Complex classes like ViewableData 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 ViewableData, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 26 | class ViewableData extends Object implements IteratorAggregate |
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| 27 | { |
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| 28 | |||
| 29 | /** |
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| 30 | * An array of objects to cast certain fields to. This is set up as an array in the format: |
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| 31 | * |
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| 32 | * <code> |
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| 33 | * public static $casting = array ( |
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| 34 | * 'FieldName' => 'ClassToCastTo(Arguments)' |
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| 35 | * ); |
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| 36 | * </code> |
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| 37 | * |
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| 38 | * @var array |
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| 39 | * @config |
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| 40 | */ |
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| 41 | private static $casting = array( |
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| 42 | 'CSSClasses' => 'Varchar' |
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| 43 | ); |
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| 44 | |||
| 45 | /** |
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| 46 | * The default object to cast scalar fields to if casting information is not specified, and casting to an object |
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| 47 | * is required. |
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| 48 | * |
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| 49 | * @var string |
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| 50 | * @config |
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| 51 | */ |
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| 52 | private static $default_cast = 'Text'; |
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| 53 | |||
| 54 | /** |
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| 55 | * @var array |
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| 56 | */ |
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| 57 | private static $casting_cache = array(); |
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| 58 | |||
| 59 | // ----------------------------------------------------------------------------------------------------------------- |
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| 60 | |||
| 61 | /** |
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| 62 | * A failover object to attempt to get data from if it is not present on this object. |
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| 63 | * |
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| 64 | * @var ViewableData |
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| 65 | */ |
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| 66 | protected $failover; |
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| 67 | |||
| 68 | /** |
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| 69 | * @var ViewableData |
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| 70 | */ |
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| 71 | protected $customisedObject; |
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| 72 | |||
| 73 | /** |
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| 74 | * @var array |
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| 75 | */ |
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| 76 | private $objCache = array(); |
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| 77 | |||
| 78 | // ----------------------------------------------------------------------------------------------------------------- |
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| 79 | |||
| 80 | // FIELD GETTERS & SETTERS ----------------------------------------------------------------------------------------- |
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| 81 | |||
| 82 | /** |
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| 83 | * Check if a field exists on this object or its failover. |
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| 84 | * Note that, unlike the core isset() implementation, this will return true if the property is defined |
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| 85 | * and set to null. |
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| 86 | * |
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| 87 | * @param string $property |
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| 88 | * @return bool |
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| 89 | */ |
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| 90 | public function __isset($property) |
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| 103 | |||
| 104 | /** |
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| 105 | * Get the value of a property/field on this object. This will check if a method called get{$property} exists, then |
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| 106 | * check if a field is available using {@link ViewableData::getField()}, then fall back on a failover object. |
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| 107 | * |
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| 108 | * @param string $property |
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| 109 | * @return mixed |
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| 110 | */ |
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| 111 | public function __get($property) |
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| 124 | |||
| 125 | /** |
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| 126 | * Set a property/field on this object. This will check for the existence of a method called set{$property}, then |
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| 127 | * use the {@link ViewableData::setField()} method. |
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| 128 | * |
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| 129 | * @param string $property |
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| 130 | * @param mixed $value |
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| 131 | */ |
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| 132 | public function __set($property, $value) |
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| 141 | |||
| 142 | /** |
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| 143 | * Set a failover object to attempt to get data from if it is not present on this object. |
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| 144 | * |
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| 145 | * @param ViewableData $failover |
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| 146 | */ |
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| 147 | public function setFailover(ViewableData $failover) |
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| 157 | |||
| 158 | /** |
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| 159 | * Get the current failover object if set |
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| 160 | * |
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| 161 | * @return ViewableData|null |
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| 162 | */ |
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| 163 | public function getFailover() |
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| 167 | |||
| 168 | /** |
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| 169 | * Check if a field exists on this object. This should be overloaded in child classes. |
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| 170 | * |
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| 171 | * @param string $field |
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| 172 | * @return bool |
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| 173 | */ |
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| 174 | public function hasField($field) |
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| 178 | |||
| 179 | /** |
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| 180 | * Get the value of a field on this object. This should be overloaded in child classes. |
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| 181 | * |
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| 182 | * @param string $field |
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| 183 | * @return mixed |
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| 184 | */ |
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| 185 | public function getField($field) |
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| 189 | |||
| 190 | /** |
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| 191 | * Set a field on this object. This should be overloaded in child classes. |
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| 192 | * |
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| 193 | * @param string $field |
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| 194 | * @param mixed $value |
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| 195 | * @return $this |
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| 196 | */ |
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| 197 | public function setField($field, $value) |
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| 203 | |||
| 204 | // ----------------------------------------------------------------------------------------------------------------- |
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| 205 | |||
| 206 | /** |
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| 207 | * Add methods from the {@link ViewableData::$failover} object, as well as wrapping any methods prefixed with an |
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| 208 | * underscore into a {@link ViewableData::cachedCall()}. |
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| 209 | * |
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| 210 | * @throws LogicException |
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| 211 | */ |
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| 212 | public function defineMethods() |
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| 227 | |||
| 228 | /** |
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| 229 | * Merge some arbitrary data in with this object. This method returns a {@link ViewableData_Customised} instance |
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| 230 | * with references to both this and the new custom data. |
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| 231 | * |
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| 232 | * Note that any fields you specify will take precedence over the fields on this object. |
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| 233 | * |
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| 234 | * @param array|ViewableData $data |
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| 235 | * @return ViewableData_Customised |
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| 236 | */ |
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| 237 | public function customise($data) |
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| 251 | |||
| 252 | /** |
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| 253 | * @return ViewableData |
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| 254 | */ |
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| 255 | public function getCustomisedObj() |
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| 259 | |||
| 260 | /** |
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| 261 | * @param ViewableData $object |
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| 262 | */ |
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| 263 | public function setCustomisedObj(ViewableData $object) |
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| 267 | |||
| 268 | // CASTING --------------------------------------------------------------------------------------------------------- |
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| 269 | |||
| 270 | /** |
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| 271 | * Return the "casting helper" (a piece of PHP code that when evaluated creates a casted value object) |
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| 272 | * for a field on this object. This helper will be a subclass of DBField. |
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| 273 | * |
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| 274 | * @param string $field |
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| 275 | * @return string Casting helper As a constructor pattern, and may include arguments. |
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| 276 | */ |
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| 277 | public function castingHelper($field) |
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| 302 | |||
| 303 | /** |
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| 304 | * Get the class name a field on this object will be casted to. |
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| 305 | * |
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| 306 | * @param string $field |
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| 307 | * @return string |
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| 308 | */ |
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| 309 | public function castingClass($field) |
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| 315 | |||
| 316 | /** |
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| 317 | * Return the string-format type for the given field. |
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| 318 | * |
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| 319 | * @param string $field |
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| 320 | * @return string 'xml'|'raw' |
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| 321 | */ |
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| 322 | public function escapeTypeForField($field) |
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| 332 | |||
| 333 | // TEMPLATE ACCESS LAYER ------------------------------------------------------------------------------------------- |
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| 334 | |||
| 335 | /** |
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| 336 | * Render this object into the template, and get the result as a string. You can pass one of the following as the |
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| 337 | * $template parameter: |
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| 338 | * - a template name (e.g. Page) |
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| 339 | * - an array of possible template names - the first valid one will be used |
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| 340 | * - an SSViewer instance |
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| 341 | * |
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| 342 | * @param string|array|SSViewer $template the template to render into |
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| 343 | * @param array $customFields fields to customise() the object with before rendering |
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| 344 | * @return DBHTMLText |
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| 345 | */ |
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| 346 | public function renderWith($template, $customFields = null) |
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| 365 | |||
| 366 | /** |
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| 367 | * Generate the cache name for a field |
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| 368 | * |
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| 369 | * @param string $fieldName Name of field |
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| 370 | * @param array $arguments List of optional arguments given |
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| 371 | * @return string |
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| 372 | */ |
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| 373 | protected function objCacheName($fieldName, $arguments) |
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| 379 | |||
| 380 | /** |
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| 381 | * Get a cached value from the field cache |
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| 382 | * |
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| 383 | * @param string $key Cache key |
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| 384 | * @return mixed |
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| 385 | */ |
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| 386 | protected function objCacheGet($key) |
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| 393 | |||
| 394 | /** |
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| 395 | * Store a value in the field cache |
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| 396 | * |
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| 397 | * @param string $key Cache key |
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| 398 | * @param mixed $value |
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| 399 | * @return $this |
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| 400 | */ |
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| 401 | protected function objCacheSet($key, $value) |
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| 406 | |||
| 407 | /** |
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| 408 | * Clear object cache |
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| 409 | * |
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| 410 | * @return $this |
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| 411 | */ |
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| 412 | protected function objCacheClear() |
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| 417 | |||
| 418 | /** |
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| 419 | * Get the value of a field on this object, automatically inserting the value into any available casting objects |
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| 420 | * that have been specified. |
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| 421 | * |
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| 422 | * @param string $fieldName |
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| 423 | * @param array $arguments |
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| 424 | * @param bool $cache Cache this object |
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| 425 | * @param string $cacheName a custom cache name |
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| 426 | * @return Object|DBField |
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| 427 | */ |
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| 428 | public function obj($fieldName, $arguments = [], $cache = false, $cacheName = null) |
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| 463 | |||
| 464 | /** |
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| 465 | * A simple wrapper around {@link ViewableData::obj()} that automatically caches the result so it can be used again |
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| 466 | * without re-running the method. |
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| 467 | * |
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| 468 | * @param string $field |
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| 469 | * @param array $arguments |
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| 470 | * @param string $identifier an optional custom cache identifier |
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| 471 | * @return Object|DBField |
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| 472 | */ |
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| 473 | public function cachedCall($field, $arguments = [], $identifier = null) |
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| 477 | |||
| 478 | /** |
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| 479 | * Checks if a given method/field has a valid value. If the result is an object, this will return the result of the |
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| 480 | * exists method, otherwise will check if the result is not just an empty paragraph tag. |
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| 481 | * |
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| 482 | * @param string $field |
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| 483 | * @param array $arguments |
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| 484 | * @param bool $cache |
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| 485 | * @return bool |
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| 486 | */ |
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| 487 | public function hasValue($field, $arguments = [], $cache = true) |
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| 492 | |||
| 493 | /** |
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| 494 | * Get the string value of a field on this object that has been suitable escaped to be inserted directly into a |
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| 495 | * template. |
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| 496 | * |
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| 497 | * @param string $field |
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| 498 | * @param array $arguments |
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| 499 | * @param bool $cache |
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| 500 | * @return string |
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| 501 | */ |
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| 502 | public function XML_val($field, $arguments = [], $cache = false) |
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| 508 | |||
| 509 | /** |
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| 510 | * Get an array of XML-escaped values by field name |
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| 511 | * |
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| 512 | * @param array $fields an array of field names |
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| 513 | * @return array |
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| 514 | */ |
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| 515 | public function getXMLValues($fields) |
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| 525 | |||
| 526 | // ITERATOR SUPPORT ------------------------------------------------------------------------------------------------ |
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| 527 | |||
| 528 | /** |
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| 529 | * Return a single-item iterator so you can iterate over the fields of a single record. |
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| 530 | * |
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| 531 | * This is useful so you can use a single record inside a <% control %> block in a template - and then use |
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| 532 | * to access individual fields on this object. |
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| 533 | * |
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| 534 | * @return ArrayIterator |
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| 535 | */ |
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| 536 | public function getIterator() |
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| 540 | |||
| 541 | // UTILITY METHODS ------------------------------------------------------------------------------------------------- |
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| 542 | |||
| 543 | /** |
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| 544 | * When rendering some objects it is necessary to iterate over the object being rendered, to do this, you need |
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| 545 | * access to itself. |
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| 546 | * |
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| 547 | * @return ViewableData |
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| 548 | */ |
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| 549 | public function Me() |
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| 553 | |||
| 554 | /** |
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| 555 | * Get part of the current classes ancestry to be used as a CSS class. |
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| 556 | * |
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| 557 | * This method returns an escaped string of CSS classes representing the current classes ancestry until it hits a |
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| 558 | * stop point - e.g. "Page DataObject ViewableData". |
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| 559 | * |
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| 560 | * @param string $stopAtClass the class to stop at (default: ViewableData) |
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| 561 | * @return string |
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| 562 | * @uses ClassInfo |
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| 563 | */ |
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| 564 | public function CSSClasses($stopAtClass = 'SilverStripe\\View\\ViewableData') |
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| 587 | |||
| 588 | /** |
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| 589 | * Return debug information about this object that can be rendered into a template |
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| 590 | * |
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| 591 | * @return ViewableData_Debugger |
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| 592 | */ |
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| 593 | public function Debug() |
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| 597 | } |
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| 598 |
Instead of super-globals, we recommend to explicitly inject the dependencies of your class. This makes your code less dependent on global state and it becomes generally more testable: