vendor/league/tactician/src/CommandBus.php line 35

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  1. <?php
  3. namespace League\Tactician;
  5. use League\Tactician\Exception\InvalidCommandException;
  6. use League\Tactician\Exception\InvalidMiddlewareException;
  8. /**
  9. * Receives a command and sends it through a chain of middleware for processing.
  10. *
  11. * @final
  12. */
  13. class CommandBus
  14. {
  15. /**
  16. * @var callable
  17. */
  18. private $middlewareChain;
  20. /**
  21. * @param Middleware[] $middleware
  22. */
  23. public function __construct(array $middleware)
  24. {
  25. $this->middlewareChain = $this->createExecutionChain($middleware);
  26. }
  28. /**
  29. * Executes the given command and optionally returns a value
  30. *
  31. * @param object $command
  32. *
  33. * @return mixed
  34. */
  35. public function handle($command)
  36. {
  37. if (!is_object($command)) {
  38. throw InvalidCommandException::forUnknownValue($command);
  39. }
  41. $middlewareChain = $this->middlewareChain;
  42. return $middlewareChain($command);
  43. }
  45. /**
  46. * @param Middleware[] $middlewareList
  47. *
  48. * @return callable
  49. */
  50. private function createExecutionChain($middlewareList)
  51. {
  52. $lastCallable = function () {
  53. // the final callable is a no-op
  54. };
  56. while ($middleware = array_pop($middlewareList)) {
  57. if (! $middleware instanceof Middleware) {
  58. throw InvalidMiddlewareException::forMiddleware($middleware);
  59. }
  61. $lastCallable = function ($command) use ($middleware, $lastCallable) {
  62. return $middleware->execute($command, $lastCallable);
  63. };
  64. }
  66. return $lastCallable;
  67. }
  68. }