silverstripe /
silverstripe-framework
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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| 29 | class ViewableData implements IteratorAggregate |
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| 30 | { |
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| 31 | use Extensible { |
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| 32 | defineMethods as extensibleDefineMethods; |
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| 33 | } |
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| 34 | use Injectable; |
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| 35 | use Configurable; |
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| 36 | |||
| 37 | /** |
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| 38 | * An array of objects to cast certain fields to. This is set up as an array in the format: |
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| 39 | * |
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| 40 | * <code> |
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| 41 | * public static $casting = array ( |
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| 42 | * 'FieldName' => 'ClassToCastTo(Arguments)' |
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| 43 | * ); |
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| 44 | * </code> |
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| 45 | * |
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| 46 | * @var array |
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| 47 | * @config |
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| 48 | */ |
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| 49 | private static $casting = array( |
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| 50 | 'CSSClasses' => 'Varchar' |
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| 51 | ); |
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| 52 | |||
| 53 | /** |
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| 54 | * The default object to cast scalar fields to if casting information is not specified, and casting to an object |
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| 55 | * is required. |
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| 56 | * |
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| 57 | * @var string |
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| 58 | * @config |
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| 59 | */ |
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| 60 | private static $default_cast = 'Text'; |
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| 61 | |||
| 62 | /** |
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| 63 | * @var array |
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| 64 | */ |
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| 65 | private static $casting_cache = array(); |
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| 66 | |||
| 67 | // ----------------------------------------------------------------------------------------------------------------- |
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| 68 | |||
| 69 | /** |
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| 70 | * A failover object to attempt to get data from if it is not present on this object. |
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| 71 | * |
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| 72 | * @var ViewableData |
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| 73 | */ |
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| 74 | protected $failover; |
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| 75 | |||
| 76 | /** |
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| 77 | * @var ViewableData |
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| 78 | */ |
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| 79 | protected $customisedObject; |
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| 80 | |||
| 81 | /** |
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| 82 | * @var array |
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| 83 | */ |
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| 84 | private $objCache = array(); |
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| 85 | |||
| 86 | public function __construct() |
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| 90 | |||
| 91 | // ----------------------------------------------------------------------------------------------------------------- |
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| 92 | |||
| 93 | // FIELD GETTERS & SETTERS ----------------------------------------------------------------------------------------- |
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| 94 | |||
| 95 | /** |
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| 96 | * Check if a field exists on this object or its failover. |
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| 97 | * Note that, unlike the core isset() implementation, this will return true if the property is defined |
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| 98 | * and set to null. |
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| 99 | * |
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| 100 | * @param string $property |
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| 101 | * @return bool |
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| 102 | */ |
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| 103 | public function __isset($property) |
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| 116 | |||
| 117 | /** |
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| 118 | * 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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| 119 | * check if a field is available using {@link ViewableData::getField()}, then fall back on a failover object. |
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| 120 | * |
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| 121 | * @param string $property |
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| 122 | * @return mixed |
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| 123 | */ |
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| 124 | public function __get($property) |
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| 137 | |||
| 138 | /** |
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| 139 | * Set a property/field on this object. This will check for the existence of a method called set{$property}, then |
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| 140 | * use the {@link ViewableData::setField()} method. |
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| 141 | * |
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| 142 | * @param string $property |
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| 143 | * @param mixed $value |
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| 144 | */ |
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| 145 | public function __set($property, $value) |
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| 154 | |||
| 155 | /** |
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| 156 | * Set a failover object to attempt to get data from if it is not present on this object. |
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| 157 | * |
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| 158 | * @param ViewableData $failover |
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| 159 | */ |
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| 160 | public function setFailover(ViewableData $failover) |
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| 170 | |||
| 171 | /** |
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| 172 | * Get the current failover object if set |
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| 173 | * |
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| 174 | * @return ViewableData|null |
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| 175 | */ |
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| 176 | public function getFailover() |
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| 180 | |||
| 181 | /** |
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| 182 | * Check if a field exists on this object. This should be overloaded in child classes. |
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| 183 | * |
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| 184 | * @param string $field |
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| 185 | * @return bool |
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| 186 | */ |
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| 187 | public function hasField($field) |
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| 191 | |||
| 192 | /** |
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| 193 | * Get the value of a field on this object. This should be overloaded in child classes. |
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| 194 | * |
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| 195 | * @param string $field |
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| 196 | * @return mixed |
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| 197 | */ |
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| 198 | public function getField($field) |
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| 202 | |||
| 203 | /** |
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| 204 | * Set a field on this object. This should be overloaded in child classes. |
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| 205 | * |
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| 206 | * @param string $field |
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| 207 | * @param mixed $value |
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| 208 | * @return $this |
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| 209 | */ |
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| 210 | public function setField($field, $value) |
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| 216 | |||
| 217 | // ----------------------------------------------------------------------------------------------------------------- |
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| 218 | |||
| 219 | /** |
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| 220 | * Add methods from the {@link ViewableData::$failover} object, as well as wrapping any methods prefixed with an |
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| 221 | * underscore into a {@link ViewableData::cachedCall()}. |
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| 222 | * |
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| 223 | * @throws LogicException |
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| 224 | */ |
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| 225 | public function defineMethods() |
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| 241 | |||
| 242 | /** |
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| 243 | * Merge some arbitrary data in with this object. This method returns a {@link ViewableData_Customised} instance |
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| 244 | * with references to both this and the new custom data. |
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| 245 | * |
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| 246 | * Note that any fields you specify will take precedence over the fields on this object. |
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| 247 | * |
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| 248 | * @param array|ViewableData $data |
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| 249 | * @return ViewableData_Customised |
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| 250 | */ |
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| 251 | public function customise($data) |
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| 265 | |||
| 266 | /** |
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| 267 | * Return true if this object "exists" i.e. has a sensible value |
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| 268 | * |
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| 269 | * This method should be overriden in subclasses to provide more context about the classes state. For example, a |
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| 270 | * {@link DataObject} class could return false when it is deleted from the database |
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| 271 | * |
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| 272 | * @return bool |
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| 273 | */ |
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| 274 | public function exists() |
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| 278 | |||
| 279 | /** |
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| 280 | * @return string the class name |
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| 281 | */ |
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| 282 | public function __toString() |
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| 286 | |||
| 287 | /** |
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| 288 | * @return ViewableData |
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| 289 | */ |
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| 290 | public function getCustomisedObj() |
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| 294 | |||
| 295 | /** |
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| 296 | * @param ViewableData $object |
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| 297 | */ |
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| 298 | public function setCustomisedObj(ViewableData $object) |
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| 302 | |||
| 303 | // CASTING --------------------------------------------------------------------------------------------------------- |
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| 304 | |||
| 305 | /** |
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| 306 | * Return the "casting helper" (a piece of PHP code that when evaluated creates a casted value object) |
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| 307 | * for a field on this object. This helper will be a subclass of DBField. |
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| 308 | * |
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| 309 | * @param string $field |
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| 310 | * @return string Casting helper As a constructor pattern, and may include arguments. |
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| 311 | * @throws Exception |
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| 312 | */ |
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| 313 | public function castingHelper($field) |
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| 338 | |||
| 339 | /** |
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| 340 | * Get the class name a field on this object will be casted to. |
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| 341 | * |
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| 342 | * @param string $field |
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| 343 | * @return string |
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| 344 | */ |
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| 345 | public function castingClass($field) |
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| 351 | |||
| 352 | /** |
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| 353 | * Return the string-format type for the given field. |
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| 354 | * |
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| 355 | * @param string $field |
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| 356 | * @return string 'xml'|'raw' |
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| 357 | */ |
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| 358 | public function escapeTypeForField($field) |
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| 368 | |||
| 369 | // TEMPLATE ACCESS LAYER ------------------------------------------------------------------------------------------- |
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| 370 | |||
| 371 | /** |
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| 372 | * 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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| 373 | * $template parameter: |
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| 374 | * - a template name (e.g. Page) |
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| 375 | * - an array of possible template names - the first valid one will be used |
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| 376 | * - an SSViewer instance |
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| 377 | * |
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| 378 | * @param string|array|SSViewer $template the template to render into |
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| 379 | * @param array $customFields fields to customise() the object with before rendering |
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| 380 | * @return DBHTMLText |
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| 381 | */ |
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| 382 | public function renderWith($template, $customFields = null) |
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| 401 | |||
| 402 | /** |
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| 403 | * Generate the cache name for a field |
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| 404 | * |
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| 405 | * @param string $fieldName Name of field |
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| 406 | * @param array $arguments List of optional arguments given |
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| 407 | * @return string |
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| 408 | */ |
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| 409 | protected function objCacheName($fieldName, $arguments) |
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| 415 | |||
| 416 | /** |
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| 417 | * Get a cached value from the field cache |
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| 418 | * |
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| 419 | * @param string $key Cache key |
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| 420 | * @return mixed |
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| 421 | */ |
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| 422 | protected function objCacheGet($key) |
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| 429 | |||
| 430 | /** |
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| 431 | * Store a value in the field cache |
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| 432 | * |
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| 433 | * @param string $key Cache key |
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| 434 | * @param mixed $value |
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| 435 | * @return $this |
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| 436 | */ |
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| 437 | protected function objCacheSet($key, $value) |
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| 442 | |||
| 443 | /** |
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| 444 | * Clear object cache |
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| 445 | * |
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| 446 | * @return $this |
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| 447 | */ |
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| 448 | protected function objCacheClear() |
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| 453 | |||
| 454 | /** |
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| 455 | * Get the value of a field on this object, automatically inserting the value into any available casting objects |
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| 456 | * that have been specified. |
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| 457 | * |
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| 458 | * @param string $fieldName |
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| 459 | * @param array $arguments |
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| 460 | * @param bool $cache Cache this object |
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| 461 | * @param string $cacheName a custom cache name |
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| 462 | * @return Object|DBField |
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| 463 | */ |
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| 464 | public function obj($fieldName, $arguments = [], $cache = false, $cacheName = null) |
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| 499 | |||
| 500 | /** |
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| 501 | * A simple wrapper around {@link ViewableData::obj()} that automatically caches the result so it can be used again |
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| 502 | * without re-running the method. |
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| 503 | * |
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| 504 | * @param string $field |
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| 505 | * @param array $arguments |
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| 506 | * @param string $identifier an optional custom cache identifier |
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| 507 | * @return Object|DBField |
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| 508 | */ |
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| 509 | public function cachedCall($field, $arguments = [], $identifier = null) |
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| 513 | |||
| 514 | /** |
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| 515 | * 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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| 516 | * exists method, otherwise will check if the result is not just an empty paragraph tag. |
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| 517 | * |
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| 518 | * @param string $field |
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| 519 | * @param array $arguments |
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| 520 | * @param bool $cache |
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| 521 | * @return bool |
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| 522 | */ |
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| 523 | public function hasValue($field, $arguments = [], $cache = true) |
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| 528 | |||
| 529 | /** |
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| 530 | * 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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| 531 | * template. |
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| 532 | * |
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| 533 | * @param string $field |
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| 534 | * @param array $arguments |
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| 535 | * @param bool $cache |
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| 536 | * @return string |
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| 537 | */ |
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| 538 | public function XML_val($field, $arguments = [], $cache = false) |
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| 544 | |||
| 545 | /** |
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| 546 | * Get an array of XML-escaped values by field name |
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| 547 | * |
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| 548 | * @param array $fields an array of field names |
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| 549 | * @return array |
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| 550 | */ |
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| 551 | public function getXMLValues($fields) |
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| 561 | |||
| 562 | // ITERATOR SUPPORT ------------------------------------------------------------------------------------------------ |
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| 563 | |||
| 564 | /** |
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| 565 | * Return a single-item iterator so you can iterate over the fields of a single record. |
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| 566 | * |
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| 567 | * This is useful so you can use a single record inside a <% control %> block in a template - and then use |
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| 568 | * to access individual fields on this object. |
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| 569 | * |
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| 570 | * @return ArrayIterator |
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| 571 | */ |
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| 572 | public function getIterator() |
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| 576 | |||
| 577 | // UTILITY METHODS ------------------------------------------------------------------------------------------------- |
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| 578 | |||
| 579 | /** |
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| 580 | * When rendering some objects it is necessary to iterate over the object being rendered, to do this, you need |
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| 581 | * access to itself. |
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| 582 | * |
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| 583 | * @return ViewableData |
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| 584 | */ |
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| 585 | public function Me() |
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| 589 | |||
| 590 | /** |
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| 591 | * Get part of the current classes ancestry to be used as a CSS class. |
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| 592 | * |
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| 593 | * This method returns an escaped string of CSS classes representing the current classes ancestry until it hits a |
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| 594 | * stop point - e.g. "Page DataObject ViewableData". |
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| 595 | * |
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| 596 | * @param string $stopAtClass the class to stop at (default: ViewableData) |
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| 597 | * @return string |
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| 598 | * @uses ClassInfo |
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| 599 | */ |
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| 600 | public function CSSClasses($stopAtClass = self::class) |
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| 623 | |||
| 624 | /** |
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| 625 | * Return debug information about this object that can be rendered into a template |
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| 626 | * |
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| 627 | * @return ViewableData_Debugger |
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| 628 | */ |
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| 629 | public function Debug() |
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| 633 | } |
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| 634 |
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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: