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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| 15 | class ViewableData extends Object implements IteratorAggregate { | 
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| 16 | |||
| 17 | /**  | 
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| 18 | * An array of objects to cast certain fields to. This is set up as an array in the format:  | 
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| 19 | *  | 
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| 20 | * <code>  | 
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| 21 | * public static $casting = array (  | 
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| 22 | * 'FieldName' => 'ClassToCastTo(Arguments)'  | 
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| 23 | * );  | 
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| 24 | * </code>  | 
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| 25 | *  | 
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| 26 | * @var array  | 
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| 27 | * @config  | 
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| 28 | */  | 
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| 29 | private static $casting = array(  | 
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| 30 | 'CSSClasses' => 'Varchar'  | 
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| 31 | );  | 
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| 32 | |||
| 33 | /**  | 
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| 34 | * The default object to cast scalar fields to if casting information is not specified, and casting to an object  | 
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| 35 | * is required.  | 
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| 36 | *  | 
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| 37 | * @var string  | 
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| 38 | * @config  | 
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| 39 | */  | 
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| 40 | private static $default_cast = 'Text';  | 
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| 41 | |||
| 42 | /**  | 
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| 43 | * @var array  | 
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| 44 | */  | 
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| 45 | private static $casting_cache = array();  | 
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| 46 | |||
| 47 | // -----------------------------------------------------------------------------------------------------------------  | 
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| 48 | |||
| 49 | /**  | 
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| 50 | * A failover object to attempt to get data from if it is not present on this object.  | 
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| 51 | *  | 
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| 52 | * @var ViewableData  | 
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| 53 | */  | 
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| 54 | protected $failover;  | 
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| 55 | |||
| 56 | /**  | 
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| 57 | * @var ViewableData  | 
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| 58 | */  | 
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| 59 | protected $customisedObject;  | 
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| 60 | |||
| 61 | /**  | 
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| 62 | * @var array  | 
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| 63 | */  | 
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| 64 | private $objCache = array();  | 
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| 65 | |||
| 66 | // -----------------------------------------------------------------------------------------------------------------  | 
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| 67 | |||
| 68 | /**  | 
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| 69 | * Converts a field spec into an object creator. For example: "Int" becomes "new Int($fieldName);" and "Varchar(50)"  | 
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| 70 | * becomes "new DBVarchar($fieldName, 50);".  | 
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| 71 | *  | 
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| 72 | * @param string $fieldSchema The field spec  | 
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| 73 | * @return string  | 
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| 74 | */  | 
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| 75 | 	public static function castingObjectCreator($fieldSchema) { | 
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| 78 | |||
| 79 | /**  | 
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| 80 | * Convert a field schema (e.g. "Varchar(50)") into a casting object creator array that contains both a className  | 
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| 81 | 	 * and castingHelper constructor code. See {@link castingObjectCreator} for more information about the constructor. | 
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| 82 | *  | 
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| 83 | * @param string $fieldSchema  | 
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| 84 | * @return array  | 
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| 85 | */  | 
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| 86 | 	public static function castingObjectCreatorPair($fieldSchema) { | 
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| 89 | |||
| 90 | // FIELD GETTERS & SETTERS -----------------------------------------------------------------------------------------  | 
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| 91 | |||
| 92 | /**  | 
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| 93 | * Check if a field exists on this object or its failover.  | 
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| 94 | *  | 
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| 95 | * @param string $property  | 
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| 96 | * @return bool  | 
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| 97 | */  | 
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| 98 | 	public function __isset($property) { | 
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| 101 | |||
| 102 | /**  | 
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| 103 | 	 * 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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| 104 | 	 * check if a field is available using {@link ViewableData::getField()}, then fall back on a failover object. | 
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| 105 | *  | 
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| 106 | * @param string $property  | 
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| 107 | * @return mixed  | 
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| 108 | */  | 
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| 109 | 	public function __get($property) { | 
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| 118 | |||
| 119 | /**  | 
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| 120 | 	 * Set a property/field on this object. This will check for the existence of a method called set{$property}, then | 
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| 121 | 	 * use the {@link ViewableData::setField()} method. | 
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| 122 | *  | 
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| 123 | * @param string $property  | 
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| 124 | * @param mixed $value  | 
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| 125 | */  | 
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| 126 | 	public function __set($property, $value) { | 
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| 133 | |||
| 134 | /**  | 
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| 135 | * Set a failover object to attempt to get data from if it is not present on this object.  | 
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| 136 | *  | 
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| 137 | * @param ViewableData $failover  | 
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| 138 | */  | 
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| 139 | 	public function setFailover(ViewableData $failover) { | 
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| 143 | |||
| 144 | /**  | 
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| 145 | * Get the current failover object if set  | 
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| 146 | *  | 
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| 147 | * @return ViewableData|null  | 
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| 148 | */  | 
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| 149 | 	public function getFailover() { | 
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| 152 | |||
| 153 | /**  | 
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| 154 | * Check if a field exists on this object. This should be overloaded in child classes.  | 
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| 155 | *  | 
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| 156 | * @param string $field  | 
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| 157 | * @return bool  | 
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| 158 | */  | 
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| 159 | 	public function hasField($field) { | 
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| 162 | |||
| 163 | /**  | 
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| 164 | * Get the value of a field on this object. This should be overloaded in child classes.  | 
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| 165 | *  | 
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| 166 | * @param string $field  | 
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| 167 | * @return mixed  | 
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| 168 | */  | 
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| 169 | 	public function getField($field) { | 
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| 172 | |||
| 173 | /**  | 
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| 174 | * Set a field on this object. This should be overloaded in child classes.  | 
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| 175 | *  | 
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| 176 | * @param string $field  | 
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| 177 | * @param mixed $value  | 
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| 178 | */  | 
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| 179 | 	public function setField($field, $value) { | 
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| 182 | |||
| 183 | // -----------------------------------------------------------------------------------------------------------------  | 
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| 184 | |||
| 185 | /**  | 
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| 186 | 	 * Add methods from the {@link ViewableData::$failover} object, as well as wrapping any methods prefixed with an | 
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| 187 | 	 * underscore into a {@link ViewableData::cachedCall()}. | 
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| 188 | */  | 
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| 189 | 	public function defineMethods() { | 
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| 201 | |||
| 202 | /**  | 
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| 203 | 	 * Merge some arbitrary data in with this object. This method returns a {@link ViewableData_Customised} instance | 
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| 204 | * with references to both this and the new custom data.  | 
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| 205 | *  | 
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| 206 | * Note that any fields you specify will take precedence over the fields on this object.  | 
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| 207 | *  | 
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| 208 | * @param array|ViewableData $data  | 
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| 209 | * @return ViewableData_Customised  | 
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| 210 | */  | 
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| 211 | 	public function customise($data) { | 
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| 224 | |||
| 225 | /**  | 
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| 226 | * @return ViewableData  | 
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| 227 | */  | 
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| 228 | 	public function getCustomisedObj() { | 
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| 231 | |||
| 232 | /**  | 
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| 233 | * @param ViewableData $object  | 
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| 234 | */  | 
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| 235 | 	public function setCustomisedObj(ViewableData $object) { | 
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| 238 | |||
| 239 | // CASTING ---------------------------------------------------------------------------------------------------------  | 
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| 240 | |||
| 241 | /**  | 
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| 242 | * Get the class a field on this object would be casted to, as well as the casting helper for casting a field to  | 
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| 243 | 	 * an object (see {@link ViewableData::castingHelper()} for information on casting helpers). | 
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| 244 | *  | 
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| 245 | * The returned array contains two keys:  | 
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| 246 | * - className: the class the field would be casted to (e.g. "Varchar")  | 
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| 247 | * - castingHelper: the casting helper for casting the field (e.g. "return new Varchar($fieldName)")  | 
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| 248 | *  | 
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| 249 | * @param string $field  | 
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| 250 | * @return array  | 
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| 251 | */  | 
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| 252 | 	public function castingHelperPair($field) { | 
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| 256 | |||
| 257 | /**  | 
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| 258 | * Return the "casting helper" (a piece of PHP code that when evaluated creates a casted value object) for a field  | 
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| 259 | * on this object.  | 
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| 260 | *  | 
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| 261 | * @param string $field  | 
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| 262 | * @return string Casting helper  | 
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| 263 | */  | 
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| 264 | 	public function castingHelper($field) { | 
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| 272 | |||
| 273 | /**  | 
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| 274 | * Get the class name a field on this object will be casted to  | 
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| 275 | *  | 
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| 276 | * @param string $field  | 
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| 277 | * @return string  | 
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| 278 | */  | 
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| 279 | 	public function castingClass($field) { | 
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| 287 | |||
| 288 | /**  | 
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| 289 | * Return the string-format type for the given field.  | 
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| 290 | *  | 
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| 291 | * @param string $field  | 
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| 292 | * @return string 'xml'|'raw'  | 
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| 293 | */  | 
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| 294 | 	public function escapeTypeForField($field) { | 
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| 301 | |||
| 302 | /**  | 
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| 303 | * Save the casting cache for this object (including data from any failovers) into a variable  | 
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| 304 | *  | 
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| 305 | * @param reference $cache  | 
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| 306 | */  | 
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| 307 | 	public function buildCastingCache(&$cache) { | 
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| 330 | |||
| 331 | // TEMPLATE ACCESS LAYER -------------------------------------------------------------------------------------------  | 
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| 332 | |||
| 333 | /**  | 
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| 334 | * 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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| 335 | * $template parameter:  | 
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| 336 | * - a template name (e.g. Page)  | 
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| 337 | * - an array of possible template names - the first valid one will be used  | 
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| 338 | * - an SSViewer instance  | 
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| 339 | *  | 
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| 340 | * @param string|array|SSViewer $template the template to render into  | 
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| 341 | * @param array $customFields fields to customise() the object with before rendering  | 
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| 342 | * @return HTMLText  | 
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| 343 | */  | 
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| 344 | 	public function renderWith($template, $customFields = null) { | 
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| 362 | |||
| 363 | /**  | 
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| 364 | * Generate the cache name for a field  | 
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| 365 | *  | 
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| 366 | * @param string $fieldName Name of field  | 
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| 367 | * @param array $arguments List of optional arguments given  | 
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| 368 | */  | 
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| 369 | 	protected function objCacheName($fieldName, $arguments) { | 
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| 374 | |||
| 375 | /**  | 
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| 376 | * Get a cached value from the field cache  | 
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| 377 | *  | 
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| 378 | * @param string $key Cache key  | 
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| 379 | * @return mixed  | 
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| 380 | */  | 
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| 381 | 	protected function objCacheGet($key) { | 
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| 384 | |||
| 385 | /**  | 
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| 386 | * Store a value in the field cache  | 
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| 387 | *  | 
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| 388 | * @param string $key Cache key  | 
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| 389 | * @param mixed $value  | 
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| 390 | */  | 
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| 391 | 	protected function objCacheSet($key, $value) { | 
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| 394 | |||
| 395 | /**  | 
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| 396 | * Get the value of a field on this object, automatically inserting the value into any available casting objects  | 
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| 397 | * that have been specified.  | 
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| 398 | *  | 
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| 399 | * @param string $fieldName  | 
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| 400 | * @param array $arguments  | 
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| 401 | * @param bool $forceReturnedObject if TRUE, the value will ALWAYS be casted to an object before being returned,  | 
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| 402 | * even if there is no explicit casting information  | 
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| 403 | * @param bool $cache Cache this object  | 
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| 404 | * @param string $cacheName a custom cache name  | 
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| 405 | */  | 
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| 406 | 	public function obj($fieldName, $arguments = null, $forceReturnedObject = true, $cache = false, $cacheName = null) { | 
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| 444 | |||
| 445 | /**  | 
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| 446 | 	 * A simple wrapper around {@link ViewableData::obj()} that automatically caches the result so it can be used again | 
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| 447 | * without re-running the method.  | 
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| 448 | *  | 
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| 449 | * @param string $field  | 
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| 450 | * @param array $arguments  | 
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| 451 | * @param string $identifier an optional custom cache identifier  | 
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| 452 | */  | 
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| 453 | 	public function cachedCall($field, $arguments = null, $identifier = null) { | 
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| 456 | |||
| 457 | /**  | 
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| 458 | * 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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| 459 | * exists method, otherwise will check if the result is not just an empty paragraph tag.  | 
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| 460 | *  | 
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| 461 | * @param string $field  | 
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| 462 | * @param array $arguments  | 
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| 463 | * @param bool $cache  | 
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| 464 | * @return bool  | 
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| 465 | */  | 
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| 466 | 	public function hasValue($field, $arguments = null, $cache = true) { | 
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| 476 | |||
| 477 | /**#@+  | 
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| 478 | * @param string $field  | 
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| 479 | * @param array $arguments  | 
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| 480 | * @param bool $cache  | 
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| 481 | * @return string  | 
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| 482 | */  | 
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| 483 | |||
| 484 | /**  | 
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| 485 | * Get the string value of a field on this object that has been suitable escaped to be inserted directly into a  | 
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| 486 | * template.  | 
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| 487 | */  | 
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| 488 | 	public function XML_val($field, $arguments = null, $cache = false) { | 
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| 492 | |||
| 493 | /**  | 
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| 494 | * Return the value of the field without any escaping being applied.  | 
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| 495 | */  | 
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| 496 | 	public function RAW_val($field, $arguments = null, $cache = true) { | 
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| 499 | |||
| 500 | /**  | 
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| 501 | * Return the value of a field in an SQL-safe format.  | 
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| 502 | */  | 
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| 503 | 	public function SQL_val($field, $arguments = null, $cache = true) { | 
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| 506 | |||
| 507 | /**  | 
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| 508 | * Return the value of a field in a JavaScript-save format.  | 
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| 509 | */  | 
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| 510 | 	public function JS_val($field, $arguments = null, $cache = true) { | 
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| 513 | |||
| 514 | /**  | 
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| 515 | * Return the value of a field escaped suitable to be inserted into an XML node attribute.  | 
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| 516 | */  | 
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| 517 | 	public function ATT_val($field, $arguments = null, $cache = true) { | 
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| 520 | |||
| 521 | /**#@-*/  | 
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| 522 | |||
| 523 | /**  | 
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| 524 | * Get an array of XML-escaped values by field name  | 
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| 525 | *  | 
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| 526 | * @param array $elements an array of field names  | 
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| 527 | * @return array  | 
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| 528 | */  | 
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| 529 | 	public function getXMLValues($fields) { | 
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| 538 | |||
| 539 | // ITERATOR SUPPORT ------------------------------------------------------------------------------------------------  | 
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| 540 | |||
| 541 | /**  | 
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| 542 | * Return a single-item iterator so you can iterate over the fields of a single record.  | 
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| 543 | *  | 
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| 544 | * This is useful so you can use a single record inside a <% control %> block in a template - and then use  | 
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| 545 | * to access individual fields on this object.  | 
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| 546 | *  | 
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| 547 | * @return ArrayIterator  | 
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| 548 | */  | 
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| 549 | 	public function getIterator() { | 
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| 552 | |||
| 553 | // UTILITY METHODS -------------------------------------------------------------------------------------------------  | 
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| 554 | |||
| 555 | /**  | 
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| 556 | * When rendering some objects it is necessary to iterate over the object being rendered, to do this, you need  | 
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| 557 | * access to itself.  | 
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| 558 | *  | 
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| 559 | * @return ViewableData  | 
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| 560 | */  | 
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| 561 | 	public function Me() { | 
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| 564 | |||
| 565 | /**  | 
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| 566 | * Return the directory if the current active theme (relative to the site root).  | 
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| 567 | *  | 
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| 568 | * This method is useful for things such as accessing theme images from your template without hardcoding the theme  | 
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| 569 | * page - e.g. <img src="$ThemeDir/images/something.gif">.  | 
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| 570 | *  | 
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| 571 | * This method should only be used when a theme is currently active. However, it will fall over to the current  | 
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| 572 | * project directory.  | 
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| 573 | *  | 
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| 574 | * @param string $subtheme the subtheme path to get  | 
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| 575 | * @return string  | 
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| 576 | */  | 
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| 577 | 	public function ThemeDir($subtheme = false) { | 
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| 587 | |||
| 588 | /**  | 
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| 589 | * Get part of the current classes ancestry to be used as a CSS class.  | 
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| 590 | *  | 
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| 591 | * This method returns an escaped string of CSS classes representing the current classes ancestry until it hits a  | 
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| 592 | * stop point - e.g. "Page DataObject ViewableData".  | 
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| 593 | *  | 
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| 594 | * @param string $stopAtClass the class to stop at (default: ViewableData)  | 
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| 595 | * @return string  | 
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| 596 | * @uses ClassInfo  | 
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| 597 | */  | 
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| 598 | 	public function CSSClasses($stopAtClass = 'ViewableData') { | 
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| 615 | |||
| 616 | /**  | 
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| 617 | * Return debug information about this object that can be rendered into a template  | 
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| 618 | *  | 
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| 619 | * @return ViewableData_Debugger  | 
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| 620 | */  | 
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| 621 | 	public function Debug() { | 
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| 624 | |||
| 625 | }  | 
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| 626 | |||
| 782 | 
This check looks from parameters that have been defined for a function or method, but which are not used in the method body.