Complex classes like ByPropertyIdArray 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 ByPropertyIdArray, and based on these observations, apply Extract Interface, too.
1 | <?php |
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46 | class ByPropertyIdArray extends ArrayObject { |
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47 | |||
48 | /** |
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49 | * @var array[]|null |
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50 | */ |
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51 | private $byId = null; |
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52 | |||
53 | /** |
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54 | * @see ArrayObject::__construct |
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55 | * |
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56 | 65 | * @param PropertyIdProvider[]|Traversable|null $input |
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57 | 65 | */ |
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58 | 65 | public function __construct( $input = null ) { |
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61 | |||
62 | /** |
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63 | * Builds the index for doing look-ups by property id. |
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64 | * |
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65 | 62 | * @since 0.2 |
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66 | 62 | */ |
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67 | public function buildIndex() { |
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81 | |||
82 | /** |
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83 | * Checks whether id indexed array has been generated. |
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84 | 64 | * |
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85 | 64 | * @throws RuntimeException |
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86 | 2 | */ |
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87 | private function assertIndexIsBuild() { |
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92 | |||
93 | /** |
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94 | * Returns the property ids used for indexing. |
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95 | * |
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96 | * @since 0.2 |
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97 | * |
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98 | 38 | * @return PropertyId[] |
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99 | 38 | * @throws RuntimeException |
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100 | */ |
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101 | 37 | public function getPropertyIds() { |
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111 | |||
112 | /** |
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113 | * Returns the objects featuring the provided property id in the index. |
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114 | * |
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115 | * @since 0.2 |
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116 | * |
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117 | * @param PropertyId $propertyId |
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118 | * |
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119 | * @throws OutOfBoundsException |
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120 | 27 | * @throws RuntimeException |
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121 | 27 | * @return PropertyIdProvider[] |
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122 | */ |
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123 | 26 | public function getByPropertyId( PropertyId $propertyId ) { |
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132 | |||
133 | /** |
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134 | * Returns the absolute index of an object or false if the object could not be found. |
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135 | * @since 0.5 |
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136 | * |
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137 | * @param PropertyIdProvider $object |
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138 | * |
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139 | 47 | * @return bool|int |
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140 | 47 | * @throws RuntimeException |
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141 | */ |
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142 | 47 | public function getFlatArrayIndexOfObject( $object ) { |
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154 | |||
155 | /** |
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156 | * Returns the objects in a flat array (using the indexed form for generating the array). |
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157 | * @since 0.5 |
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158 | * |
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159 | * @return PropertyIdProvider[] |
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160 | 55 | * @throws RuntimeException |
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161 | 55 | */ |
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162 | public function toFlatArray() { |
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171 | |||
172 | /** |
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173 | * Returns the absolute numeric indices of objects featuring the same property id. |
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174 | * |
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175 | * @param PropertyId $propertyId |
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176 | * |
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177 | * @throws RuntimeException |
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178 | 43 | * @return int[] |
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179 | 43 | */ |
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180 | private function getFlatArrayIndices( PropertyId $propertyId ) { |
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197 | |||
198 | /** |
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199 | * Moves an object within its "property group". |
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200 | * |
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201 | * @param PropertyIdProvider $object |
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202 | * @param int $toIndex Absolute index within a "property group". |
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203 | * |
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204 | 38 | * @throws OutOfBoundsException |
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205 | 38 | */ |
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206 | private function moveObjectInPropertyGroup( $object, $toIndex ) { |
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236 | |||
237 | /** |
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238 | * Moves an object to the end of its "property group". |
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239 | * |
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240 | 12 | * @param PropertyIdProvider $object |
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241 | 12 | */ |
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242 | private function moveObjectToEndOfPropertyGroup( $object ) { |
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257 | |||
258 | /** |
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259 | * Removes an object from the array structures. |
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260 | * |
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261 | * @param PropertyIdProvider $object |
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262 | 23 | */ |
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263 | 23 | private function removeObject( $object ) { |
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269 | |||
270 | /** |
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271 | * Inserts an object at a specific index. |
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272 | * |
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273 | * @param PropertyIdProvider $object |
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274 | * @param int $index Absolute index within the flat list of objects. |
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275 | 9 | */ |
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276 | 9 | private function insertObjectAtIndex( $object, $index ) { |
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287 | |||
288 | /** |
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289 | * @param PropertyId $propertyId |
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290 | * @param int $toIndex |
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291 | 32 | */ |
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292 | 32 | private function movePropertyGroup( PropertyId $propertyId, $toIndex ) { |
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339 | |||
340 | /** |
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341 | * Returns the index of a "property group" (the first object in the flat array that features |
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342 | * the specified property). Returns false if property id could not be found. |
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343 | * |
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344 | * @param PropertyId $propertyId |
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345 | * |
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346 | * @return bool|int |
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347 | 32 | */ |
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348 | 32 | private function getPropertyGroupIndex( PropertyId $propertyId ) { |
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361 | |||
362 | /** |
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363 | * Moves an existing object to a new index. Specifying an index outside the object's "property |
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364 | * group" will move the object to the edge of the "property group" and shift the whole group |
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365 | * to achieve the designated index for the object to move. |
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366 | * @since 0.5 |
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367 | * |
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368 | * @param PropertyIdProvider $object |
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369 | * @param int $toIndex Absolute index where to move the object to. |
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370 | * |
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371 | * @throws OutOfBoundsException |
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372 | * @throws RuntimeException |
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373 | 47 | */ |
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374 | 47 | public function moveObjectToIndex( $object, $toIndex ) { |
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401 | |||
402 | /** |
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403 | * Adds an object at a specific index. If no index is specified, the object will be append to |
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404 | * the end of its "property group" or - if no objects featuring the same property exist - to the |
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405 | * absolute end of the array. |
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406 | * Specifying an index outside a "property group" will place the new object at the specified |
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407 | * index with the existing "property group" objects being shifted towards the new object. |
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408 | * |
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409 | * @since 0.5 |
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410 | * |
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411 | * @param PropertyIdProvider $object |
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412 | * @param int|null $index Absolute index where to place the new object. |
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413 | * |
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414 | 7 | * @throws RuntimeException |
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415 | 7 | */ |
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416 | public function addObjectAtIndex( $object, $index = null ) { |
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441 | |||
442 | /** |
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443 | * Adds an object to an existing property group at the specified absolute index. |
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444 | * |
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445 | * @param PropertyIdProvider $object |
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446 | * @param int|null $index |
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447 | * |
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448 | 3 | * @throws OutOfBoundsException |
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449 | */ |
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450 | 3 | private function addObjectToPropertyGroup( $object, $index = null ) { |
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487 | |||
488 | } |
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489 |
There are different options of fixing this problem.
If you want to be on the safe side, you can add an additional type-check:
If you are sure that the expression is traversable, you might want to add a doc comment cast to improve IDE auto-completion and static analysis:
Mark the issue as a false-positive: Just hover the remove button, in the top-right corner of this issue for more options.