Complex classes like BaseJWKSet 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 BaseJWKSet, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 19 | trait BaseJWKSet  | 
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| 20 | { | 
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| 21 | /**  | 
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| 22 | * @var int  | 
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| 23 | */  | 
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| 24 | private $position = 0;  | 
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| 25 | |||
| 26 | /**  | 
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| 27 | * @param int $index  | 
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| 28 | *  | 
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| 29 | * @return bool  | 
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| 30 | */  | 
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| 31 | public function hasKey($index)  | 
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| 35 | |||
| 36 | /**  | 
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| 37 | * @param int $index  | 
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| 38 | *  | 
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| 39 | * @return \Jose\Object\JWKInterface  | 
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| 40 | */  | 
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| 41 | public function getKey($index)  | 
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| 49 | |||
| 50 | /**  | 
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| 51 | * @return \Jose\Object\JWKInterface[]  | 
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| 52 | */  | 
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| 53 | abstract public function getKeys();  | 
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| 54 | |||
| 55 | /**  | 
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| 56 | * @param \Jose\Object\JWKInterface $key  | 
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| 57 | */  | 
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| 58 | abstract public function addKey(JWKInterface $key);  | 
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| 59 | |||
| 60 | /**  | 
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| 61 | * @param int $index  | 
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| 62 | */  | 
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| 63 | abstract public function removeKey($index);  | 
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| 64 | |||
| 65 | /**  | 
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| 66 | * @return array  | 
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| 67 | */  | 
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| 68 | public function jsonSerialize()  | 
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| 72 | |||
| 73 | /**  | 
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| 74 | * @param int $mode  | 
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| 75 | *  | 
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| 76 | * @return int  | 
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| 77 | */  | 
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| 78 | public function count($mode = COUNT_NORMAL)  | 
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| 82 | |||
| 83 | /**  | 
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| 84 | * @return \Jose\Object\JWKInterface|null  | 
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| 85 | */  | 
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| 86 | public function current()  | 
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| 90 | |||
| 91 | /**  | 
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| 92 | * @return int  | 
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| 93 | */  | 
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| 94 | public function key()  | 
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| 98 | |||
| 99 | public function next()  | 
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| 103 | |||
| 104 | public function rewind()  | 
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| 108 | |||
| 109 | /**  | 
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| 110 | * @return bool  | 
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| 111 | */  | 
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| 112 | public function valid()  | 
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| 116 | |||
| 117 | /**  | 
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| 118 | * @return int  | 
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| 119 | */  | 
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| 120 | public function countKeys()  | 
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| 124 | |||
| 125 | /**  | 
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| 126 | * @param mixed $offset  | 
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| 127 | *  | 
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| 128 | * @return bool  | 
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| 129 | */  | 
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| 130 | public function offsetExists($offset)  | 
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| 134 | |||
| 135 | /**  | 
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| 136 | * @param mixed $offset  | 
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| 137 | *  | 
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| 138 | * @return \Jose\Object\JWKInterface  | 
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| 139 | */  | 
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| 140 | public function offsetGet($offset)  | 
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| 144 | |||
| 145 | /**  | 
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| 146 | * @param mixed $offset  | 
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| 147 | * @param mixed $value  | 
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| 148 | */  | 
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| 149 | public function offsetSet($offset, $value)  | 
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| 153 | |||
| 154 | /**  | 
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| 155 | * @param int $offset  | 
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| 156 | */  | 
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| 157 | public function offsetUnset($offset)  | 
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| 161 | |||
| 162 | /**  | 
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| 163 | * @param string $type  | 
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| 164 | * @param null|string $algorithm  | 
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| 165 | * @param array $restrictions  | 
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| 166 | *  | 
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| 167 | * @return null|\Jose\Object\JWKInterface  | 
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| 168 | */  | 
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| 169 | public function selectKey($type, $algorithm = null, array $restrictions = [])  | 
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| 211 | |||
| 212 | /**  | 
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| 213 | * @param string $type  | 
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| 214 | * @param \Jose\Object\JWKInterface $key  | 
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| 215 | *  | 
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| 216 | * @return bool|int  | 
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| 217 | */  | 
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| 218 | private function canKeyBeUsedFor($type, JWKInterface $key)  | 
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| 229 | |||
| 230 | /**  | 
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| 231 | * @param null|string $algorithm  | 
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| 232 | * @param \Jose\Object\JWKInterface $key  | 
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| 233 | *  | 
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| 234 | * @return bool|int  | 
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| 235 | */  | 
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| 236 | private function canKeyBeUsedWithAlgorithm($algorithm, JWKInterface $key)  | 
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| 247 | |||
| 248 | /**  | 
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| 249 | * @param array $restrictions  | 
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| 250 | * @param \Jose\Object\JWKInterface $key  | 
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| 251 | *  | 
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| 252 | * @return bool  | 
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| 253 | */  | 
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| 254 | private function doesKeySatisfyRestrictions(array $restrictions, JWKInterface $key)  | 
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| 264 | |||
| 265 | /**  | 
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| 266 | * @param string $key_ops  | 
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| 267 | *  | 
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| 268 | * @return string  | 
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| 269 | */  | 
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| 270 | private static function convertKeyOpsToKeyUse($key_ops)  | 
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| 285 | |||
| 286 | /**  | 
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| 287 | * @param array $a  | 
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| 288 | * @param array $b  | 
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| 289 | *  | 
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| 290 | * @return int  | 
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| 291 | */  | 
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| 292 | public function sortKeys($a, $b)  | 
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| 300 | }  | 
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| 301 | 
This check looks from parameters that have been defined for a function or method, but which are not used in the method body.