* @license http://opensource.org/licenses/MIT MIT */ declare(strict_types=1); namespace Ramsey\Collection; use Ramsey\Collection\Exception\InvalidArgumentException; use Ramsey\Collection\Exception\NoSuchElementException; use function array_key_last; use function array_pop; use function array_unshift; /** * This class provides a basic implementation of `DoubleEndedQueueInterface`, to * minimize the effort required to implement this interface. * * @template T * @extends Queue * @implements DoubleEndedQueueInterface */ class DoubleEndedQueue extends Queue implements DoubleEndedQueueInterface { /** * Constructs a double-ended queue (dequeue) object of the specified type, * optionally with the specified data. * * @param string $queueType The type or class name associated with this dequeue. * @param array $data The initial items to store in the dequeue. */ public function __construct(private readonly string $queueType, array $data = []) { parent::__construct($this->queueType, $data); } /** * @throws InvalidArgumentException if $element is of the wrong type */ public function addFirst(mixed $element): bool { if ($this->checkType($this->getType(), $element) === false) { throw new InvalidArgumentException( 'Value must be of type ' . $this->getType() . '; value is ' . $this->toolValueToString($element), ); } array_unshift($this->data, $element); return true; } /** * @throws InvalidArgumentException if $element is of the wrong type */ public function addLast(mixed $element): bool { return $this->add($element); } public function offerFirst(mixed $element): bool { try { return $this->addFirst($element); } catch (InvalidArgumentException) { return false; } } public function offerLast(mixed $element): bool { return $this->offer($element); } /** * @return T the first element in this queue. * * @throws NoSuchElementException if the queue is empty */ public function removeFirst(): mixed { return $this->remove(); } /** * @return T the last element in this queue. * * @throws NoSuchElementException if this queue is empty. */ public function removeLast(): mixed { return $this->pollLast() ?? throw new NoSuchElementException( 'Can\'t return element from Queue. Queue is empty.', ); } /** * @return T | null the head of this queue, or `null` if this queue is empty. */ public function pollFirst(): mixed { return $this->poll(); } /** * @return T | null the tail of this queue, or `null` if this queue is empty. */ public function pollLast(): mixed { return array_pop($this->data); } /** * @return T the head of this queue. * * @throws NoSuchElementException if this queue is empty. */ public function firstElement(): mixed { return $this->element(); } /** * @return T the tail of this queue. * * @throws NoSuchElementException if this queue is empty. */ public function lastElement(): mixed { return $this->peekLast() ?? throw new NoSuchElementException( 'Can\'t return element from Queue. Queue is empty.', ); } /** * @return T | null the head of this queue, or `null` if this queue is empty. */ public function peekFirst(): mixed { return $this->peek(); } /** * @return T | null the tail of this queue, or `null` if this queue is empty. */ public function peekLast(): mixed { $lastIndex = array_key_last($this->data); if ($lastIndex === null) { return null; } return $this->data[$lastIndex]; } }