArrayDeque<E> extends Abstr
870		return t;
871		}
872
873	<	public DeqSpliterator<E> trySplit() {
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)
#	Line 890 | Line 881 | public class ArrayDeque<E> extends Abstr
881		return null;
882		}
883
884	<	public void forEach(Consumer<? super E> consumer) {
884	>	public void forEachRemaining(Consumer<? super E> consumer) {
885		if (consumer == null)
886		throw new NullPointerException();
887		Object[] a = deq.elements;
#	Line 910 | Line 901 | public class ArrayDeque<E> extends Abstr
901		throw new NullPointerException();
902		Object[] a = deq.elements;
903		int m = a.length - 1, f = getFence(), i = index;
904	<	if (i != fence) {
904	>	if (i != f) {
905		@SuppressWarnings("unchecked") E e = (E)a[i];
906		index = (i + 1) & m;
907		if (e == null)
#	Line 930 | Line 921 | public class ArrayDeque<E> extends Abstr
921
922		@Override
923		public int characteristics() {
924	<	return Spliterator.ORDERED | Spliterator.SIZED |
924	>	return Spliterator.ORDERED | Spliterator.SIZED |
925		Spliterator.NONNULL | Spliterator.SUBSIZED;
926		}
927		}

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines