PHP設計模式之策略模式(Strategy)程式碼例項大全(30)
阿新 • • 發佈:2020-09-21
目的
分離「策略」並使他們之間能互相快速切換。此外,這種模式是一種不錯的繼承替代方案(替代使用擴充套件抽象類的方式)。
例子
-
簡化版的的單元測試:例如,在使用檔案儲存和記憶體儲存之間互相切換
-
對一個物件列表進行排序,一種按照日期,一種按照 id
UML圖
程式碼
- Context.php
<?php namespace DesignPatterns\Behavioral\Strategy; class Context { /** * @var ComparatorInterface */ private $comparator; public function __construct(ComparatorInterface $comparator) { $this->comparator = $comparator; } public function executeStrategy(array $elements) : array { uasort($elements, [$this->comparator, 'compare']); return $elements; } }
- ComparatorInterface.php
<?php
namespace DesignPatterns\Behavioral\Strategy;
interface ComparatorInterface
{
/**
* @param mixed $a
* @param mixed $b
*
* @return int
*/
public function compare($a, $b): int;
}
- DateComparator.php
<?php namespace DesignPatterns\Behavioral\Strategy; class DateComparator implements ComparatorInterface { /** * @param mixed $a * @param mixed $b * * @return int */ public function compare($a, $b): int { $aDate = new \DateTime($a['date']); $bDate = new \DateTime($b['date']); return $aDate <=> $bDate; } }
- IdComparator.php
<?php
namespace DesignPatterns\Behavioral\Strategy;
class IdComparator implements ComparatorInterface
{
/**
* @param mixed $a
* @param mixed $b
*
* @return int
*/
public function compare($a, $b): int
{
return $a['id'] <=> $b['id'];
}
}
測試
- Tests/StrategyTest.php
<?php
namespace DesignPatterns\Behavioral\Strategy\Tests;
use DesignPatterns\Behavioral\Strategy\Context;
use DesignPatterns\Behavioral\Strategy\DateComparator;
use DesignPatterns\Behavioral\Strategy\IdComparator;
use PHPUnit\Framework\TestCase;
class StrategyTest extends TestCase
{
public function provideIntegers()
{
return [
[
[['id' => 2], ['id' => 1], ['id' => 3]],
['id' => 1],
],
[
[['id' => 3], ['id' => 2], ['id' => 1]],
['id' => 1],
],
];
}
public function provideDates()
{
return [
[
[['date' => '2014-03-03'], ['date' => '2015-03-02'], ['date' => '2013-03-01']],
['date' => '2013-03-01'],
],
[
[['date' => '2014-02-03'], ['date' => '2013-02-01'], ['date' => '2015-02-02']],
['date' => '2013-02-01'],
],
];
}
/**
* @dataProvider provideIntegers
*
* @param array $collection
* @param array $expected
*/
public function testIdComparator($collection, $expected)
{
$obj = new Context(new IdComparator());
$elements = $obj->executeStrategy($collection);
$firstElement = array_shift($elements);
$this->assertEquals($expected, $firstElement);
}
/**
* @dataProvider provideDates
*
* @param array $collection
* @param array $expected
*/
public function testDateComparator($collection, $expected)
{
$obj = new Context(new DateComparator());
$elements = $obj->executeStrategy($collection);
$firstElement = array_shift($elements);
$this->assertEquals($expected, $firstElement);
}
}
PHP 網際網路架構師 50K 成長指南+行業問題解決總綱(持續更新)
面試10家公司,收穫9個offer,2020年PHP 面試問題
★如果喜歡我的文章,想與更多資深開發者一起交流學習的話,獲取更多大廠面試相關技術諮詢和指導,歡迎加入我們的群啊,暗號:phpzh(君羊號碼856460874)。
內容不錯的話希望大家支援鼓勵下點個贊/喜歡,歡迎一起來交流;另外如果有什麼問題 建議 想看的內容可以在評論提出