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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| 27 | class ViewHelperResolver |
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| 28 | { |
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| 29 | /** |
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| 30 | * @var RenderingContextInterface |
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| 31 | */ |
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| 32 | protected $renderingContext; |
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| 33 | |||
| 34 | /** |
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| 35 | * @var array |
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| 36 | */ |
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| 37 | protected $resolvedViewHelperClassNames = []; |
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| 38 | |||
| 39 | /** |
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| 40 | * Atom paths indexed by namespace, in |
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| 41 | * [shortname => [path1, path2, ...]] format. |
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| 42 | * @var array |
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| 43 | */ |
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| 44 | protected $atoms = []; |
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| 45 | |||
| 46 | /** |
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| 47 | * Namespaces requested by the template being rendered, |
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| 48 | * in [shortname => [phpnamespace1, phpnamespace2, ...]] format. |
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| 49 | * |
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| 50 | * @var array |
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| 51 | */ |
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| 52 | protected $namespaces = [ |
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| 53 | 'f' => ['TYPO3Fluid\\Fluid\\ViewHelpers'] |
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| 54 | ]; |
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| 55 | |||
| 56 | /** |
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| 57 | * @var array |
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| 58 | */ |
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| 59 | protected $aliases = [ |
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| 60 | 'html' => ['f', 'html'], |
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| 61 | 'raw' => ['f', 'format.raw'], |
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| 62 | ]; |
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| 63 | |||
| 64 | public function __construct(RenderingContextInterface $renderingContext) |
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| 68 | |||
| 69 | public function addAtomPath(string $namespace, string $path): void |
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| 75 | |||
| 76 | /** |
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| 77 | * Add all Atom paths as array-in-array, with the first level key |
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| 78 | * being the namespace and the value being an array of paths. |
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| 79 | * |
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| 80 | * Example: |
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| 81 | * |
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| 82 | * $resolver->addAtomPaths( |
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| 83 | * [ |
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| 84 | * 'my' => [ |
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| 85 | * 'path/first/', |
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| 86 | * 'path/second/', |
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| 87 | * ], |
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| 88 | * 'other' => [ |
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| 89 | * 'path/third/', |
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| 90 | * ], |
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| 91 | * ] |
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| 92 | * ); |
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| 93 | * |
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| 94 | * @param iterable|string[][] $paths |
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| 95 | */ |
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| 96 | public function addAtomPaths(iterable $paths): void |
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| 104 | |||
| 105 | public function resolveAtom(string $namespace, string $name): ComponentInterface |
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| 117 | |||
| 118 | public function resolveAtomFile(string $namespace, string $name): ?string |
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| 140 | |||
| 141 | /** |
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| 142 | * @return array|string[][] |
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| 143 | */ |
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| 144 | public function getAtoms(): array |
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| 148 | |||
| 149 | /** |
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| 150 | * @return array |
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| 151 | */ |
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| 152 | public function getNamespaces(): array |
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| 156 | |||
| 157 | /** |
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| 158 | * Adds an alias of a ViewHelper, allowing you to call for example |
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| 159 | * |
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| 160 | * @param string $alias |
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| 161 | * @param string $namespace |
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| 162 | * @param string $identifier |
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| 163 | */ |
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| 164 | public function addViewHelperAlias(string $alias, string $namespace, string $identifier) |
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| 168 | |||
| 169 | public function isAliasRegistered(string $alias): bool |
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| 173 | |||
| 174 | /** |
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| 175 | * Add a PHP namespace where ViewHelpers can be found and give |
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| 176 | * it an alias/identifier. |
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| 177 | * |
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| 178 | * The provided namespace can be either a single namespace or |
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| 179 | * an array of namespaces, as strings. The identifier/alias is |
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| 180 | * always a single, alpha-numeric ASCII string. |
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| 181 | * |
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| 182 | * Calling this method multiple times with different PHP namespaces |
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| 183 | * for the same alias causes that namespace to be *extended*, |
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| 184 | * meaning that the PHP namespace you provide second, third etc. |
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| 185 | * are also used in lookups and are used *first*, so that if any |
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| 186 | * of the namespaces you add contains a class placed and named the |
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| 187 | * same way as one that exists in an earlier namespace, then your |
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| 188 | * class gets used instead of the earlier one. |
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| 189 | * |
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| 190 | * Example: |
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| 191 | * |
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| 192 | * $resolver->addNamespace('my', 'My\Package\ViewHelpers'); |
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| 193 | * // Any ViewHelpers under this namespace can now be accessed using for example {my:example()} |
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| 194 | * // Now, assuming you also have an ExampleViewHelper class in a different |
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| 195 | * // namespace and wish to make that ExampleViewHelper override the other: |
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| 196 | * $resolver->addNamespace('my', 'My\OtherPackage\ViewHelpers'); |
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| 197 | * // Now, since ExampleViewHelper exists in both places but the |
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| 198 | * // My\OtherPackage\ViewHelpers namespace was added *last*, Fluid |
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| 199 | * // will find and use My\OtherPackage\ViewHelpers\ExampleViewHelper. |
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| 200 | * |
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| 201 | * Alternatively, setNamespaces() can be used to reset and redefine |
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| 202 | * all previously added namespaces - which is great for cases where |
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| 203 | * you need to remove or replace previously added namespaces. Be aware |
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| 204 | * that setNamespaces() also removes the default "f" namespace, so |
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| 205 | * when you use this method you should always include the "f" namespace. |
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| 206 | * |
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| 207 | * @param string $identifier |
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| 208 | * @param string|array $phpNamespace |
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| 209 | * @return void |
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| 210 | */ |
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| 211 | public function addNamespace(string $identifier, $phpNamespace): void |
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| 222 | |||
| 223 | /** |
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| 224 | * Wrapper to allow adding namespaces in bulk *without* first |
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| 225 | * clearing the already added namespaces. Utility method mainly |
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| 226 | * used in compiled templates, where some namespaces can be added |
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| 227 | * from outside and some can be added from compiled values. |
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| 228 | * |
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| 229 | * @param array $namespaces |
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| 230 | * @return void |
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| 231 | */ |
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| 232 | public function addNamespaces(array $namespaces): void |
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| 238 | |||
| 239 | public function removeNamespace(string $identifier, $phpNamespace): void |
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| 248 | |||
| 249 | /** |
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| 250 | * Resolves the PHP namespace based on the Fluid xmlns namespace, |
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| 251 | * which can be either a URL matching the Patterns::NAMESPACEPREFIX |
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| 252 | * and Patterns::NAMESPACESUFFIX rules, or a PHP namespace. When |
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| 253 | * namespace is a PHP namespace it is optional to suffix it with |
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| 254 | * the "\ViewHelpers" segment, e.g. "My\Package" is as valid to |
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| 255 | * use as "My\Package\ViewHelpers" is. |
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| 256 | * |
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| 257 | * @param string $fluidNamespace |
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| 258 | * @return string |
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| 259 | */ |
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| 260 | public function resolvePhpNamespaceFromFluidNamespace(string $fluidNamespace): string |
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| 278 | |||
| 279 | /** |
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| 280 | * Set all namespaces as an array of ['identifier' => ['Php\Namespace1', 'Php\Namespace2']] |
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| 281 | * namespace definitions. For convenience and legacy support, a |
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| 282 | * format of ['identifier' => 'Only\Php\Namespace'] is allowed, |
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| 283 | * but will internally convert the namespace to an array and |
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| 284 | * allow it to be extended by addNamespace(). |
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| 285 | * |
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| 286 | * Note that when using this method the default "f" namespace is |
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| 287 | * also removed and so must be included in $namespaces or added |
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| 288 | * after using addNamespace(). Or, add the PHP namespaces that |
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| 289 | * belonged to "f" as a new alias and use that in your templates. |
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| 290 | * |
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| 291 | * Use getNamespaces() to get an array of currently added namespaces. |
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| 292 | * |
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| 293 | * @param array $namespaces |
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| 294 | * @return void |
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| 295 | */ |
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| 296 | public function setNamespaces(array $namespaces): void |
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| 303 | |||
| 304 | /** |
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| 305 | * Validates the given namespaceIdentifier and returns FALSE |
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| 306 | * if the namespace is unknown, causing the tag to be rendered |
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| 307 | * without processing. |
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| 308 | * |
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| 309 | * @param string $namespaceIdentifier |
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| 310 | * @return boolean TRUE if the given namespace is valid, otherwise FALSE |
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| 311 | */ |
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| 312 | public function isNamespaceValid(string $namespaceIdentifier): bool |
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| 320 | |||
| 321 | /** |
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| 322 | * Validates the given namespaceIdentifier and returns FALSE |
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| 323 | * if the namespace is unknown and not ignored |
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| 324 | * |
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| 325 | * @param string $namespaceIdentifier |
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| 326 | * @return boolean TRUE if the given namespace is valid, otherwise FALSE |
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| 327 | */ |
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| 328 | public function isNamespaceValidOrIgnored(string $namespaceIdentifier): bool |
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| 339 | |||
| 340 | /** |
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| 341 | * @param string $namespaceIdentifier |
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| 342 | * @return boolean |
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| 343 | */ |
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| 344 | public function isNamespaceIgnored(string $namespaceIdentifier): bool |
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| 360 | |||
| 361 | /** |
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| 362 | * Resolves a ViewHelper class name by namespace alias and |
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| 363 | * Fluid-format identity, e.g. "f" and "format.htmlspecialchars". |
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| 364 | * |
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| 365 | * Looks in all PHP namespaces which have been added for the |
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| 366 | * provided alias, starting in the last added PHP namespace. If |
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| 367 | * a ViewHelper class exists in multiple PHP namespaces Fluid |
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| 368 | * will detect and use whichever one was added last. |
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| 369 | * |
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| 370 | * If no ViewHelper class can be detected in any of the added |
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| 371 | * PHP namespaces a Fluid Parser Exception is thrown. |
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| 372 | * |
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| 373 | * @param string|null $namespaceIdentifier |
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| 374 | * @param string $methodIdentifier |
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| 375 | * @return string|null |
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| 376 | * @throws Exception |
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| 377 | */ |
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| 378 | public function resolveViewHelperClassName(?string $namespaceIdentifier, string $methodIdentifier): ?string |
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| 420 | |||
| 421 | /** |
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| 422 | * Can be overridden by custom implementations to change the way |
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| 423 | * classes are loaded when the class is a ViewHelper - for |
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| 424 | * example making it possible to use a DI-aware class loader. |
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| 425 | * |
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| 426 | * If null is passed as namespace, only registered ViewHelper |
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| 427 | * aliases are checked against the $viewHelperShortName. |
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| 428 | * |
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| 429 | * @param string|null $namespace |
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| 430 | * @param string $viewHelperShortName |
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| 431 | * @return ComponentInterface |
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| 432 | */ |
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| 433 | public function createViewHelperInstance(?string $namespace, string $viewHelperShortName): ComponentInterface |
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| 448 | |||
| 449 | /** |
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| 450 | * Wrapper to create a ViewHelper instance by class name. This is |
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| 451 | * the final method called when creating ViewHelper classes - |
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| 452 | * overriding this method allows custom constructors, dependency |
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| 453 | * injections etc. to be performed on the ViewHelper instance. |
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| 454 | * |
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| 455 | * @param string $viewHelperClassName |
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| 456 | * @return ComponentInterface |
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| 457 | */ |
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| 458 | public function createViewHelperInstanceFromClassName(string $viewHelperClassName): ComponentInterface |
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| 462 | } |
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| 463 |
Let’s assume that you have a directory layout like this:
. |-- OtherDir | |-- Bar.php | `-- Foo.php `-- SomeDir `-- Foo.phpand let’s assume the following content of
Bar.php:If both files
OtherDir/Foo.phpandSomeDir/Foo.phpare loaded in the same runtime, you will see a PHP error such as the following:PHP Fatal error: Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.phpHowever, as
OtherDir/Foo.phpdoes not necessarily have to be loaded and the error is only triggered if it is loaded beforeOtherDir/Bar.php, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias: