170 lines
3.8 KiB
PHP
170 lines
3.8 KiB
PHP
<?php
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/**
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* This file is part of the ramsey/collection library
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*
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* @copyright Copyright (c) Ben Ramsey <ben@benramsey.com>
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* @license http://opensource.org/licenses/MIT MIT
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*/
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declare(strict_types=1);
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namespace Ramsey\Collection;
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use Ramsey\Collection\Exception\InvalidArgumentException;
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use Ramsey\Collection\Exception\NoSuchElementException;
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use Ramsey\Collection\Tool\TypeTrait;
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use Ramsey\Collection\Tool\ValueToStringTrait;
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/**
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* This class provides a basic implementation of `QueueInterface`, to minimize
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* the effort required to implement this interface.
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*
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* @template T
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* @extends AbstractArray<T>
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* @implements QueueInterface<T>
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*/
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class Queue extends AbstractArray implements QueueInterface
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{
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use TypeTrait;
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use ValueToStringTrait;
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/**
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* The type of elements stored in this queue.
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*
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* A queue's type is immutable once it is set. For this reason, this
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* property is set private.
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*/
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private string $queueType;
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/**
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* The index of the head of the queue.
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*/
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protected int $index = 0;
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/**
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* Constructs a queue object of the specified type, optionally with the
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* specified data.
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*
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* @param string $queueType The type (FQCN) associated with this queue.
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* @param array<array-key, T> $data The initial items to store in the collection.
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*/
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public function __construct(string $queueType, array $data = [])
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{
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$this->queueType = $queueType;
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parent::__construct($data);
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}
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/**
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* {@inheritDoc}
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*
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* Since arbitrary offsets may not be manipulated in a queue, this method
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* serves only to fulfill the `ArrayAccess` interface requirements. It is
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* invoked by other operations when adding values to the queue.
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*
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* @throws InvalidArgumentException if $value is of the wrong type
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*/
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public function offsetSet($offset, $value): void
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{
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if ($this->checkType($this->getType(), $value) === false) {
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throw new InvalidArgumentException(
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'Value must be of type ' . $this->getType() . '; value is '
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. $this->toolValueToString($value),
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);
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}
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$this->data[] = $value;
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}
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/**
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* @throws InvalidArgumentException if $value is of the wrong type
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*
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* @inheritDoc
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*/
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public function add($element): bool
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{
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$this[] = $element;
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return true;
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}
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/**
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* @inheritDoc
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*/
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public function element()
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{
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$element = $this->peek();
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if ($element === null) {
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throw new NoSuchElementException(
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'Can\'t return element from Queue. Queue is empty.',
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);
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}
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return $element;
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}
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/**
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* @inheritDoc
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*/
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public function offer($element): bool
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{
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try {
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return $this->add($element);
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} catch (InvalidArgumentException $e) {
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return false;
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}
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}
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/**
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* @inheritDoc
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*/
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public function peek()
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{
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if ($this->count() === 0) {
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return null;
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}
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return $this[$this->index];
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}
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/**
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* @inheritDoc
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*/
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public function poll()
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{
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if ($this->count() === 0) {
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return null;
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}
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$head = $this[$this->index];
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unset($this[$this->index]);
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$this->index++;
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return $head;
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}
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/**
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* @inheritDoc
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*/
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public function remove()
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{
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$head = $this->poll();
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if ($head === null) {
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throw new NoSuchElementException('Can\'t return element from Queue. Queue is empty.');
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}
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return $head;
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}
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public function getType(): string
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{
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return $this->queueType;
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}
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}
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