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: