AImager-Strategy

根据注入的策略类决定执行哪个策略。
php实现

interface IStrategy {
    public function execute();
}

class ConcreteStrategyA implements IStrategy {
    public function execute() {
        echo "Called ConcreteStrategyA execute method\n";
    }
}

class ConcreteStrategyB implements IStrategy {
    public function execute() {
        echo "Called ConcreteStrategyB execute method\n";
    }
}

class ConcreteStrategyC implements IStrategy {
    public function execute() {
        echo "Called ConcreteStrategyC execute method\n";
    }
}

class Context {
    var $strategy;

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

    public function execute() {
        $this->strategy->execute();
    }
}

$context = new Context(new ConcreteStrategyA());
$context->execute();

$context = new Context(new ConcreteStrategyB());
$context->execute();

$context = new Context(new ConcreteStrategyC());
$context->execute();