Complex classes like ChainRenderer 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 ChainRenderer, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 20 | class ChainRenderer implements CanSetTemplateRendererInterface |
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| 21 | { |
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| 22 | |||
| 23 | /** |
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| 24 | * @var ChainableRendererInterface|null |
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| 25 | */ |
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| 26 | private $templateRenderer; |
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| 27 | /** |
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| 28 | * @var ChainableRendererInterface[] |
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| 29 | */ |
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| 30 | private $packageRenderers = []; |
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| 31 | /** |
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| 32 | * @var ChainableRendererInterface[] |
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| 33 | */ |
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| 34 | private $customRenderers = []; |
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| 35 | |||
| 36 | private $cacheService; |
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| 37 | |||
| 38 | private $initDone = false; |
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| 39 | /** |
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| 40 | * @var string[] |
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| 41 | */ |
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| 42 | private $customRendererInstanceNames; |
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| 43 | /** |
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| 44 | * @var string |
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| 45 | */ |
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| 46 | private $templateRendererInstanceName; |
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| 47 | /** |
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| 48 | * @var string[] |
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| 49 | */ |
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| 50 | private $packageRendererInstanceNames; |
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| 51 | /** |
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| 52 | * @var string |
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| 53 | */ |
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| 54 | private $uniqueName; |
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| 55 | /** |
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| 56 | * @var ContainerInterface |
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| 57 | */ |
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| 58 | private $container; |
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| 59 | |||
| 60 | /** |
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| 61 | * |
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| 62 | * @param string[] $customRendererInstanceNames An array of names of custom renderers (container identifiers) |
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| 63 | * @param string[] $packageRendererInstanceNames An array of names of package renderers (container identifiers) |
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| 64 | * @param CacheInterface $cacheService This service is used to speed up the mapping between the object and the template. |
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| 65 | * @param string $uniqueName The unique name for this instance (used for caching purpose) |
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| 66 | */ |
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| 67 | public function __construct(ContainerInterface $container, array $customRendererInstanceNames, array $packageRendererInstanceNames, CacheInterface $cacheService, string $uniqueName) |
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| 75 | |||
| 76 | /** |
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| 77 | * (non-PHPdoc) |
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| 78 | * @see \Mouf\Html\Renderer\RendererInterface::render() |
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| 79 | */ |
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| 80 | public function render($object, string $context = null): void |
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| 88 | |||
| 89 | /** |
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| 90 | * @param object $object |
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| 91 | * @param string|null $context |
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| 92 | * @return ChainableRendererInterface|null |
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| 93 | */ |
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| 94 | private function getRenderer($object, string $context = null): ?ChainableRendererInterface |
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| 95 | { |
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| 96 | $cacheKey = "chainRendererByClass_".md5($this->uniqueName."/".$this->templateRendererInstanceName."/".get_class($object)."/".$context); |
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| 97 | |||
| 98 | $cachedInstanceName = $this->cacheService->get($cacheKey); |
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| 99 | if ($cachedInstanceName !== null) { |
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| 100 | return $this->container->get($cachedInstanceName); |
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| 101 | } |
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| 102 | |||
| 103 | $this->initRenderersList(); |
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| 104 | |||
| 105 | $isCachable = true; |
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| 106 | $foundRenderer = null; |
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| 107 | $source = null; |
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| 108 | $foundInstanceName = null; |
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| 109 | |||
| 110 | do { |
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| 111 | foreach ($this->customRenderers as $instanceName => $renderer) { |
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| 112 | $result = $renderer->canRender($object, $context); |
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| 113 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CANNOT_RENDER_OBJECT) { |
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| 114 | $isCachable = false; |
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| 115 | } |
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| 116 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CAN_RENDER_CLASS) { |
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| 117 | $foundRenderer = $renderer; |
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| 118 | $foundInstanceName = $instanceName; |
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| 119 | break 2; |
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| 120 | } |
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| 121 | } |
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| 122 | |||
| 123 | if ($this->templateRendererInstanceName && !$this->templateRenderer) { |
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| 124 | $this->templateRenderer = $this->container->get($this->templateRendererInstanceName); |
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| 125 | } |
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| 126 | if ($this->templateRenderer) { |
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| 127 | $result = $this->templateRenderer->canRender($object, $context); |
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| 128 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CANNOT_RENDER_OBJECT) { |
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| 129 | $isCachable = false; |
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| 130 | } |
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| 131 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CAN_RENDER_CLASS) { |
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| 132 | $foundRenderer = $this->templateRenderer; |
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| 133 | break; |
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| 134 | } |
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| 135 | } |
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| 136 | |||
| 137 | foreach ($this->packageRenderers as $instanceName => $renderer) { |
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| 138 | $result = $renderer->canRender($object, $context); |
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| 139 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CANNOT_RENDER_OBJECT) { |
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| 140 | $isCachable = false; |
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| 141 | } |
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| 142 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CAN_RENDER_CLASS) { |
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| 143 | $foundRenderer = $renderer; |
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| 144 | $foundInstanceName = $instanceName; |
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| 145 | break 2; |
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| 146 | } |
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| 147 | } |
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| 148 | } while (false); |
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| 149 | |||
| 150 | if ($isCachable && $foundRenderer) { |
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| 151 | $this->cacheService->set($cacheKey, $foundInstanceName); |
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| 152 | } |
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| 153 | |||
| 154 | return $foundRenderer; |
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| 155 | } |
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| 156 | |||
| 157 | /** |
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| 158 | * Returns a string explaining the steps done to find the renderer. |
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| 159 | * |
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| 160 | * @param object $object |
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| 161 | * @param string $context |
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| 162 | * @return string |
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| 163 | */ |
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| 164 | private function getRendererDebugMessage($object, string $context = null): string |
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| 165 | { |
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| 166 | $debugMessage = ''; |
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| 167 | |||
| 168 | $this->initRenderersList(); |
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| 169 | |||
| 170 | do { |
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| 171 | foreach ($this->customRenderers as $renderer) { |
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| 172 | /* @var $renderer ChainableRendererInterface */ |
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| 173 | |||
| 174 | $debugMessage .= $renderer->debugCanRender($object, $context); |
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| 175 | $result = $renderer->canRender($object, $context); |
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| 176 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CAN_RENDER_CLASS) { |
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| 177 | break 2; |
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| 178 | } |
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| 179 | } |
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| 180 | |||
| 181 | /* @var $renderer ChainableRendererInterface */ |
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| 182 | if ($this->templateRenderer) { |
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| 183 | $debugMessage .= $this->templateRenderer->debugCanRender($object, $context); |
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| 184 | $result = $this->templateRenderer->canRender($object, $context); |
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| 185 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CAN_RENDER_CLASS) { |
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| 186 | break; |
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| 187 | } |
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| 188 | } |
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| 189 | |||
| 190 | foreach ($this->packageRenderers as $renderer) { |
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| 191 | /* @var $renderer ChainableRendererInterface */ |
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| 192 | |||
| 193 | $debugMessage .= $renderer->debugCanRender($object, $context); |
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| 194 | $result = $renderer->canRender($object, $context); |
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| 195 | if ($result === ChainableRendererInterface::CAN_RENDER_OBJECT || $result === ChainableRendererInterface::CAN_RENDER_CLASS) { |
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| 196 | break 2; |
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| 197 | } |
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| 198 | } |
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| 199 | } while (false); |
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| 200 | |||
| 201 | return $debugMessage; |
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| 202 | } |
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| 203 | |||
| 204 | /** |
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| 205 | * Initializes the renderers list (from cache if available) |
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| 206 | */ |
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| 207 | private function initRenderersList(): void |
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| 208 | { |
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| 209 | if (!$this->initDone) { |
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| 210 | foreach ($this->customRendererInstanceNames as $instanceName) { |
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| 211 | $this->customRenderers[$instanceName] = $this->container->get($instanceName); |
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| 212 | } |
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| 213 | foreach ($this->packageRendererInstanceNames as $instanceName) { |
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| 214 | $this->packageRenderers[$instanceName] = $this->container->get($instanceName); |
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| 215 | } |
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| 216 | |||
| 217 | // Note: We ignore template renderers on purpose. |
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| 218 | $this->initDone = true; |
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| 219 | } |
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| 220 | } |
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| 221 | |||
| 222 | /** |
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| 223 | * Sets the renderer associated to the template. |
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| 224 | * There should be only one if these renderers. |
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| 225 | * It is the role of the template to subscribe to this renderer. |
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| 226 | * |
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| 227 | * @param string $templateRendererInstanceName The name of the template renderer in the container |
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| 228 | */ |
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| 229 | public function setTemplateRendererInstanceName(string $templateRendererInstanceName): void |
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| 233 | } |
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| 234 |
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVarassignment in line 1 and the$higherassignment in line 2 are dead. The first because$myVaris never used and the second because$higheris always overwritten for every possible time line.