327 /**
328 * Retrieves, but does not remove, the first element of this deque,
329 * or returns {@code null} if this deque is empty.
330 *
331 * @return the head of this deque, or {@code null} if this deque is empty
332 */
333 E peekFirst();
334
335 /**
336 * Retrieves, but does not remove, the last element of this deque,
337 * or returns {@code null} if this deque is empty.
338 *
339 * @return the tail of this deque, or {@code null} if this deque is empty
340 */
341 E peekLast();
342
343 /**
344 * Removes the first occurrence of the specified element from this deque.
345 * If the deque does not contain the element, it is unchanged.
346 * More formally, removes the first element {@code e} such that
347 * <tt>(o==null ? e==null : o.equals(e))</tt>
348 * (if such an element exists).
349 * Returns {@code true} if this deque contained the specified element
350 * (or equivalently, if this deque changed as a result of the call).
351 *
352 * @param o element to be removed from this deque, if present
353 * @return {@code true} if an element was removed as a result of this call
354 * @throws ClassCastException if the class of the specified element
355 * is incompatible with this deque
356 * (<a href="Collection.html#optional-restrictions">optional</a>)
357 * @throws NullPointerException if the specified element is null and this
358 * deque does not permit null elements
359 * (<a href="Collection.html#optional-restrictions">optional</a>)
360 */
361 boolean removeFirstOccurrence(Object o);
362
363 /**
364 * Removes the last occurrence of the specified element from this deque.
365 * If the deque does not contain the element, it is unchanged.
366 * More formally, removes the last element {@code e} such that
367 * <tt>(o==null ? e==null : o.equals(e))</tt>
368 * (if such an element exists).
369 * Returns {@code true} if this deque contained the specified element
370 * (or equivalently, if this deque changed as a result of the call).
371 *
372 * @param o element to be removed from this deque, if present
373 * @return {@code true} if an element was removed as a result of this call
374 * @throws ClassCastException if the class of the specified element
375 * is incompatible with this deque
376 * (<a href="Collection.html#optional-restrictions">optional</a>)
377 * @throws NullPointerException if the specified element is null and this
378 * deque does not permit null elements
379 * (<a href="Collection.html#optional-restrictions">optional</a>)
380 */
381 boolean removeLastOccurrence(Object o);
382
383 // *** Queue methods ***
384
385 /**
386 * Inserts the specified element into the queue represented by this deque
387 * (in other words, at the tail of this deque) if it is possible to do so
504
505 /**
506 * Pops an element from the stack represented by this deque. In other
507 * words, removes and returns the first element of this deque.
508 *
509 * <p>This method is equivalent to {@link #removeFirst()}.
510 *
511 * @return the element at the front of this deque (which is the top
512 * of the stack represented by this deque)
513 * @throws NoSuchElementException if this deque is empty
514 */
515 E pop();
516
517
518 // *** Collection methods ***
519
520 /**
521 * Removes the first occurrence of the specified element from this deque.
522 * If the deque does not contain the element, it is unchanged.
523 * More formally, removes the first element {@code e} such that
524 * <tt>(o==null ? e==null : o.equals(e))</tt>
525 * (if such an element exists).
526 * Returns {@code true} if this deque contained the specified element
527 * (or equivalently, if this deque changed as a result of the call).
528 *
529 * <p>This method is equivalent to {@link #removeFirstOccurrence(Object)}.
530 *
531 * @param o element to be removed from this deque, if present
532 * @return {@code true} if an element was removed as a result of this call
533 * @throws ClassCastException if the class of the specified element
534 * is incompatible with this deque
535 * (<a href="Collection.html#optional-restrictions">optional</a>)
536 * @throws NullPointerException if the specified element is null and this
537 * deque does not permit null elements
538 * (<a href="Collection.html#optional-restrictions">optional</a>)
539 */
540 boolean remove(Object o);
541
542 /**
543 * Returns {@code true} if this deque contains the specified element.
544 * More formally, returns {@code true} if and only if this deque contains
545 * at least one element {@code e} such that
546 * <tt>(o==null ? e==null : o.equals(e))</tt>.
547 *
548 * @param o element whose presence in this deque is to be tested
549 * @return {@code true} if this deque contains the specified element
550 * @throws ClassCastException if the type of the specified element
551 * is incompatible with this deque
552 * (<a href="Collection.html#optional-restrictions">optional</a>)
553 * @throws NullPointerException if the specified element is null and this
554 * deque does not permit null elements
555 * (<a href="Collection.html#optional-restrictions">optional</a>)
556 */
557 boolean contains(Object o);
558
559 /**
560 * Returns the number of elements in this deque.
561 *
562 * @return the number of elements in this deque
563 */
564 public int size();
565
566 /**
|
327 /**
328 * Retrieves, but does not remove, the first element of this deque,
329 * or returns {@code null} if this deque is empty.
330 *
331 * @return the head of this deque, or {@code null} if this deque is empty
332 */
333 E peekFirst();
334
335 /**
336 * Retrieves, but does not remove, the last element of this deque,
337 * or returns {@code null} if this deque is empty.
338 *
339 * @return the tail of this deque, or {@code null} if this deque is empty
340 */
341 E peekLast();
342
343 /**
344 * Removes the first occurrence of the specified element from this deque.
345 * If the deque does not contain the element, it is unchanged.
346 * More formally, removes the first element {@code e} such that
347 * <code>(o==null ? e==null : o.equals(e))</code>
348 * (if such an element exists).
349 * Returns {@code true} if this deque contained the specified element
350 * (or equivalently, if this deque changed as a result of the call).
351 *
352 * @param o element to be removed from this deque, if present
353 * @return {@code true} if an element was removed as a result of this call
354 * @throws ClassCastException if the class of the specified element
355 * is incompatible with this deque
356 * (<a href="Collection.html#optional-restrictions">optional</a>)
357 * @throws NullPointerException if the specified element is null and this
358 * deque does not permit null elements
359 * (<a href="Collection.html#optional-restrictions">optional</a>)
360 */
361 boolean removeFirstOccurrence(Object o);
362
363 /**
364 * Removes the last occurrence of the specified element from this deque.
365 * If the deque does not contain the element, it is unchanged.
366 * More formally, removes the last element {@code e} such that
367 * <code>(o==null ? e==null : o.equals(e))</code>
368 * (if such an element exists).
369 * Returns {@code true} if this deque contained the specified element
370 * (or equivalently, if this deque changed as a result of the call).
371 *
372 * @param o element to be removed from this deque, if present
373 * @return {@code true} if an element was removed as a result of this call
374 * @throws ClassCastException if the class of the specified element
375 * is incompatible with this deque
376 * (<a href="Collection.html#optional-restrictions">optional</a>)
377 * @throws NullPointerException if the specified element is null and this
378 * deque does not permit null elements
379 * (<a href="Collection.html#optional-restrictions">optional</a>)
380 */
381 boolean removeLastOccurrence(Object o);
382
383 // *** Queue methods ***
384
385 /**
386 * Inserts the specified element into the queue represented by this deque
387 * (in other words, at the tail of this deque) if it is possible to do so
504
505 /**
506 * Pops an element from the stack represented by this deque. In other
507 * words, removes and returns the first element of this deque.
508 *
509 * <p>This method is equivalent to {@link #removeFirst()}.
510 *
511 * @return the element at the front of this deque (which is the top
512 * of the stack represented by this deque)
513 * @throws NoSuchElementException if this deque is empty
514 */
515 E pop();
516
517
518 // *** Collection methods ***
519
520 /**
521 * Removes the first occurrence of the specified element from this deque.
522 * If the deque does not contain the element, it is unchanged.
523 * More formally, removes the first element {@code e} such that
524 * <code>(o==null ? e==null : o.equals(e))</code>
525 * (if such an element exists).
526 * Returns {@code true} if this deque contained the specified element
527 * (or equivalently, if this deque changed as a result of the call).
528 *
529 * <p>This method is equivalent to {@link #removeFirstOccurrence(Object)}.
530 *
531 * @param o element to be removed from this deque, if present
532 * @return {@code true} if an element was removed as a result of this call
533 * @throws ClassCastException if the class of the specified element
534 * is incompatible with this deque
535 * (<a href="Collection.html#optional-restrictions">optional</a>)
536 * @throws NullPointerException if the specified element is null and this
537 * deque does not permit null elements
538 * (<a href="Collection.html#optional-restrictions">optional</a>)
539 */
540 boolean remove(Object o);
541
542 /**
543 * Returns {@code true} if this deque contains the specified element.
544 * More formally, returns {@code true} if and only if this deque contains
545 * at least one element {@code e} such that
546 * <code>(o==null ? e==null : o.equals(e))</code>.
547 *
548 * @param o element whose presence in this deque is to be tested
549 * @return {@code true} if this deque contains the specified element
550 * @throws ClassCastException if the type of the specified element
551 * is incompatible with this deque
552 * (<a href="Collection.html#optional-restrictions">optional</a>)
553 * @throws NullPointerException if the specified element is null and this
554 * deque does not permit null elements
555 * (<a href="Collection.html#optional-restrictions">optional</a>)
556 */
557 boolean contains(Object o);
558
559 /**
560 * Returns the number of elements in this deque.
561 *
562 * @return the number of elements in this deque
563 */
564 public int size();
565
566 /**
|