Complex classes like Query 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 Query, and based on these observations, apply Extract Interface, too.
1 | <?php |
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44 | final class Query implements IteratorAggregate |
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45 | { |
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46 | public const TYPE_FIND = 1; |
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47 | public const TYPE_FIND_AND_UPDATE = 2; |
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48 | public const TYPE_FIND_AND_REMOVE = 3; |
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49 | public const TYPE_INSERT = 4; |
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50 | public const TYPE_UPDATE = 5; |
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51 | public const TYPE_REMOVE = 6; |
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52 | public const TYPE_DISTINCT = 9; |
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53 | public const TYPE_COUNT = 11; |
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54 | |||
55 | public const HINT_REFRESH = 1; |
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56 | // 2 was used for HINT_SLAVE_OKAY, which was removed in 2.0 |
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57 | public const HINT_READ_PREFERENCE = 3; |
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58 | public const HINT_READ_ONLY = 5; |
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59 | |||
60 | /** |
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61 | * The DocumentManager instance. |
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62 | * |
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63 | * @var DocumentManager |
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64 | */ |
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65 | private $dm; |
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66 | |||
67 | /** |
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68 | * The ClassMetadata instance. |
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69 | * |
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70 | * @var ClassMetadata |
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71 | */ |
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72 | private $class; |
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73 | |||
74 | /** |
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75 | * Whether to hydrate results as document class instances. |
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76 | * |
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77 | * @var bool |
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78 | */ |
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79 | private $hydrate = true; |
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80 | |||
81 | /** |
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82 | * Array of primer Closure instances. |
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83 | * |
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84 | * @var array |
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85 | */ |
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86 | private $primers = []; |
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87 | |||
88 | /** @var bool */ |
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89 | private $rewindable = true; |
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90 | |||
91 | /** |
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92 | * Hints for UnitOfWork behavior. |
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93 | * |
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94 | * @var array |
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95 | */ |
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96 | private $unitOfWorkHints = []; |
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97 | |||
98 | /** |
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99 | * The Collection instance. |
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100 | * |
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101 | * @var Collection |
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102 | */ |
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103 | protected $collection; |
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104 | |||
105 | /** |
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106 | * Query structure generated by the Builder class. |
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107 | * |
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108 | * @var array |
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109 | */ |
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110 | private $query; |
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111 | |||
112 | /** @var Iterator|null */ |
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113 | private $iterator; |
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114 | |||
115 | /** |
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116 | * Query options |
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117 | * |
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118 | * @var array |
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119 | */ |
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120 | private $options; |
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121 | |||
122 | 168 | public function __construct(DocumentManager $dm, ClassMetadata $class, Collection $collection, array $query = [], array $options = [], bool $hydrate = true, bool $refresh = false, array $primers = [], bool $readOnly = false, bool $rewindable = true) |
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159 | |||
160 | 64 | public function __clone() |
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164 | |||
165 | /** |
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166 | * Return an array of information about the query structure for debugging. |
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167 | * |
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168 | * The $name parameter may be used to return a specific key from the |
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169 | * internal $query array property. If omitted, the entire array will be |
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170 | * returned. |
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171 | */ |
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172 | 27 | public function debug(?string $name = null) |
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176 | |||
177 | /** |
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178 | * Execute the query and returns the results. |
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179 | * |
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180 | * @return Iterator|UpdateResult|InsertOneResult|DeleteResult|array|object|int|null |
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181 | * |
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182 | * @throws MongoDBException |
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183 | */ |
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184 | 127 | public function execute() |
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214 | |||
215 | /** |
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216 | * Gets the ClassMetadata instance. |
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217 | */ |
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218 | public function getClass() : ClassMetadata |
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222 | |||
223 | public function getDocumentManager() : DocumentManager |
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227 | |||
228 | /** |
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229 | * Execute the query and return its result, which must be an Iterator. |
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230 | * |
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231 | * If the query type is not expected to return an Iterator, |
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232 | * BadMethodCallException will be thrown before executing the query. |
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233 | * Otherwise, the query will be executed and UnexpectedValueException will |
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234 | * be thrown if {@link Query::execute()} does not return an Iterator. |
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235 | * |
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236 | * @see http://php.net/manual/en/iteratoraggregate.getiterator.php |
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237 | * |
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238 | * @throws BadMethodCallException If the query type would not return an Iterator. |
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239 | * @throws UnexpectedValueException If the query did not return an Iterator. |
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240 | * @throws MongoDBException |
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241 | */ |
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242 | 84 | public function getIterator() : Iterator |
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263 | |||
264 | /** |
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265 | * Return the query structure. |
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266 | */ |
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267 | 14 | public function getQuery() : array |
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271 | |||
272 | /** |
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273 | * Execute the query and return the first result. |
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274 | * |
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275 | * @return array|object|null |
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276 | */ |
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277 | 64 | public function getSingleResult() |
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284 | |||
285 | /** |
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286 | * Return the query type. |
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287 | */ |
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288 | public function getType() : int |
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292 | |||
293 | /** |
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294 | * Sets whether or not to hydrate the documents to objects. |
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295 | */ |
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296 | 1 | public function setHydrate(bool $hydrate) : void |
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297 | { |
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298 | 1 | $this->hydrate = $hydrate; |
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299 | 1 | } |
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300 | |||
301 | /** |
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302 | * Set whether documents should be registered in UnitOfWork. If document would |
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303 | * already be managed it will be left intact and new instance returned. |
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304 | * |
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305 | * This option has no effect if hydration is disabled. |
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306 | */ |
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307 | 167 | public function setReadOnly(bool $readOnly) : void |
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311 | |||
312 | /** |
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313 | * Set whether to refresh hydrated documents that are already in the |
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314 | * identity map. |
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315 | * |
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316 | * This option has no effect if hydration is disabled. |
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317 | */ |
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318 | 167 | public function setRefresh(bool $refresh) : void |
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322 | |||
323 | /** |
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324 | * Set to enable wrapping of resulting Iterator with CachingIterator |
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325 | */ |
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326 | 167 | public function setRewindable(bool $rewindable = true) : void |
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330 | |||
331 | /** |
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332 | * Execute the query and return its results as an array. |
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333 | * |
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334 | * @see IteratorAggregate::toArray() |
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335 | */ |
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336 | 11 | public function toArray() : array |
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340 | |||
341 | /** |
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342 | * Returns an array containing the specified keys and their values from the |
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343 | * query array, provided they exist and are not null. |
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344 | */ |
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345 | 125 | private function getQueryOptions(string ...$keys) : array |
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354 | |||
355 | /** |
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356 | * Decorate the cursor with caching, hydration, and priming behavior. |
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357 | * |
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358 | * Note: while this method could strictly take a MongoDB\Driver\Cursor, we |
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359 | * accept Traversable for testing purposes since Cursor cannot be mocked. |
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360 | * HydratingIterator, CachingIterator, and BaseIterator expect a Traversable |
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361 | * so this should not have any adverse effects. |
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362 | */ |
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363 | 111 | private function makeIterator(Traversable $cursor) : Iterator |
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378 | |||
379 | /** |
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380 | * Returns an array with its keys renamed based on the translation map. |
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381 | * |
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382 | * @return array $rename Translation map (from => to) for renaming keys |
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383 | */ |
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384 | 116 | private function renameQueryOptions(array $options, array $rename) : array |
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405 | |||
406 | /** |
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407 | * Execute the query and return its result. |
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408 | * |
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409 | * The return value will vary based on the query type. Commands with results |
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410 | * (e.g. aggregate, inline mapReduce) may return an ArrayIterator. Other |
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411 | * commands and operations may return a status array or a boolean, depending |
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412 | * on the driver's write concern. Queries and some mapReduce commands will |
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413 | * return an Iterator. |
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414 | * |
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415 | * @return Iterator|UpdateResult|InsertOneResult|DeleteResult|array|object|int|null |
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416 | */ |
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417 | 127 | private function runQuery() |
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503 | |||
504 | 19 | private function isFirstKeyUpdateOperator() : bool |
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511 | } |
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512 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: