#strategypattern

The Strategy pattern allows you to switch the algorithm or strategy based upon the situation. The pattern defines a family of algorithms, encapsulate each one, and make them interchangeable and lets the algorithm vary independently from clients that use it.

Down below, a simple implementation of the Strategy pattern made with PHP:

First, a comparator interface and two concrete implementations.

interface ComparatorInterface { public function compare($a, $b): int; }

class DateComparator implements ComparatorInterface { public function compare($a, $b): int { $aDate = new \DateTime($a['date']); $bDate = new \DateTime($b['date']); return $aDate <=> $bDate; } }

class IdComparator implements ComparatorInterface { public function compare($a, $b): int { return $a['id'] <=> $b['id']; } }

…and an object comparator

class ObjectComparator { private $elements; private $comparator; public function __construct(array $elements = []) { $this->elements = $elements; } public function sort(): array { if (!$this->comparator) { throw new \LogicException('Comparator is not set'); } uasort($this->elements, [$this->comparator, 'compare']); return $this->elements; } public function setComparator(ComparatorInterface $comparator) { $this->comparator = $comparator; } }

…and in use!