| 1 | <?php |
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| 16 | class ServiceLocator |
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| 17 | { |
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| 18 | /** |
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| 19 | * method to register a service |
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| 20 | * |
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| 21 | * @param string $serviceKey the key for the service |
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| 22 | * @param mixed $object |
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| 23 | * |
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| 24 | * @throws ServiceLocatorException |
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| 25 | */ |
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| 26 | 27 | public static function registerService($serviceKey, $object) |
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| 30 | |||
| 31 | /** |
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| 32 | * checks if a service is registered |
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| 33 | * |
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| 34 | * @param string $serviceKey |
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| 35 | * |
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| 36 | * @return bool |
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| 37 | */ |
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| 38 | 31 | public static function hasService($serviceKey) |
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| 42 | |||
| 43 | /** |
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| 44 | * returns a service |
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| 45 | * |
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| 46 | * @param string $serviceKey the service key |
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| 47 | * |
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| 48 | * @return mixed |
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| 49 | * @throws ServiceLocatorException |
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| 50 | */ |
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| 51 | 29 | public static function getService($serviceKey) |
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| 55 | } |
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| 56 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: