What is the Strategy pattern

The Strategy pattern is a behavioral design pattern that enables selecting an algorithm's behavior at runtime. It defines a family of algorithms, encapsulates each one, and makes them interchangeable. This allows a client to choose an algorithm from a family of algorithms without altering the code that uses the algorithm.

This pattern is useful when you have multiple algorithms for a specific task, and you want to switch between them dynamically, promoting the Open/Closed Principle by preventing modifications to the code when introducing new algorithms.

Here’s a simple example of the Strategy pattern implemented in PHP:


        <?php
        // Strategy interface
        interface Strategy {
            public function execute(int $a, int $b): int;
        }

        // Concrete Strategy A
        class Addition implements Strategy {
            public function execute(int $a, int $b): int {
                return $a + $b;
            }
        }

        // Concrete Strategy B
        class Subtraction implements Strategy {
            public function execute(int $a, int $b): int {
                return $a - $b;
            }
        }

        // Context
        class Calculator {
            private $strategy;

            public function __construct(Strategy $strategy) {
                $this->strategy = $strategy;
            }

            public function setStrategy(Strategy $strategy) {
                $this->strategy = $strategy;
            }

            public function calculate(int $a, int $b): int {
                return $this->strategy->execute($a, $b);
            }
        }

        // Client code
        $calculator = new Calculator(new Addition());
        echo $calculator->calculate(5, 3); // Output: 8

        $calculator->setStrategy(new Subtraction());
        echo $calculator->calculate(5, 3); // Output: 2
        ?>

What is the Strategy pattern

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What is the Strategy pattern

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