Complex classes like Cursor 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 Cursor, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 32 | class Cursor implements \Iterator, \Countable, \arrayaccess { |
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| 33 | |||
| 34 | /** |
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| 35 | * @var ResponseInterface |
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| 36 | */ |
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| 37 | protected $response; |
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| 38 | |||
| 39 | /** |
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| 40 | * @var AbstractObject[] |
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| 41 | */ |
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| 42 | protected $objects = array(); |
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| 43 | |||
| 44 | /** |
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| 45 | * @var int|null |
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| 46 | */ |
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| 47 | protected $indexLeft; |
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| 48 | |||
| 49 | /** |
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| 50 | * @var int|null |
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| 51 | */ |
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| 52 | protected $indexRight; |
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| 53 | |||
| 54 | /** |
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| 55 | * @var int|null |
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| 56 | */ |
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| 57 | protected $position; |
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| 58 | |||
| 59 | /** |
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| 60 | * @var AbstractObject |
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| 61 | */ |
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| 62 | protected $objectPrototype; |
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| 63 | |||
| 64 | /** |
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| 65 | * @var bool |
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| 66 | */ |
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| 67 | protected static $defaultUseImplicitFetch = false; |
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| 68 | |||
| 69 | /** |
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| 70 | * @var bool |
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| 71 | */ |
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| 72 | protected $useImplicitFectch; |
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| 73 | |||
| 74 | 24 | public function __construct( |
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| 75 | ResponseInterface $response, AbstractObject $object_prototype) { |
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| 76 | |||
| 77 | 24 | $this->response = $response; |
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| 78 | 24 | $this->objectPrototype = $object_prototype; |
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| 79 | 24 | $this->appendResponse($response); |
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| 80 | 18 | } |
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| 81 | |||
| 82 | /** |
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| 83 | * @param array $object_data |
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| 84 | * @return AbstractObject |
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| 85 | */ |
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| 86 | 16 | protected function createObject(array $object_data) { |
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| 87 | 16 | $object = clone $this->objectPrototype; |
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| 88 | 16 | $object->setDataWithoutValidation($object_data); |
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| 89 | |||
| 90 | 16 | return $object; |
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| 91 | } |
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| 92 | |||
| 93 | /** |
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| 94 | * @param ResponseInterface $response |
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| 95 | * @return array |
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| 96 | * @throws \InvalidArgumentException |
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| 97 | */ |
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| 98 | 24 | protected function assureResponseData(ResponseInterface $response) { |
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| 99 | 24 | $content = $response->getContent(); |
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| 100 | 24 | if (!isset($content['data']) || !is_array($content['data'])) { |
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| 101 | 6 | throw new \InvalidArgumentException("Malformed response data"); |
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| 102 | } |
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| 103 | |||
| 104 | 18 | return $content['data']; |
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| 105 | } |
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| 106 | |||
| 107 | /** |
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| 108 | * @param ResponseInterface $response |
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| 109 | */ |
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| 110 | 2 | protected function prependResponse(ResponseInterface $response) { |
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| 111 | 2 | $this->response = $response; |
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| 112 | 2 | $data = $this->assureResponseData($response); |
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| 113 | 2 | if (empty($data)) { |
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| 114 | 2 | return; |
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| 115 | } |
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| 116 | |||
| 117 | 2 | $left_index = $this->indexLeft; |
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| 118 | 2 | $count = count($data); |
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| 119 | 2 | $position = $count - 1; |
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| 120 | 2 | for ($i = $left_index - 1; $i >= $left_index - $count; $i--) { |
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| 121 | 2 | $this->objects[$i] = $this->createObject($data[$position--]); |
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| 122 | 2 | --$this->indexLeft; |
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| 123 | } |
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| 124 | 2 | } |
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| 125 | |||
| 126 | /** |
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| 127 | * @param ResponseInterface $response |
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| 128 | */ |
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| 129 | 24 | protected function appendResponse(ResponseInterface $response) { |
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| 130 | 24 | $this->response = $response; |
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| 131 | 24 | $data = $this->assureResponseData($response); |
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| 132 | 18 | if (empty($data)) { |
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| 133 | 10 | return; |
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| 134 | } |
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| 135 | |||
| 136 | 16 | if ($this->indexRight === null) { |
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| 137 | 16 | $this->indexLeft = 0; |
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| 138 | 16 | $this->indexRight = -1; |
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| 139 | 16 | $this->position = 0; |
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| 140 | } |
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| 141 | |||
| 142 | 16 | $this->indexRight += count($data); |
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| 143 | |||
| 144 | 16 | foreach ($data as $object_data) { |
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| 145 | 16 | $this->objects[] = $this->createObject($object_data); |
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| 146 | } |
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| 147 | 16 | } |
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| 148 | |||
| 149 | /** |
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| 150 | * @return bool |
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| 151 | */ |
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| 152 | 2 | public static function getDefaultUseImplicitFetch() { |
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| 153 | 2 | return static::$defaultUseImplicitFetch; |
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| 154 | } |
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| 155 | |||
| 156 | /** |
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| 157 | * @param bool $use_implicit_fectch |
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| 158 | */ |
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| 159 | 2 | public static function setDefaultUseImplicitFetch($use_implicit_fectch) { |
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| 160 | 2 | static::$defaultUseImplicitFetch = $use_implicit_fectch; |
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| 161 | 2 | } |
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| 162 | |||
| 163 | /** |
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| 164 | * @return bool |
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| 165 | */ |
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| 166 | 4 | public function getUseImplicitFetch() { |
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| 167 | 4 | return $this->useImplicitFectch !== null |
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| 168 | 2 | ? $this->useImplicitFectch |
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| 169 | 4 | : static::$defaultUseImplicitFetch; |
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| 170 | } |
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| 171 | |||
| 172 | /** |
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| 173 | * @param bool $use_implicit_fectch |
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| 174 | */ |
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| 175 | 2 | public function setUseImplicitFetch($use_implicit_fectch) { |
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| 176 | 2 | $this->useImplicitFectch = $use_implicit_fectch; |
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| 177 | 2 | } |
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| 178 | |||
| 179 | /** |
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| 180 | * @return string|null |
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| 181 | */ |
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| 182 | 7 | public function getBefore() { |
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| 183 | 7 | $content = $this->getLastResponse()->getContent(); |
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| 184 | |||
| 185 | 7 | return isset($content['paging']['cursors']['before']) |
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| 186 | 2 | ? $content['paging']['cursors']['before'] |
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| 187 | 7 | : null; |
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| 188 | } |
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| 189 | |||
| 190 | /** |
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| 191 | * @return string|null |
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| 192 | */ |
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| 193 | 8 | public function getAfter() { |
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| 194 | 8 | $content = $this->getLastResponse()->getContent(); |
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| 195 | |||
| 196 | 8 | return isset($content['paging']['cursors']['after']) |
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| 197 | 5 | ? $content['paging']['cursors']['after'] |
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| 198 | 8 | : null; |
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| 199 | } |
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| 200 | |||
| 201 | /** |
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| 202 | * @return RequestInterface |
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| 203 | */ |
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| 204 | 4 | protected function createUndirectionalizedRequest() { |
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| 205 | 4 | $request = $this->getLastResponse()->getRequest()->createClone(); |
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| 206 | 4 | $params = $request->getQueryParams(); |
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| 207 | 4 | if (array_key_exists('before', $params)) { |
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| 208 | 2 | unset($params['before']); |
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| 209 | } |
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| 210 | 4 | if (array_key_exists('after', $params)) { |
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| 211 | 2 | unset($params['after']); |
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| 212 | } |
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| 213 | |||
| 214 | 4 | return $request; |
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| 215 | } |
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| 216 | |||
| 217 | /** |
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| 218 | * @return string|null |
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| 219 | */ |
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| 220 | 6 | public function getPrevious() { |
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| 221 | 6 | $content = $this->getLastResponse()->getContent(); |
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| 222 | 6 | if (isset($content['paging']['previous'])) { |
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| 223 | 1 | return $content['paging']['previous']; |
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| 224 | } |
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| 225 | |||
| 226 | 5 | $before = $this->getBefore(); |
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| 227 | 5 | if ($before !== null) { |
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| 228 | 1 | $request = $this->createUndirectionalizedRequest(); |
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| 229 | 1 | $request->getQueryParams()->offsetSet('before', $before); |
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| 230 | 1 | return $request->getUrl(); |
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| 231 | } |
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| 232 | |||
| 233 | 4 | return null; |
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| 234 | } |
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| 235 | |||
| 236 | /** |
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| 237 | * @return string|null |
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| 238 | */ |
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| 239 | 10 | public function getNext() { |
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| 240 | 10 | $content = $this->getLastResponse()->getContent(); |
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| 241 | 10 | if (isset($content['paging']['next'])) { |
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| 242 | 4 | return $content['paging']['next']; |
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| 243 | } |
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| 244 | |||
| 245 | 6 | $after = $this->getAfter(); |
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| 246 | 6 | if ($after !== null) { |
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| 247 | 4 | $request = $this->createUndirectionalizedRequest(); |
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| 248 | 4 | $request->getQueryParams()->offsetSet('after', $after); |
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| 249 | 4 | return $request->getUrl(); |
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| 250 | } |
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| 251 | |||
| 252 | 2 | return null; |
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| 253 | } |
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| 254 | |||
| 255 | /** |
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| 256 | * @param string $url |
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| 257 | * @return RequestInterface |
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| 258 | */ |
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| 259 | 8 | protected function createRequestFromUrl($url) { |
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| 260 | 8 | $components = parse_url($url); |
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| 261 | 8 | $request = $this->getLastResponse()->getRequest()->createClone(); |
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| 262 | 8 | $request->setDomain($components['host']); |
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| 263 | 8 | $query = isset($components['query']) |
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| 264 | 8 | ? Util::parseUrlQuery($components['query']) |
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| 265 | 8 | : array(); |
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| 266 | 8 | $request->getQueryParams()->enhance($query); |
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| 267 | |||
| 268 | 8 | return $request; |
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| 269 | } |
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| 270 | |||
| 271 | /** |
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| 272 | * @return RequestInterface|null |
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| 273 | */ |
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| 274 | 6 | public function createBeforeRequest() { |
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| 275 | 6 | $url = $this->getPrevious(); |
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| 276 | 6 | return $url !== null ? $this->createRequestFromUrl($url) : null; |
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| 277 | } |
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| 278 | |||
| 279 | /** |
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| 280 | * @return RequestInterface|null |
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| 281 | */ |
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| 282 | 10 | public function createAfterRequest() { |
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| 283 | 10 | $url = $this->getNext(); |
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| 284 | 10 | return $url !== null ? $this->createRequestFromUrl($url) : null; |
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| 285 | } |
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| 286 | |||
| 287 | 6 | public function fetchBefore() { |
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| 288 | 6 | $request = $this->createBeforeRequest(); |
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| 289 | 6 | if (!$request) { |
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| 290 | 4 | return; |
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| 291 | } |
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| 292 | |||
| 293 | 2 | $this->prependResponse($request->execute()); |
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| 294 | 2 | } |
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| 295 | |||
| 296 | 10 | public function fetchAfter() { |
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| 297 | 10 | $request = $this->createAfterRequest(); |
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| 298 | 10 | if (!$request) { |
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| 299 | 2 | return; |
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| 300 | } |
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| 301 | |||
| 302 | 8 | $this->appendResponse($request->execute()); |
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| 303 | 8 | } |
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| 304 | |||
| 305 | /** |
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| 306 | * @deprecated Use getArrayCopy() |
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| 307 | * @return AbstractObject[] |
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| 308 | */ |
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| 309 | 2 | public function getObjects() { |
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| 310 | 2 | return $this->objects; |
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| 311 | } |
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| 312 | |||
| 313 | /** |
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| 314 | * @param bool $ksort |
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| 315 | * @return AbstractObject[] |
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| 316 | */ |
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| 317 | 2 | public function getArrayCopy($ksort = false) { |
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| 318 | 2 | if ($ksort) { |
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| 319 | // Sort the main array to improve best case performance in future |
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| 320 | // invocations |
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| 321 | 2 | ksort($this->objects); |
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| 322 | } |
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| 323 | |||
| 324 | 2 | return $this->objects; |
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| 325 | } |
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| 326 | |||
| 327 | /** |
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| 328 | * @deprecated Use getLastResponse() |
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| 329 | * @return ResponseInterface |
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| 330 | */ |
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| 331 | 2 | public function getResponse() { |
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| 332 | 2 | return $this->response; |
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| 333 | } |
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| 334 | |||
| 335 | /** |
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| 336 | * @return ResponseInterface |
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| 337 | */ |
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| 338 | 12 | public function getLastResponse() { |
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| 339 | 12 | return $this->response; |
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| 340 | } |
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| 341 | |||
| 342 | /** |
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| 343 | * @return int |
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| 344 | */ |
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| 345 | 8 | public function getIndexLeft() { |
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| 346 | 8 | return $this->indexLeft; |
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| 347 | } |
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| 348 | |||
| 349 | /** |
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| 350 | * @return int |
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| 351 | */ |
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| 352 | 6 | public function getIndexRight() { |
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| 353 | 6 | return $this->indexRight; |
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| 354 | } |
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| 355 | |||
| 356 | 4 | public function rewind() { |
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| 357 | 4 | $this->position = $this->indexLeft; |
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| 358 | 4 | } |
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| 359 | |||
| 360 | 2 | public function end() { |
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| 361 | 2 | $this->position = $this->indexRight; |
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| 362 | 2 | } |
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| 363 | |||
| 364 | /** |
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| 365 | * @param int $position |
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| 366 | */ |
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| 367 | 2 | public function seekTo($position) { |
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| 368 | 2 | $position = array_key_exists($position, $this->objects) ? $position : null; |
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| 369 | 2 | $this->position = $position; |
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| 370 | 2 | } |
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| 371 | |||
| 372 | /** |
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| 373 | * @return AbstractObject|bool |
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| 374 | */ |
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| 375 | 2 | public function current() { |
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| 376 | 2 | return isset($this->objects[$this->position]) |
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| 377 | 2 | ? $this->objects[$this->position] |
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| 378 | 2 | : false; |
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| 379 | } |
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| 380 | |||
| 381 | /** |
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| 382 | * @return int |
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| 383 | */ |
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| 384 | 4 | public function key() { |
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| 387 | |||
| 388 | 4 | public function prev() { |
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| 389 | 4 | if ($this->position == $this->getIndexLeft()) { |
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| 390 | 2 | if ($this->getUseImplicitFetch()) { |
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| 391 | 2 | $this->fetchBefore(); |
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| 392 | 2 | if ($this->position == $this->getIndexLeft()) { |
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| 393 | 2 | $this->position = null; |
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| 394 | } else { |
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| 395 | 2 | --$this->position; |
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| 396 | } |
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| 397 | } else { |
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| 398 | 2 | $this->position = null; |
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| 399 | } |
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| 400 | } else { |
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| 401 | 4 | --$this->position; |
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| 402 | } |
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| 403 | 4 | } |
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| 404 | |||
| 405 | 6 | public function next() { |
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| 406 | 6 | if ($this->position == $this->getIndexRight()) { |
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| 407 | 4 | if ($this->getUseImplicitFetch()) { |
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| 408 | 2 | $this->fetchAfter(); |
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| 409 | 2 | if ($this->position == $this->getIndexRight()) { |
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| 410 | 2 | $this->position = null; |
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| 411 | } else { |
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| 412 | 2 | ++$this->position; |
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| 413 | } |
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| 414 | } else { |
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| 415 | 4 | $this->position = null; |
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| 416 | } |
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| 417 | } else { |
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| 418 | 6 | ++$this->position; |
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| 419 | } |
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| 420 | 6 | } |
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| 421 | |||
| 422 | /** |
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| 423 | * @return bool |
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| 424 | */ |
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| 425 | 4 | public function valid() { |
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| 428 | |||
| 429 | /** |
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| 430 | * @return int |
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| 431 | */ |
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| 432 | 10 | public function count() { |
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| 435 | |||
| 436 | /** |
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| 437 | * @param mixed $offset |
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| 438 | * @param mixed $value |
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| 439 | */ |
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| 440 | 2 | public function offsetSet($offset, $value) { |
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| 441 | 2 | if ($offset === null) { |
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| 442 | 2 | $this->objects[] = $value; |
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| 443 | } else { |
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| 444 | 2 | $this->objects[$offset] = $value; |
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| 445 | } |
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| 446 | 2 | } |
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| 447 | |||
| 448 | /** |
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| 449 | * @param mixed $offset |
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| 450 | * @return bool |
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| 451 | */ |
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| 452 | 2 | public function offsetExists($offset) { |
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| 455 | |||
| 456 | /** |
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| 457 | * @param mixed $offset |
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| 458 | */ |
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| 459 | 2 | public function offsetUnset($offset) { |
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| 462 | |||
| 463 | /** |
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| 464 | * @param mixed $offset |
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| 465 | * @return mixed |
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| 466 | */ |
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| 467 | 2 | public function offsetGet($offset) { |
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| 470 | } |
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| 471 |
PHP Analyzer performs a side-effects analysis of your code. A side-effect is basically anything that might be visible after the scope of the method is left.
Let’s take a look at an example:
If we look at the
getEmail()method, we can see that it has no side-effect. Whether you call this method or not, no future calls to other methods are affected by this. As such code as the following is useless:On the hand, if we look at the
setEmail(), this method _has_ side-effects. In the following case, we could not remove the method call: