Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like Variables 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 Variables, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 28 | class Variables implements \ArrayAccess  | 
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| 29 | { | 
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| 30 | /**  | 
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| 31 | * @var array  | 
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| 32 | */  | 
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| 33 | private $variables = array();  | 
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| 34 | |||
| 35 | /**  | 
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| 36 | * @var Variables  | 
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| 37 | */  | 
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| 38 | private $parent;  | 
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| 39 | |||
| 40 | /**  | 
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| 41 | * @var Variables[]  | 
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| 42 | */  | 
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| 43 | private $children = array();  | 
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| 44 | |||
| 45 | /**  | 
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| 46 | * Variables constructor.  | 
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| 47 | *  | 
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| 48 | * @param Variables|null $parent Parent variables container  | 
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| 49 | * @param array $defaults Array with default values  | 
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| 50 | */  | 
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| 51 | public function __construct(Variables $parent = null, array $defaults = array())  | 
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| 72 | |||
| 73 | /**  | 
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| 74 | * Clone the children with this step as well, cause otherwise they'll lose  | 
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| 75 | * connection to parent  | 
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| 76 | *  | 
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| 77 | * @return void  | 
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| 78 | */  | 
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| 79 | function __clone()  | 
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| 88 | |||
| 89 | /**  | 
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| 90 | * Bind to another parent  | 
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| 91 | *  | 
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| 92 | * @param Variables $newParent The new parent  | 
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| 93 | *  | 
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| 94 | * @return void  | 
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| 95 | */  | 
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| 96 | public function bindTo(Variables $newParent)  | 
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| 109 | |||
| 110 | /**  | 
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| 111 | * Get the parent variables object, if any  | 
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| 112 | *  | 
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| 113 | * @return Variables  | 
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| 114 | */  | 
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| 115 | public function getParent()  | 
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| 119 | |||
| 120 | /**  | 
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| 121 | * Provide an array of variable configurations:  | 
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| 122 | * - Keys are the variable names  | 
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| 123 | * - Values can be  | 
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| 124 | * -- an array with the configuration - following keys are interpreted:  | 
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| 125 | * --- required (defaults to false)  | 
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| 126 | * --- default (defaults to null, ignored when required)  | 
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| 127 | * -- null: The default value will be set to null  | 
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| 128 | * -- false: No default value will be set  | 
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| 129 | *  | 
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| 130 | * Also you can add a "--" with numeric key, to state the boundaries of  | 
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| 131 | * current and parent variables configuration  | 
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| 132 | *  | 
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| 133 | * In either case variables in this configuration will always be fetched  | 
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| 134 | * from and saved to the very scope of this variables object (this)  | 
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| 135 | *  | 
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| 136 | * @return array  | 
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| 137 | */  | 
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| 138 | protected function configureVariables()  | 
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| 142 | |||
| 143 | /**  | 
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| 144 | * Get a variable from this very object (unexpanded)  | 
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| 145 | *  | 
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| 146 | * @param mixed $offset Variable name  | 
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| 147 | *  | 
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| 148 | * @internal Required set/get/has/remove in order to access entries of Variables  | 
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| 149 | * without looking up parents.  | 
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| 150 | * You can however override this to do your own logic on plain offsets  | 
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| 151 | * (no dot paths as in set/get/has/remove).  | 
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| 152 | *  | 
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| 153 | * @return mixed  | 
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| 154 | */  | 
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| 155 | public function &offsetGet($offset)  | 
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| 159 | |||
| 160 | /**  | 
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| 161 | * Determine if a variable is available on this very object  | 
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| 162 | *  | 
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| 163 | * @param mixed $offset Variable name  | 
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| 164 | *  | 
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| 165 |      * @internal See {@see Variables::offsetGet()} | 
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| 166 | *  | 
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| 167 | * @return boolean  | 
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| 168 | */  | 
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| 169 | public function offsetExists($offset)  | 
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| 173 | |||
| 174 | /**  | 
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| 175 | * Set a variable on this very object  | 
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| 176 | *  | 
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| 177 | * @param mixed $offset Variable name  | 
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| 178 | * @param mixed $value The value  | 
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| 179 | *  | 
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| 180 |      * @internal See {@see Variables::offsetGet()} | 
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| 181 | *  | 
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| 182 | * @return void  | 
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| 183 | */  | 
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| 184 | public function offsetSet($offset, $value)  | 
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| 188 | |||
| 189 | /**  | 
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| 190 | * Unset a variable from this very object  | 
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| 191 | *  | 
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| 192 | * @param mixed $offset Variable name  | 
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| 193 | *  | 
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| 194 |      * @internal See {@see Variables::offsetGet()} | 
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| 195 | *  | 
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| 196 | * @return mixed  | 
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| 197 | */  | 
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| 198 | public function offsetUnset($offset)  | 
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| 202 | |||
| 203 | |||
| 204 | /**  | 
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| 205 | * Find the first context that contains the first part of the variable  | 
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| 206 | * (this will always return current context - configured variables as well)  | 
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| 207 | *  | 
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| 208 | * @param array $variableParts The path split by dot  | 
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| 209 | *  | 
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| 210 | * @return Variables  | 
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| 211 | */  | 
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| 212 | private function findContext(&$variableParts)  | 
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| 240 | |||
| 241 | /**  | 
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| 242 | * Get an expanded variable by it's path (second argument can be a default value)  | 
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| 243 | *  | 
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| 244 | * @param string $name The variable name  | 
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| 245 | *  | 
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| 246 | * @final This method is not to be overwritten as logic is to complex to deal  | 
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| 247 | * with overrides because callee detection might be introduced later on  | 
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| 248 | * and the expansion logic of dot path's is mostly internal.  | 
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| 249 | * If you need to intercept the variable handling rather override  | 
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| 250 | * offsetSet, offsetGet, offsetExists or offsetUnset.  | 
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| 251 | *  | 
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| 252 | * @return mixed  | 
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| 253 | */  | 
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| 254 | final public function get($name)  | 
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| 285 | |||
| 286 | /**  | 
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| 287 | * Determine if a variable path is available  | 
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| 288 | *  | 
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| 289 | * @param string $name The variable name  | 
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| 290 | *  | 
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| 291 |      * @final See {@see Variables::get()} | 
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| 292 | *  | 
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| 293 | * @return boolean  | 
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| 294 | */  | 
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| 295 | final public function has($name)  | 
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| 315 | |||
| 316 | /**  | 
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| 317 | * Set a variable by it's path  | 
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| 318 | *  | 
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| 319 | * @param string $name The variable name  | 
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| 320 | * @param mixed $value The value  | 
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| 321 | *  | 
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| 322 |      * @final See {@see Variables::get()} | 
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| 323 | *  | 
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| 324 | * @return $this  | 
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| 325 | */  | 
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| 326 | final public function set($name, $value)  | 
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| 363 | |||
| 364 | /**  | 
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| 365 | * Unset a variable by it's path  | 
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| 366 | *  | 
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| 367 | * @param string $name Variable name  | 
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| 368 | *  | 
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| 369 |      * @final See {@see Variables::get()} | 
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| 370 | *  | 
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| 371 | * @return $this  | 
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| 372 | */  | 
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| 373 | final public function remove($name)  | 
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| 407 | |||
| 408 | /**  | 
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| 409 | * Determine if a variable is an array or accessible as array and has the key  | 
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| 410 | *  | 
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| 411 | * This method is required as isset returns false on existing keys with null  | 
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| 412 |      * values and array_key_exists doesn't invoke {@see \ArrayAccess::offsetExists()} | 
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| 413 | *  | 
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| 414 |      * Use this BEFORE {@see Variables::propertyExists()} in according checks, as | 
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| 415 |      * it will match {@see Variables} objects as well. This will likely speed things | 
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| 416 | * up a little but more importantly it will avoid that private or protected  | 
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| 417 |      * properties are detected by {@see Variables::propertyExists()}. | 
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| 418 | *  | 
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| 419 | * @param array|\ArrayAccess $array Array  | 
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| 420 | * @param string $key The key  | 
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| 421 | *  | 
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| 422 | * @return bool  | 
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| 423 | */  | 
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| 424 | private function arrayKeyExists($array, $key)  | 
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| 433 | |||
| 434 | /**  | 
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| 435 | * Determine if a variable is an object and has a property  | 
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| 436 | *  | 
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| 437 | * This method is required as isset returns false on existing properties with  | 
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| 438 |      * null values and property_exists doesn't invoke {@see __isset()} | 
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| 439 | *  | 
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| 440 | * @param object $object The object  | 
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| 441 | * @param string $property The property  | 
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| 442 | *  | 
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| 443 | * @return bool  | 
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| 444 | */  | 
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| 445 | private function propertyExists($object, $property)  | 
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| 457 | |||
| 458 | /**  | 
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| 459 | * Set from array  | 
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| 460 | *  | 
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| 461 | * @param array $values Array with key value pairs  | 
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| 462 | *  | 
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| 463 | * @return $this  | 
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| 464 | */  | 
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| 465 | public function setFromArray($values)  | 
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| 472 | |||
| 473 | /**  | 
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| 474 | * Expand expressions within the $value  | 
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| 475 | *  | 
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| 476 | * @param mixed $value The value  | 
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| 477 | *  | 
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| 478 | * @return string|mixed  | 
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| 479 | */  | 
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| 480 | public function expand($value)  | 
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| 488 | |||
| 489 | /**  | 
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| 490 | * Handles special variable names  | 
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| 491 | *  | 
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| 492 | * @param string $key Current part of the complete variable name  | 
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| 493 | * @param mixed $value The value  | 
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| 494 | *  | 
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| 495 | * @return void  | 
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| 496 | */  | 
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| 497 | private function filterSpecialNames(&$key, &$value)  | 
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| 518 | }  | 
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| 519 | ?>  | 
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| 520 | 
Adding explicit visibility (
private,protected, orpublic) is generally recommend to communicate to other developers how, and from where this method is intended to be used.