Queue.php

<?php


/**
 * This file is part of the ramsey/collection library
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * @copyright Copyright (c) Ben Ramsey <ben@benramsey.com>
 * @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 Ramsey\Collection\Tool\TypeTrait;
use Ramsey\Collection\Tool\ValueToStringTrait;
use function array_key_first;

/**
 * This class provides a basic implementation of `QueueInterface`, to minimize
 * the effort required to implement this interface.
 *
 * @template T
 * @extends AbstractArray<T>
 * @implements QueueInterface<T>
 */
class Queue extends AbstractArray implements QueueInterface {
    use TypeTrait;
    use ValueToStringTrait;
    
    /**
     * Constructs a queue object of the specified type, optionally with the
     * specified data.
     *
     * @param string $queueType The type or class name associated with this queue.
     * @param array<array-key, T> $data The initial items to store in the queue.
     */
    public function __construct(string $queueType, array $data = []) {
        parent::__construct($data);
    }
    
    /**
     * {@inheritDoc}
     *
     * Since arbitrary offsets may not be manipulated in a queue, this method
     * serves only to fulfill the `ArrayAccess` interface requirements. It is
     * invoked by other operations when adding values to the queue.
     *
     * @throws InvalidArgumentException if $value is of the wrong type.
     */
    public function offsetSet(mixed $offset, mixed $value) : void {
        if ($this->checkType($this->getType(), $value) === false) {
            throw new InvalidArgumentException('Value must be of type ' . $this->getType() . '; value is ' . $this->toolValueToString($value));
        }
        $this->data[] = $value;
    }
    
    /**
     * @throws InvalidArgumentException if $value is of the wrong type.
     */
    public function add(mixed $element) : bool {
        $this[] = $element;
        return true;
    }
    
    /**
     * @return T
     *
     * @throws NoSuchElementException if this queue is empty.
     */
    public function element() : mixed {
        return $this->peek() ?? throw new NoSuchElementException('Can\'t return element from Queue. Queue is empty.');
    }
    public function offer(mixed $element) : bool {
        try {
            return $this->add($element);
        } catch (InvalidArgumentException) {
            return false;
        }
    }
    
    /**
     * @return T | null
     */
    public function peek() : mixed {
        $index = array_key_first($this->data);
        if ($index === null) {
            return null;
        }
        return $this[$index];
    }
    
    /**
     * @return T | null
     */
    public function poll() : mixed {
        $index = array_key_first($this->data);
        if ($index === null) {
            return null;
        }
        $head = $this[$index];
        unset($this[$index]);
        return $head;
    }
    
    /**
     * @return T
     *
     * @throws NoSuchElementException if this queue is empty.
     */
    public function remove() : mixed {
        return $this->poll() ?? throw new NoSuchElementException('Can\'t return element from Queue. Queue is empty.');
    }
    public function getType() : string {
        return $this->queueType;
    }

}