简介
一组实现了同一个策略接口的策略，能够随时指定用哪一种策略实现业务。
策略模式其实跟桥接模式很像，都是通过持有另一个对象，达到组合的成果。
角色
Context 上下文
可设置应用的 Strategy
- 形象 Strategy
- 具体 Strategy
类图
如图，Context应用setStrategy办法设置以后应用的策略，在doSomething中，调用策略的execute办法，实现动静应用策略。
代码
class Context{ private $strategy; public function __construct(Strategy $strategy) { $this->strategy = $strategy; } public function setStrategy(Strategy $strategy) { $this->strategy = $strategy; } public function doSomeBusinessLogic(): void { echo "Context: Sorting data using the strategy (not sure how it'll do it)\n"; $result = $this->strategy->doAlgorithm(["a", "b", "c", "d", "e"]); echo implode(",", $result) . "\n"; }}interface Strategy{ public function doAlgorithm(array $data): array;}class ConcreteStrategyA implements Strategy{ public function doAlgorithm(array $data): array { sort($data); return $data; }}class ConcreteStrategyB implements Strategy{ public function doAlgorithm(array $data): array { rsort($data); return $data; }}$context = new Context(new ConcreteStrategyA());echo "Client: Strategy is set to normal sorting.\n";$context->doSomeBusinessLogic();echo "Client: Strategy is set to reverse sorting.\n";$context->setStrategy(new ConcreteStrategyB());$context->doSomeBusinessLogic();output:
Client: Strategy is set to normal sorting.Context: Sorting data using the strategy (not sure how it'll do it)a,b,c,d,eClient: Strategy is set to reverse sorting.Context: Sorting data using the strategy (not sure how it'll do it)e,d,c,b,a本文由mdnice多平台公布