Complex classes like Session 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 Session, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 9 | class Session implements \ArrayAccess  | 
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| 10 | { | 
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| 11 | use EmitterAwareTrait;  | 
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| 12 | |||
| 13 | const DEFAULT_NAMESPACE = 'default';  | 
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| 14 | const METADATA_NAMESPACE = '__metadata__';  | 
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| 15 | |||
| 16 | /** @var Id\Handler */  | 
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| 17 | private $idHandler;  | 
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| 18 | |||
| 19 | /** @var int Number of requests after which id is regeneratd */  | 
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| 20 | private $idRequestsLimit = null;  | 
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| 21 | |||
| 22 | /** @var int Time after id is regenerated */  | 
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| 23 | private $idTtl = 1440;  | 
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| 24 | |||
| 25 | /** @var bool */  | 
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| 26 | private $idRegenerated;  | 
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| 27 | |||
| 28 | /** @var int */  | 
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| 29 | private $regenerationTrace;  | 
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| 30 | |||
| 31 | /** @var StoreInterface */  | 
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| 32 | private $store;  | 
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| 33 | |||
| 34 | /** @var bool|mixed Session values */  | 
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| 35 | private $values = array();  | 
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| 36 | |||
| 37 | /** @var int Specifies the number of seconds after which session will be automatically expired */  | 
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| 38 | private $ttl = 1440;  | 
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| 39 | |||
| 40 | /** @var int First trace (timestamp), time when session was created */  | 
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| 41 | private $firstTrace;  | 
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| 42 | |||
| 43 | /** @var int Last trace (Unix timestamp) */  | 
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| 44 | private $lastTrace;  | 
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| 45 | |||
| 46 | /** @var int */  | 
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| 47 | private $requestsCount;  | 
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| 48 | |||
| 49 | /** @var FingerprintGeneratorInterface[] */  | 
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| 50 | private $fingerprintGenerators = array();  | 
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| 51 | |||
| 52 | /** @var string */  | 
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| 53 | private $fingerprint = '';  | 
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| 54 | |||
| 55 | /** @var bool Is session opened? */  | 
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| 56 | private $opened = false;  | 
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| 57 | |||
| 58 | /** @var SessionFlash */  | 
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| 59 | private $flash;  | 
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| 60 | |||
| 61 | /**  | 
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| 62 | * @param StoreInterface $store  | 
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| 63 | */  | 
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| 64 | public function __construct(StoreInterface $store)  | 
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| 71 | |||
| 72 | /**  | 
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| 73 | * Creates new session  | 
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| 74 | *  | 
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| 75 | * It should be called only once at the beginning. If called for existing  | 
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| 76 | * session it ovewrites it (clears all values etc).  | 
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| 77 |      * It can be replaced with {@link self::open()} (called with "true" argument) | 
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| 78 | *  | 
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| 79 | * @return bool Session opened?  | 
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| 80 | */  | 
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| 81 | public function create()  | 
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| 99 | |||
| 100 | /**  | 
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| 101 | * Opens the session (for a given request)  | 
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| 102 | *  | 
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| 103 |      * If session hasn't been created earlier with {@link self::create()} method then: | 
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| 104 | * - if argument is set to true, session will be created implicitly (behaves  | 
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| 105 | * like PHP's native session_start()),  | 
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| 106 | * - otherwise, session won't be created and apprporiate listeners will be notified.  | 
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| 107 | *  | 
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| 108 | * If called earlier, then second (and next ones) call does nothing  | 
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| 109 | *  | 
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| 110 | * @param bool $createNewIfNotExists Create new session if not exists earlier?  | 
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| 111 | * @return bool Session opened?  | 
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| 112 | */  | 
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| 113 | public function open($createNewIfNotExists = false)  | 
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| 136 | |||
| 137 | /**  | 
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| 138 | * Is session opened?  | 
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| 139 | *  | 
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| 140 | * @return bool  | 
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| 141 | */  | 
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| 142 | public function isOpened()  | 
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| 146 | |||
| 147 | /**  | 
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| 148 |      * Alias of {@link self::isOpened()}. | 
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| 149 | *  | 
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| 150 | * @return bool  | 
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| 151 | */  | 
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| 152 | public function isOpen()  | 
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| 156 | |||
| 157 | /**  | 
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| 158 | * Is session expired?  | 
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| 159 | *  | 
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| 160 | * @return bool  | 
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| 161 | */  | 
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| 162 | public function isExpired()  | 
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| 166 | |||
| 167 | /**  | 
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| 168 | * Close the session.  | 
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| 169 | */  | 
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| 170 | public function close()  | 
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| 184 | |||
| 185 | /**  | 
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| 186 | * Destroy the session.  | 
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| 187 | */  | 
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| 188 | public function destroy()  | 
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| 194 | |||
| 195 | /**  | 
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| 196 | * Get session identifier  | 
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| 197 | *  | 
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| 198 | * @return string  | 
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| 199 | */  | 
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| 200 | public function getId()  | 
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| 204 | |||
| 205 | /**  | 
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| 206 | * Regenerates session id.  | 
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| 207 | *  | 
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| 208 | * Destroys current session in store and generates new id, which will be saved  | 
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| 209 | * at the end of script execution (together with values).  | 
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| 210 | *  | 
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| 211 | * Id is regenerated at the most once per script execution (even if called a few times).  | 
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| 212 | *  | 
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| 213 | * Mitigates Session Fixation - use it whenever the user's privilege level changes.  | 
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| 214 | */  | 
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| 215 | public function regenerateId()  | 
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| 229 | |||
| 230 | /**  | 
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| 231 | * @param Id\Handler $idHandler  | 
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| 232 | */  | 
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| 233 | public function setIdHandler(Id\Handler $idHandler)  | 
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| 237 | |||
| 238 | /**  | 
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| 239 | * @return Id\Handler  | 
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| 240 | */  | 
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| 241 | public function getIdHandler()  | 
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| 249 | |||
| 250 | /**  | 
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| 251 | * @param int $limit  | 
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| 252 | */  | 
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| 253 | public function setIdRequestsLimit($limit)  | 
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| 257 | |||
| 258 | /**  | 
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| 259 | * @param int $ttl  | 
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| 260 | */  | 
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| 261 | public function setIdTtl($ttl)  | 
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| 265 | |||
| 266 | /**  | 
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| 267 | * Determine if session id should be regenerated? (based on request_counter or regenerationTrace)  | 
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| 268 | */  | 
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| 269 | protected function shouldRegenerateId()  | 
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| 281 | |||
| 282 | /**  | 
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| 283 | * @return StoreInterface  | 
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| 284 | */  | 
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| 285 | protected function getStore()  | 
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| 289 | |||
| 290 | /**  | 
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| 291 | * @param FingerprintGeneratorInterface $fingerprintGenerator  | 
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| 292 | */  | 
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| 293 | public function addFingerprintGenerator(FingerprintGeneratorInterface $fingerprintGenerator)  | 
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| 297 | |||
| 298 | /**  | 
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| 299 | * @return string  | 
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| 300 | */  | 
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| 301 | protected function generateFingerprint()  | 
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| 311 | |||
| 312 | /**  | 
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| 313 | * @return string  | 
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| 314 | */  | 
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| 315 | public function getFingerprint()  | 
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| 319 | |||
| 320 | /**  | 
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| 321 | * Gets first trace timestamp.  | 
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| 322 | *  | 
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| 323 | * @return int  | 
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| 324 | */  | 
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| 325 | public function getFirstTrace()  | 
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| 329 | |||
| 330 | /**  | 
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| 331 | * Updates last trace timestamp.  | 
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| 332 | */  | 
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| 333 | protected function updateLastTrace()  | 
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| 337 | |||
| 338 | /**  | 
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| 339 | * Gets last trace timestamp.  | 
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| 340 | *  | 
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| 341 | * @return int  | 
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| 342 | */  | 
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| 343 | public function getLastTrace()  | 
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| 347 | |||
| 348 | /**  | 
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| 349 | * Gets last (id) regeneration timestamp.  | 
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| 350 | *  | 
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| 351 | * @return int  | 
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| 352 | */  | 
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| 353 | public function getRegenerationTrace()  | 
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| 357 | |||
| 358 | /**  | 
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| 359 |      * It must be called before {@link self::open()}. | 
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| 360 | *  | 
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| 361 | * @param int $ttl  | 
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| 362 | * @throws Exception  | 
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| 363 | */  | 
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| 364 | public function setTtl($ttl)  | 
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| 376 | |||
| 377 | /**  | 
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| 378 | * @return int  | 
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| 379 | */  | 
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| 380 | public function getTtl()  | 
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| 384 | |||
| 385 | /**  | 
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| 386 | * @return int  | 
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| 387 | */  | 
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| 388 | public function getRequestsCount()  | 
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| 392 | |||
| 393 | /**  | 
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| 394 | * Sets session value in given or default namespace  | 
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| 395 | *  | 
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| 396 | * @param string $name  | 
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| 397 | * @param mixed $value  | 
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| 398 | * @param string $namespace  | 
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| 399 | */  | 
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| 400 | public function setValue($name, $value, $namespace = self::DEFAULT_NAMESPACE)  | 
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| 404 | |||
| 405 | /**  | 
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| 406 | * Gets session value from given or default namespace  | 
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| 407 | *  | 
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| 408 | * @param string $name  | 
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| 409 | * @param string $namespace  | 
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| 410 | * @return mixed  | 
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| 411 | */  | 
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| 412 | public function getValue($name, $namespace = self::DEFAULT_NAMESPACE)  | 
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| 416 | |||
| 417 | /**  | 
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| 418 | * Gets and unsets value (flash value) for given or default namespace  | 
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| 419 | *  | 
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| 420 | * @param string $name  | 
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| 421 | * @param string $namespace  | 
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| 422 | * @return mixed  | 
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| 423 | */  | 
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| 424 | public function getUnsetValue($name, $namespace = self::DEFAULT_NAMESPACE)  | 
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| 431 | |||
| 432 | /**  | 
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| 433 | * Get all values for given or default namespace  | 
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| 434 | *  | 
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| 435 | * @param string $namespace  | 
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| 436 | * @return array  | 
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| 437 | */  | 
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| 438 | public function getValues($namespace = self::DEFAULT_NAMESPACE)  | 
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| 442 | |||
| 443 | /**  | 
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| 444 | * @param string $name  | 
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| 445 | * @param string $namespace  | 
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| 446 | * @return bool  | 
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| 447 | */  | 
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| 448 | public function issetValue($name, $namespace = self::DEFAULT_NAMESPACE)  | 
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| 452 | |||
| 453 | /**  | 
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| 454 | * @param string $name  | 
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| 455 | * @param string $namespace  | 
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| 456 | */  | 
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| 457 | public function unsetValue($name, $namespace = self::DEFAULT_NAMESPACE)  | 
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| 463 | |||
| 464 | /**  | 
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| 465 | * @param string $namespace  | 
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| 466 | */  | 
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| 467 | public function unsetValues($namespace = self::DEFAULT_NAMESPACE)  | 
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| 473 | |||
| 474 | /**  | 
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| 475 | * @param mixed $offset  | 
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| 476 | * @param mixed $value  | 
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| 477 | */  | 
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| 478 | public function offsetSet($offset, $value)  | 
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| 482 | |||
| 483 | /**  | 
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| 484 | * @param mixed $offset  | 
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| 485 | * @return mixed  | 
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| 486 | */  | 
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| 487 | public function offsetGet($offset)  | 
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| 491 | |||
| 492 | /**  | 
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| 493 | * @param mixed $offset  | 
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| 494 | * @return bool  | 
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| 495 | */  | 
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| 496 | public function offsetExists($offset)  | 
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| 500 | |||
| 501 | /**  | 
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| 502 | * @param mixed $offset  | 
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| 503 | */  | 
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| 504 | public function offsetUnset($offset)  | 
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| 508 | |||
| 509 | /**  | 
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| 510 | * Loads session data from defined store.  | 
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| 511 | *  | 
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| 512 | * @return bool  | 
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| 513 | */  | 
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| 514 | protected function load()  | 
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| 536 | |||
| 537 | /**  | 
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| 538 | * Saves session data into defined store.  | 
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| 539 | *  | 
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| 540 | * @return bool  | 
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| 541 | */  | 
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| 542 | protected function save()  | 
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| 558 | |||
| 559 | /**  | 
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| 560 | * Put a key / value pair or array of key / value pairs in the session.  | 
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| 561 | *  | 
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| 562 | * @param string|array $key  | 
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| 563 | * @param mixed $value  | 
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| 564 | * @return void  | 
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| 565 | */  | 
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| 566 | public function put($key, $value = null)  | 
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| 576 | |||
| 577 | |||
| 578 | /**  | 
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| 579 | * Push a value onto a session array.  | 
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| 580 | *  | 
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| 581 | * @param string $key  | 
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| 582 | * @param mixed $value  | 
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| 583 | * @return void  | 
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| 584 | */  | 
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| 585 | public function push($key, $value)  | 
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| 591 | |||
| 592 | /**  | 
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| 593 | * Remove one or many items from the session.  | 
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| 594 | *  | 
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| 595 | * @param string|array $keys  | 
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| 596 | * @return void  | 
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| 597 | */  | 
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| 598 | public function forget($keys)  | 
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| 607 | |||
| 608 | |||
| 609 | /**  | 
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| 610 | * Call the flash session handler.  | 
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| 611 | *  | 
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| 612 | * @return SessionFlash  | 
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| 613 | */  | 
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| 614 | public function flash()  | 
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| 622 | }  | 
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| 623 | 
There are different options of fixing this problem.
If you want to be on the safe side, you can add an additional type-check:
If you are sure that the expression is traversable, you might want to add a doc comment cast to improve IDE auto-completion and static analysis:
Mark the issue as a false-positive: Just hover the remove button, in the top-right corner of this issue for more options.