Complex classes like ViewHelperResolver 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 ViewHelperResolver, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 23 | class ViewHelperResolver |
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| 24 | { |
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| 25 | |||
| 26 | /** |
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| 27 | * @var array |
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| 28 | */ |
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| 29 | protected $resolvedViewHelperClassNames = []; |
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| 30 | |||
| 31 | /** |
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| 32 | * Namespaces requested by the template being rendered, |
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| 33 | * in [shortname => phpnamespace] format. |
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| 34 | * |
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| 35 | * @var array |
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| 36 | */ |
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| 37 | protected $namespaces = [ |
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| 38 | 'f' => ['TYPO3Fluid\\Fluid\\ViewHelpers'] |
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| 39 | ]; |
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| 40 | |||
| 41 | /** |
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| 42 | * @return array |
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| 43 | */ |
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| 44 | public function getNamespaces() |
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| 48 | |||
| 49 | /** |
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| 50 | * Add a PHP namespace where ViewHelpers can be found and give |
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| 51 | * it an alias/identifier. |
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| 52 | * |
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| 53 | * The provided namespace can be either a single namespace or |
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| 54 | * an array of namespaces, as strings. The identifier/alias is |
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| 55 | * always a single, alpha-numeric ASCII string. |
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| 56 | * |
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| 57 | * Calling this method multiple times with different PHP namespaces |
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| 58 | * for the same alias causes that namespace to be *extended*, |
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| 59 | * meaning that the PHP namespace you provide second, third etc. |
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| 60 | * are also used in lookups and are used *first*, so that if any |
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| 61 | * of the namespaces you add contains a class placed and named the |
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| 62 | * same way as one that exists in an earlier namespace, then your |
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| 63 | * class gets used instead of the earlier one. |
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| 64 | * |
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| 65 | * Example: |
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| 66 | * |
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| 67 | * $resolver->addNamespace('my', 'My\Package\ViewHelpers'); |
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| 68 | * // Any ViewHelpers under this namespace can now be accessed using for example {my:example()} |
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| 69 | * // Now, assuming you also have an ExampleViewHelper class in a different |
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| 70 | * // namespace and wish to make that ExampleViewHelper override the other: |
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| 71 | * $resolver->addNamespace('my', 'My\OtherPackage\ViewHelpers'); |
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| 72 | * // Now, since ExampleViewHelper exists in both places but the |
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| 73 | * // My\OtherPackage\ViewHelpers namespace was added *last*, Fluid |
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| 74 | * // will find and use My\OtherPackage\ViewHelpers\ExampleViewHelper. |
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| 75 | * |
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| 76 | * Alternatively, setNamespaces() can be used to reset and redefine |
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| 77 | * all previously added namespaces - which is great for cases where |
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| 78 | * you need to remove or replace previously added namespaces. Be aware |
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| 79 | * that setNamespaces() also removes the default "f" namespace, so |
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| 80 | * when you use this method you should always include the "f" namespace. |
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| 81 | * |
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| 82 | * @param string $identifier |
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| 83 | * @param string|array $phpNamespace |
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| 84 | * @return void |
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| 85 | */ |
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| 86 | public function addNamespace($identifier, $phpNamespace) |
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| 87 | { |
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| 88 | if (!array_key_exists($identifier, $this->namespaces) || $this->namespaces[$identifier] === null) { |
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| 89 | $this->namespaces[$identifier] = $phpNamespace === null ? null : (array) $phpNamespace; |
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| 90 | } elseif (is_array($phpNamespace)) { |
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| 91 | $this->namespaces[$identifier] = array_unique(array_merge($this->namespaces[$identifier], $phpNamespace)); |
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| 92 | } elseif (isset($this->namespaces[$identifier]) && !in_array($phpNamespace, $this->namespaces[$identifier])) { |
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| 93 | $this->namespaces[$identifier][] = $phpNamespace; |
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| 94 | } |
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| 95 | } |
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| 96 | |||
| 97 | /** |
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| 98 | * Wrapper to allow adding namespaces in bulk *without* first |
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| 99 | * clearing the already added namespaces. Utility method mainly |
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| 100 | * used in compiled templates, where some namespaces can be added |
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| 101 | * from outside and some can be added from compiled values. |
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| 102 | * |
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| 103 | * @param array $namespaces |
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| 104 | * @return void |
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| 105 | */ |
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| 106 | public function addNamespaces(array $namespaces) |
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| 112 | |||
| 113 | /** |
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| 114 | * Resolves the PHP namespace based on the Fluid xmlns namespace, |
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| 115 | * which can be either a URL matching the Patterns::NAMESPACEPREFIX |
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| 116 | * and Patterns::NAMESPACESUFFIX rules, or a PHP namespace. When |
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| 117 | * namespace is a PHP namespace it is optional to suffix it with |
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| 118 | * the "\ViewHelpers" segment, e.g. "My\Package" is as valid to |
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| 119 | * use as "My\Package\ViewHelpers" is. |
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| 120 | * |
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| 121 | * @param string $fluidNamespace |
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| 122 | * @return string |
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| 123 | */ |
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| 124 | public function resolvePhpNamespaceFromFluidNamespace($fluidNamespace) |
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| 140 | |||
| 141 | /** |
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| 142 | * Set all namespaces as an array of ['identifier' => ['Php\Namespace1', 'Php\Namespace2']] |
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| 143 | * namespace definitions. For convenience and legacy support, a |
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| 144 | * format of ['identifier' => 'Only\Php\Namespace'] is allowed, |
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| 145 | * but will internally convert the namespace to an array and |
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| 146 | * allow it to be extended by addNamespace(). |
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| 147 | * |
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| 148 | * Note that when using this method the default "f" namespace is |
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| 149 | * also removed and so must be included in $namespaces or added |
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| 150 | * after using addNamespace(). Or, add the PHP namespaces that |
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| 151 | * belonged to "f" as a new alias and use that in your templates. |
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| 152 | * |
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| 153 | * Use getNamespaces() to get an array of currently added namespaces. |
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| 154 | * |
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| 155 | * @param array $namespaces |
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| 156 | * @return void |
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| 157 | */ |
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| 158 | public function setNamespaces(array $namespaces) |
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| 165 | |||
| 166 | /** |
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| 167 | * Validates the given namespaceIdentifier and returns FALSE |
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| 168 | * if the namespace is unknown, causing the tag to be rendered |
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| 169 | * without processing. |
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| 170 | * |
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| 171 | * @param string $namespaceIdentifier |
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| 172 | * @return boolean TRUE if the given namespace is valid, otherwise FALSE |
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| 173 | */ |
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| 174 | public function isNamespaceValid($namespaceIdentifier) |
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| 186 | |||
| 187 | /** |
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| 188 | * Validates the given namespaceIdentifier and returns FALSE |
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| 189 | * if the namespace is unknown and not ignored |
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| 190 | * |
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| 191 | * @param string $namespaceIdentifier |
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| 192 | * @return boolean TRUE if the given namespace is valid, otherwise FALSE |
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| 193 | */ |
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| 194 | public function isNamespaceValidOrIgnored($namespaceIdentifier) |
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| 210 | |||
| 211 | /** |
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| 212 | * @param string $namespaceIdentifier |
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| 213 | * @return boolean |
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| 214 | */ |
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| 215 | public function isNamespaceIgnored($namespaceIdentifier) |
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| 231 | |||
| 232 | /** |
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| 233 | * Resolves a ViewHelper class name by namespace alias and |
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| 234 | * Fluid-format identity, e.g. "f" and "format.htmlspecialchars". |
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| 235 | * |
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| 236 | * Looks in all PHP namespaces which have been added for the |
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| 237 | * provided alias, starting in the last added PHP namespace. If |
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| 238 | * a ViewHelper class exists in multiple PHP namespaces Fluid |
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| 239 | * will detect and use whichever one was added last. |
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| 240 | * |
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| 241 | * If no ViewHelper class can be detected in any of the added |
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| 242 | * PHP namespaces a Fluid Parser Exception is thrown. |
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| 243 | * |
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| 244 | * @param string $namespaceIdentifier |
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| 245 | * @param string $methodIdentifier |
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| 246 | * @return string|NULL |
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| 247 | * @throws ParserException |
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| 248 | */ |
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| 249 | public function resolveViewHelperClassName($namespaceIdentifier, $methodIdentifier) |
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| 257 | |||
| 258 | /** |
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| 259 | * Can be overridden by custom implementations to change the way |
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| 260 | * classes are loaded when the class is a ViewHelper - for |
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| 261 | * example making it possible to use a DI-aware class loader. |
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| 262 | * |
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| 263 | * @param string $namespace |
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| 264 | * @param string $viewHelperShortName |
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| 265 | * @return ViewHelperInterface |
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| 266 | */ |
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| 267 | public function createViewHelperInstance($namespace, $viewHelperShortName) |
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| 272 | |||
| 273 | /** |
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| 274 | * Wrapper to create a ViewHelper instance by class name. This is |
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| 275 | * the final method called when creating ViewHelper classes - |
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| 276 | * overriding this method allows custom constructors, dependency |
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| 277 | * injections etc. to be performed on the ViewHelper instance. |
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| 278 | * |
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| 279 | * @param string $viewHelperClassName |
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| 280 | * @return ViewHelperInterface |
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| 281 | */ |
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| 282 | public function createViewHelperInstanceFromClassName($viewHelperClassName) |
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| 286 | |||
| 287 | /** |
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| 288 | * Return an array of ArgumentDefinition instances which describe |
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| 289 | * the arguments that the ViewHelper supports. By default, the |
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| 290 | * arguments are simply fetched from the ViewHelper - but custom |
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| 291 | * implementations can if necessary add/remove/replace arguments |
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| 292 | * which will be passed to the ViewHelper. |
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| 293 | * |
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| 294 | * @param ViewHelperInterface $viewHelper |
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| 295 | * @return ArgumentDefinition[] |
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| 296 | */ |
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| 297 | public function getArgumentDefinitionsForViewHelper(ViewHelperInterface $viewHelper) |
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| 301 | |||
| 302 | /** |
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| 303 | * Resolve a viewhelper name. |
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| 304 | * |
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| 305 | * @param string $namespaceIdentifier Namespace identifier for the view helper. |
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| 306 | * @param string $methodIdentifier Method identifier, might be hierarchical like "link.url" |
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| 307 | * @return string The fully qualified class name of the viewhelper |
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| 308 | */ |
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| 309 | protected function resolveViewHelperName($namespaceIdentifier, $methodIdentifier) |
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| 356 | } |
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| 357 |
This check marks access to variables or properties that have not been declared yet. While PHP has no explicit notion of declaring a variable, accessing it before a value is assigned to it is most likely a bug.