Complex classes like ViewHandler often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use ViewHandler, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 31 | final class ViewHandler implements ConfigurableViewHandlerInterface |
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| 32 | { |
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| 33 | /** |
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| 34 | * Key format, value a callable that returns a Response instance. |
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| 35 | * |
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| 36 | * @var array |
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| 37 | */ |
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| 38 | private $customHandlers = []; |
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| 39 | |||
| 40 | /** |
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| 41 | * The supported formats as keys. |
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| 42 | * |
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| 43 | * @var array |
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| 44 | */ |
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| 45 | private $formats; |
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| 46 | private $failedValidationCode; |
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| 47 | private $emptyContentCode; |
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| 48 | private $serializeNull; |
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| 49 | private $exclusionStrategyGroups = []; |
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| 50 | private $exclusionStrategyVersion; |
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| 51 | private $serializeNullStrategy; |
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| 52 | private $urlGenerator; |
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| 53 | private $serializer; |
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| 54 | private $requestStack; |
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| 55 | private $options; |
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| 56 | |||
| 57 | 54 | private function __construct( |
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| 58 | UrlGeneratorInterface $urlGenerator, |
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| 59 | Serializer $serializer, |
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| 60 | RequestStack $requestStack, |
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| 61 | array $formats = null, |
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| 62 | int $failedValidationCode = Response::HTTP_BAD_REQUEST, |
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| 63 | int $emptyContentCode = Response::HTTP_NO_CONTENT, |
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| 64 | bool $serializeNull = false, |
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| 65 | array $options = [] |
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| 66 | ) { |
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| 67 | 54 | $this->urlGenerator = $urlGenerator; |
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| 68 | 54 | $this->serializer = $serializer; |
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| 69 | 54 | $this->requestStack = $requestStack; |
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| 70 | 54 | $this->formats = (array) $formats; |
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| 71 | 54 | $this->failedValidationCode = $failedValidationCode; |
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| 72 | 54 | $this->emptyContentCode = $emptyContentCode; |
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| 73 | 54 | $this->serializeNull = $serializeNull; |
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| 74 | 54 | $this->options = $options + [ |
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| 75 | 54 | 'exclusionStrategyGroups' => [], |
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| 76 | 'exclusionStrategyVersion' => null, |
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| 77 | 'serializeNullStrategy' => null, |
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| 78 | ]; |
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| 79 | 54 | $this->reset(); |
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| 80 | 54 | } |
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| 81 | |||
| 82 | 54 | public static function create( |
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| 83 | UrlGeneratorInterface $urlGenerator, |
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| 84 | Serializer $serializer, |
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| 85 | RequestStack $requestStack, |
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| 86 | array $formats = null, |
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| 87 | int $failedValidationCode = Response::HTTP_BAD_REQUEST, |
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| 88 | int $emptyContentCode = Response::HTTP_NO_CONTENT, |
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| 89 | bool $serializeNull = false, |
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| 90 | array $options = [] |
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| 91 | ): self |
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| 92 | { |
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| 93 | 54 | return new self($urlGenerator, $serializer, $requestStack, $formats, $failedValidationCode, $emptyContentCode, $serializeNull, $options); |
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| 94 | } |
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| 95 | |||
| 96 | /** |
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| 97 | * @param string[]|string $groups |
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| 98 | */ |
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| 99 | 1 | public function setExclusionStrategyGroups($groups): void |
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| 100 | { |
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| 101 | 1 | $this->exclusionStrategyGroups = (array) $groups; |
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| 102 | 1 | } |
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| 103 | |||
| 104 | 8 | public function setExclusionStrategyVersion(string $version): void |
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| 105 | { |
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| 106 | 8 | $this->exclusionStrategyVersion = $version; |
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| 107 | 8 | } |
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| 108 | |||
| 109 | 3 | public function setSerializeNullStrategy(bool $isEnabled): void |
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| 110 | { |
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| 111 | 3 | $this->serializeNullStrategy = $isEnabled; |
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| 112 | 3 | } |
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| 113 | |||
| 114 | /** |
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| 115 | * {@inheritdoc} |
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| 116 | */ |
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| 117 | 32 | public function supports(string $format): bool |
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| 118 | { |
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| 119 | 32 | return isset($this->customHandlers[$format]) || isset($this->formats[$format]); |
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| 120 | } |
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| 121 | |||
| 122 | /** |
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| 123 | * Registers a custom handler. |
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| 124 | * |
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| 125 | * The handler must have the following signature: handler(ViewHandler $viewHandler, View $view, Request $request, $format) |
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| 126 | * It can use the public methods of this class to retrieve the needed data and return a |
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| 127 | * Response object ready to be sent. |
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| 128 | */ |
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| 129 | 15 | public function registerHandler(string $format, callable $callable): void |
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| 130 | { |
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| 131 | 15 | $this->customHandlers[$format] = $callable; |
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| 132 | 15 | } |
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| 133 | |||
| 134 | /** |
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| 135 | * Handles a request with the proper handler. |
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| 136 | * |
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| 137 | * Decides on which handler to use based on the request format. |
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| 138 | * |
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| 139 | * @throws UnsupportedMediaTypeHttpException |
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| 140 | */ |
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| 141 | 28 | public function handle(View $view, Request $request = null): Response |
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| 142 | { |
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| 143 | 28 | if (null === $request) { |
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| 144 | 2 | $request = $this->requestStack->getCurrentRequest(); |
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| 145 | } |
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| 146 | |||
| 147 | 28 | $format = $view->getFormat() ?: $request->getRequestFormat(); |
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| 148 | |||
| 149 | 28 | if (!$this->supports($format)) { |
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| 150 | 1 | $msg = "Format '$format' not supported, handler must be implemented"; |
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| 151 | |||
| 152 | 1 | throw new UnsupportedMediaTypeHttpException($msg); |
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| 153 | } |
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| 154 | |||
| 155 | 27 | if (isset($this->customHandlers[$format])) { |
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| 156 | 10 | return call_user_func($this->customHandlers[$format], $this, $view, $request, $format); |
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| 157 | } |
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| 158 | |||
| 159 | 17 | return $this->createResponse($view, $request, $format); |
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| 160 | } |
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| 161 | |||
| 162 | 4 | public function createRedirectResponse(View $view, string $location, string $format): Response |
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| 163 | { |
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| 164 | 4 | $content = null; |
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| 165 | 4 | if ((Response::HTTP_CREATED === $view->getStatusCode() || Response::HTTP_ACCEPTED === $view->getStatusCode()) && null !== $view->getData()) { |
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| 166 | 1 | $response = $this->initResponse($view, $format); |
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| 167 | } else { |
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| 168 | 3 | $response = $view->getResponse(); |
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| 169 | } |
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| 170 | |||
| 171 | 4 | $code = $this->getStatusCode($view, $content); |
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| 172 | |||
| 173 | 4 | $response->setStatusCode($code); |
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| 174 | 4 | $response->headers->set('Location', $location); |
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| 175 | |||
| 176 | 4 | return $response; |
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| 177 | } |
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| 178 | |||
| 179 | 33 | public function createResponse(View $view, Request $request, string $format): Response |
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| 180 | { |
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| 181 | 33 | $route = $view->getRoute(); |
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| 182 | |||
| 183 | 33 | $location = $route |
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| 184 | 2 | ? $this->urlGenerator->generate($route, (array) $view->getRouteParameters(), UrlGeneratorInterface::ABSOLUTE_URL) |
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| 185 | 33 | : $view->getLocation(); |
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| 186 | |||
| 187 | 33 | if ($location) { |
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| 188 | 4 | return $this->createRedirectResponse($view, $location, $format); |
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| 189 | } |
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| 190 | |||
| 191 | 29 | $response = $this->initResponse($view, $format); |
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| 192 | |||
| 193 | 29 | if (!$response->headers->has('Content-Type')) { |
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| 194 | 29 | $mimeType = $request->attributes->get('media_type'); |
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| 195 | 29 | if (null === $mimeType) { |
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| 196 | 22 | $mimeType = $request->getMimeType($format); |
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| 197 | } |
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| 198 | |||
| 199 | 29 | $response->headers->set('Content-Type', $mimeType); |
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| 200 | } |
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| 201 | |||
| 202 | 29 | return $response; |
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| 203 | } |
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| 204 | |||
| 205 | /** |
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| 206 | * Gets a response HTTP status code from a View instance. |
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| 207 | * |
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| 208 | * By default it will return 200. However if there is a FormInterface stored for |
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| 209 | * the key 'form' in the View's data it will return the failed_validation |
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| 210 | * configuration if the form instance has errors. |
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| 211 | * |
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| 212 | * @param string|false|null |
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| 213 | */ |
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| 214 | 40 | private function getStatusCode(View $view, $content = null): int |
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| 229 | |||
| 230 | 30 | private function getSerializationContext(View $view): Context |
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| 231 | { |
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| 232 | 30 | $context = $view->getContext(); |
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| 233 | |||
| 234 | 30 | $groups = $context->getGroups(); |
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| 235 | 30 | if (empty($groups) && $this->exclusionStrategyGroups) { |
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| 236 | 1 | $context->setGroups($this->exclusionStrategyGroups); |
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| 237 | } |
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| 238 | |||
| 239 | 30 | if (null === $context->getVersion() && $this->exclusionStrategyVersion) { |
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| 253 | |||
| 254 | 30 | private function initResponse(View $view, string $format): Response |
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| 278 | |||
| 279 | 40 | private function getFormFromView(View $view): ?FormInterface |
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| 293 | |||
| 294 | 27 | private function getDataFromView(View $view) |
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| 304 | |||
| 305 | 54 | public function reset(): void |
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| 311 | } |
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| 312 |
If a variable is not always an object, we recommend to add an additional type check to ensure your method call is safe: