4 |
|
*/ |
5 |
|
|
6 |
|
package java.util; |
7 |
+ |
import java.util.*; // for javadoc (till 6280605 is fixed) |
8 |
|
import java.io.*; |
9 |
|
|
10 |
|
/** |
203 |
|
|
204 |
|
/** |
205 |
|
* Inserts the specified element at the end of this deque. |
206 |
< |
* This method is equivalent to {@link #add} and {@link #push}. |
206 |
> |
* |
207 |
> |
* <p>This method is equivalent to {@link #add}. |
208 |
|
* |
209 |
|
* @param e the element to add |
210 |
|
* @throws NullPointerException if the specified element is null |
221 |
|
* Inserts the specified element at the front of this deque. |
222 |
|
* |
223 |
|
* @param e the element to add |
224 |
< |
* @return <tt>true</tt> (as per the spec for {@link Deque#offerFirst}) |
224 |
> |
* @return <tt>true</tt> (as specified by {@link Deque#offerFirst}) |
225 |
|
* @throws NullPointerException if the specified element is null |
226 |
|
*/ |
227 |
|
public boolean offerFirst(E e) { |
233 |
|
* Inserts the specified element at the end of this deque. |
234 |
|
* |
235 |
|
* @param e the element to add |
236 |
< |
* @return <tt>true</tt> (as per the spec for {@link Deque#offerLast}) |
236 |
> |
* @return <tt>true</tt> (as specified by {@link Deque#offerLast}) |
237 |
|
* @throws NullPointerException if the specified element is null |
238 |
|
*/ |
239 |
|
public boolean offerLast(E e) { |
373 |
|
* <p>This method is equivalent to {@link #addLast}. |
374 |
|
* |
375 |
|
* @param e the element to add |
376 |
< |
* @return <tt>true</tt> (as per the spec for {@link Collection#add}) |
376 |
> |
* @return <tt>true</tt> (as specified by {@link Collection#add}) |
377 |
|
* @throws NullPointerException if the specified element is null |
378 |
|
*/ |
379 |
|
public boolean add(E e) { |
387 |
|
* <p>This method is equivalent to {@link #offerLast}. |
388 |
|
* |
389 |
|
* @param e the element to add |
390 |
< |
* @return <tt>true</tt> (as per the spec for {@link Queue#offer}) |
390 |
> |
* @return <tt>true</tt> (as specified by {@link Queue#offer}) |
391 |
|
* @throws NullPointerException if the specified element is null |
392 |
|
*/ |
393 |
|
public boolean offer(E e) { |
396 |
|
|
397 |
|
/** |
398 |
|
* Retrieves and removes the head of the queue represented by this deque. |
399 |
< |
* This method differs from {@link #poll} only in that it throws an |
399 |
> |
* |
400 |
> |
* This method differs from {@link #poll poll} only in that it throws an |
401 |
|
* exception if this deque is empty. |
402 |
|
* |
403 |
|
* <p>This method is equivalent to {@link #removeFirst}. |
425 |
|
|
426 |
|
/** |
427 |
|
* Retrieves, but does not remove, the head of the queue represented by |
428 |
< |
* this deque. This method differs from {@link #peek} only in that it |
429 |
< |
* throws an exception if this deque is empty. |
428 |
> |
* this deque. This method differs from {@link #peek peek} only in |
429 |
> |
* that it throws an exception if this deque is empty. |
430 |
|
* |
431 |
|
* <p>This method is equivalent to {@link #getFirst}. |
432 |
|
* |
538 |
|
* order that elements would be dequeued (via successive calls to |
539 |
|
* {@link #remove} or popped (via successive calls to {@link #pop}). |
540 |
|
* |
541 |
< |
* @return an <tt>Iterator</tt> over the elements in this deque |
541 |
> |
* @return an iterator over the elements in this deque |
542 |
|
*/ |
543 |
|
public Iterator<E> iterator() { |
544 |
|
return new DeqIterator(); |
545 |
|
} |
546 |
|
|
547 |
+ |
public Iterator<E> descendingIterator() { |
548 |
+ |
return new DescendingIterator(); |
549 |
+ |
} |
550 |
+ |
|
551 |
|
private class DeqIterator implements Iterator<E> { |
552 |
|
/** |
553 |
|
* Index of element to be returned by subsequent call to next. |
586 |
|
public void remove() { |
587 |
|
if (lastRet < 0) |
588 |
|
throw new IllegalStateException(); |
589 |
< |
if (delete(lastRet)) |
590 |
< |
cursor--; |
589 |
> |
if (delete(lastRet)) // if left-shifted, undo increment in next() |
590 |
> |
cursor = (cursor - 1) & (elements.length - 1); |
591 |
|
lastRet = -1; |
592 |
|
fence = tail; |
593 |
|
} |
594 |
|
} |
595 |
|
|
596 |
+ |
|
597 |
+ |
private class DescendingIterator implements Iterator<E> { |
598 |
+ |
/* |
599 |
+ |
* This class is nearly a mirror-image of DeqIterator, using |
600 |
+ |
* (tail-1) instead of head for initial cursor, (head-1) |
601 |
+ |
* instead of tail for fence, and elements.length instead of -1 |
602 |
+ |
* for sentinel. It shares the same structure, but not many |
603 |
+ |
* actual lines of code. |
604 |
+ |
*/ |
605 |
+ |
private int cursor = (tail - 1) & (elements.length - 1); |
606 |
+ |
private int fence = (head - 1) & (elements.length - 1); |
607 |
+ |
private int lastRet = elements.length; |
608 |
+ |
|
609 |
+ |
public boolean hasNext() { |
610 |
+ |
return cursor != fence; |
611 |
+ |
} |
612 |
+ |
|
613 |
+ |
public E next() { |
614 |
+ |
E result; |
615 |
+ |
if (cursor == fence) |
616 |
+ |
throw new NoSuchElementException(); |
617 |
+ |
if (((head - 1) & (elements.length - 1)) != fence || |
618 |
+ |
(result = elements[cursor]) == null) |
619 |
+ |
throw new ConcurrentModificationException(); |
620 |
+ |
lastRet = cursor; |
621 |
+ |
cursor = (cursor - 1) & (elements.length - 1); |
622 |
+ |
return result; |
623 |
+ |
} |
624 |
+ |
|
625 |
+ |
public void remove() { |
626 |
+ |
if (lastRet >= elements.length) |
627 |
+ |
throw new IllegalStateException(); |
628 |
+ |
if (!delete(lastRet)) |
629 |
+ |
cursor = (cursor + 1) & (elements.length - 1); |
630 |
+ |
lastRet = elements.length; |
631 |
+ |
fence = (head - 1) & (elements.length - 1); |
632 |
+ |
} |
633 |
+ |
} |
634 |
+ |
|
635 |
|
/** |
636 |
|
* Returns <tt>true</tt> if this deque contains the specified element. |
637 |
|
* More formally, returns <tt>true</tt> if and only if this deque contains |
790 |
|
s.defaultWriteObject(); |
791 |
|
|
792 |
|
// Write out size |
793 |
< |
int size = size(); |
748 |
< |
s.writeInt(size); |
793 |
> |
s.writeInt(size()); |
794 |
|
|
795 |
|
// Write out elements in order. |
751 |
– |
int i = head; |
796 |
|
int mask = elements.length - 1; |
797 |
< |
for (int j = 0; j < size; j++) { |
797 |
> |
for (int i = head; i != tail; i = (i + 1) & mask) |
798 |
|
s.writeObject(elements[i]); |
755 |
– |
i = (i + 1) & mask; |
756 |
– |
} |
799 |
|
} |
800 |
|
|
801 |
|
/** |