Complex classes like StandardVariableProvider 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 StandardVariableProvider, and based on these observations, apply Extract Interface, too.
1 | <?php |
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13 | class StandardVariableProvider implements VariableProviderInterface |
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14 | { |
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15 | const ACCESSOR_ARRAY = 'array'; |
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16 | const ACCESSOR_GETTER = 'getter'; |
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17 | const ACCESSOR_ASSERTER = 'asserter'; |
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18 | const ACCESSOR_PUBLICPROPERTY = 'public'; |
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19 | |||
20 | /** |
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21 | * Variables stored in context |
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22 | * |
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23 | * @var mixed |
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24 | */ |
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25 | protected $variables = []; |
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26 | |||
27 | /** |
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28 | * Variables, if any, with which to initialize this |
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29 | * VariableProvider. |
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30 | * |
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31 | * @param array $variables |
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32 | */ |
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33 | public function __construct(array $variables = []) |
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34 | { |
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35 | $this->variables = $variables; |
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36 | } |
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37 | |||
38 | /** |
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39 | * @param array $variables |
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40 | * @return VariableProviderInterface |
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41 | */ |
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42 | public function getScopeCopy(array $variables): VariableProviderInterface |
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43 | { |
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44 | if (!isset($variables['settings']) && isset($this->variables['settings'])) { |
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45 | $variables['settings'] = $this->variables['settings']; |
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46 | } |
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47 | return new static($variables); |
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48 | } |
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49 | |||
50 | /** |
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51 | * Set the source data used by this VariableProvider. The |
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52 | * source can be any type, but the type must of course be |
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53 | * supported by the VariableProvider itself. |
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54 | * |
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55 | * @param mixed $source |
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56 | * @return void |
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57 | */ |
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58 | public function setSource($source): void |
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62 | |||
63 | /** |
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64 | * @return mixed |
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65 | */ |
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66 | public function getSource() |
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70 | |||
71 | /** |
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72 | * Get every variable provisioned by the VariableProvider |
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73 | * implementing the interface. Must return an array or |
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74 | * ArrayAccess instance! |
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75 | * |
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76 | * @return array |
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77 | */ |
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78 | public function getAll(): array |
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82 | |||
83 | /** |
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84 | * Add a variable to the context |
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85 | * |
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86 | * @param string $identifier Identifier of the variable to add |
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87 | * @param mixed $value The variable's value |
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88 | * @return void |
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89 | */ |
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90 | public function add(string $identifier, $value): void |
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94 | |||
95 | /** |
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96 | * Get a variable from the context. Throws exception if variable is not found in context. |
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97 | * |
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98 | * If "_all" is given as identifier, all variables are returned in an array, |
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99 | * if one of the other reserved variables are given, their appropriate value |
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100 | * they're representing is returned. |
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101 | * |
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102 | * @param string $identifier |
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103 | * @return mixed The variable value identified by $identifier |
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104 | */ |
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105 | public function get(string $identifier) |
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109 | |||
110 | /** |
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111 | * Get a variable by dotted path expression, retrieving the |
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112 | * variable from nested arrays/objects one segment at a time. |
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113 | * If the second variable is passed, it is expected to contain |
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114 | * extraction method names (constants from VariableExtractor) |
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115 | * which indicate how each value is extracted. |
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116 | * |
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117 | * @param string $path |
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118 | * @param array $accessors Optional list of accessors (see class constants) |
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119 | * @return mixed |
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120 | */ |
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121 | public function getByPath(string $path, array $accessors = []) |
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133 | |||
134 | /** |
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135 | * Remove a variable from context. Throws exception if variable is not found in context. |
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136 | * |
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137 | * @param string $identifier The identifier to remove |
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138 | * @return void |
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139 | */ |
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140 | public function remove(string $identifier): void |
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144 | |||
145 | /** |
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146 | * Returns an array of all identifiers available in the context. |
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147 | * |
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148 | * @return array Array of identifier strings |
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149 | */ |
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150 | public function getAllIdentifiers(): array |
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154 | |||
155 | /** |
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156 | * Checks if this property exists in the VariableContainer. |
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157 | * |
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158 | * @param string $identifier |
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159 | * @return boolean TRUE if $identifier exists, FALSE otherwise |
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160 | */ |
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161 | public function exists(string $identifier): bool |
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165 | |||
166 | /** |
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167 | * @param string $propertyPath |
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168 | * @return array |
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169 | */ |
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170 | public function getAccessorsForPath(string $propertyPath): array |
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189 | |||
190 | /** |
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191 | * Extracts a single value from an array or object. |
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192 | * |
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193 | * @param mixed $subject |
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194 | * @param string $propertyName |
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195 | * @param string|null $accessor |
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196 | * @return mixed |
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197 | */ |
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198 | protected function extractSingleValue($subject, string $propertyName, ?string $accessor = null) |
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205 | |||
206 | /** |
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207 | * Returns TRUE if the data type of $subject is potentially compatible |
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208 | * with the $accessor. |
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209 | * |
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210 | * @param mixed $subject |
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211 | * @param string $propertyName |
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212 | * @param string $accessor |
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213 | * @return boolean |
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214 | */ |
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215 | protected function canExtractWithAccessor($subject, string $propertyName, string $accessor): bool |
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229 | |||
230 | /** |
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231 | * @param mixed $subject |
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232 | * @param string $propertyName |
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233 | * @param string|null $accessor |
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234 | * @return mixed |
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235 | */ |
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236 | protected function extractWithAccessor($subject, string $propertyName, ?string $accessor) |
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253 | |||
254 | /** |
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255 | * Detect which type of accessor to use when extracting |
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256 | * $propertyName from $subject. |
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257 | * |
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258 | * @param mixed $subject |
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259 | * @param string $propertyName |
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260 | * @return string|null |
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261 | */ |
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262 | protected function detectAccessor($subject, string $propertyName): ?string |
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283 | |||
284 | /** |
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285 | * Tests whether a property can be extracted through `is*` or `has*` methods. |
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286 | * |
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287 | * @param mixed $subject |
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288 | * @param string $propertyName |
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289 | * @return bool |
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290 | */ |
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291 | protected function isExtractableThroughAsserter($subject, string $propertyName): bool |
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296 | |||
297 | /** |
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298 | * Extracts a property through `is*` or `has*` methods. |
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299 | * |
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300 | * @param object $subject |
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301 | * @param string $propertyName |
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302 | * @return mixed |
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303 | */ |
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304 | protected function extractThroughAsserter(object $subject, string $propertyName) |
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312 | } |
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313 |
In PHP, under loose comparison (like
==
, or!=
, orswitch
conditions), values of different types might be equal.For
string
values, the empty string''
is a special case, in particular the following results might be unexpected: