92 lines
2.6 KiB
PHP
92 lines
2.6 KiB
PHP
<?php
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/**
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* PHP Basics
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*
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* Copyright (C) 2024 Sebastian Meyer <sebastian.meyer@opencultureconsulting.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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declare(strict_types=1);
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namespace OCC\Basics\Traits;
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use LogicException;
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/**
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* Allows just a single instance of the class using this trait.
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*
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* Get the singleton by calling the static method `getInstance()`.
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*
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* If there is no object yet, the constructor is called with the same arguments
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* as `getInstance()`. Any later call will just return the already instantiated
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* object (irrespective of the given arguments).
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*
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* In order for this to work as expected, the constructor has to be implemented
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* as `private` to prevent direct instantiation of the class.
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*
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* @author Sebastian Meyer <sebastian.meyer@opencultureconsulting.com>
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* @package Basics\Traits
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*/
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trait Singleton
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{
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/**
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* Holds the singleton instance.
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*
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* @var array<class-string, static>
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*
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* @internal
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*/
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private static array $_singleton = [];
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/**
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* Get a singleton instance of this class.
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*
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* @param mixed ...$args Constructor arguments
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*
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* @return static The singleton instance
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*
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* @api
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*/
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final public static function getInstance(mixed ...$args): static
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{
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if (!isset(static::$_singleton[static::class])) {
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static::$_singleton[static::class] = new static(...$args);
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}
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return static::$_singleton[static::class];
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}
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/**
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* This is a singleton class, thus the constructor is private.
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*
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* @return void
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*
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* @see Singleton::getInstance() to get an singleton object of the class
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*/
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abstract private function __construct();
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/**
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* This is a singleton class, thus cloning is prohibited.
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*
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* @return void
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*
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* @throws LogicException when trying to clone the singleton object
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*/
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final public function __clone()
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{
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throw new LogicException('Cloning a singleton is prohibited.');
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}
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}
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