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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43 | final class Query implements IteratorAggregate |
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44 | { |
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45 | public const TYPE_FIND = 1; |
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46 | public const TYPE_FIND_AND_UPDATE = 2; |
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47 | public const TYPE_FIND_AND_REMOVE = 3; |
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48 | public const TYPE_INSERT = 4; |
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49 | public const TYPE_UPDATE = 5; |
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50 | public const TYPE_REMOVE = 6; |
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51 | public const TYPE_DISTINCT = 9; |
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52 | public const TYPE_COUNT = 11; |
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53 | |||
54 | public const HINT_REFRESH = 1; |
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55 | // 2 was used for HINT_SLAVE_OKAY, which was removed in 2.0 |
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56 | public const HINT_READ_PREFERENCE = 3; |
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57 | public const HINT_READ_ONLY = 5; |
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58 | |||
59 | /** |
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60 | * The DocumentManager instance. |
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61 | * |
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62 | * @var DocumentManager |
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63 | */ |
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64 | private $dm; |
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65 | |||
66 | /** |
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67 | * The ClassMetadata instance. |
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68 | * |
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69 | * @var ClassMetadata |
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70 | */ |
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71 | private $class; |
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72 | |||
73 | /** |
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74 | * Whether to hydrate results as document class instances. |
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75 | * |
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76 | * @var bool |
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77 | */ |
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78 | private $hydrate = true; |
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79 | |||
80 | /** |
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81 | * Array of primer Closure instances. |
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82 | * |
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83 | * @var array |
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84 | */ |
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85 | private $primers = []; |
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86 | |||
87 | /** |
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88 | * Hints for UnitOfWork behavior. |
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89 | * |
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90 | * @var array |
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91 | */ |
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92 | private $unitOfWorkHints = []; |
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93 | |||
94 | /** |
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95 | * The Collection instance. |
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96 | * |
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97 | * @var Collection |
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98 | */ |
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99 | protected $collection; |
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100 | |||
101 | /** |
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102 | * Query structure generated by the Builder class. |
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103 | * |
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104 | * @var array |
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105 | */ |
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106 | private $query; |
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107 | |||
108 | /** @var Iterator|null */ |
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109 | private $iterator; |
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110 | |||
111 | /** |
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112 | * Query options |
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113 | * |
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114 | * @var array |
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115 | */ |
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116 | private $options; |
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117 | |||
118 | public function __construct(DocumentManager $dm, ClassMetadata $class, Collection $collection, array $query = [], array $options = [], bool $hydrate = true, bool $refresh = false, array $primers = [], bool $readOnly = false) |
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119 | { |
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120 | $primers = array_filter($primers); |
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121 | |||
122 | switch ($query['type']) { |
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123 | 164 | case self::TYPE_FIND: |
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124 | case self::TYPE_FIND_AND_UPDATE: |
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125 | 164 | case self::TYPE_FIND_AND_REMOVE: |
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126 | case self::TYPE_INSERT: |
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127 | case self::TYPE_UPDATE: |
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128 | case self::TYPE_REMOVE: |
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129 | 164 | case self::TYPE_DISTINCT: |
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130 | case self::TYPE_COUNT: |
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131 | 164 | break; |
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132 | 164 | ||
133 | 39 | default: |
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134 | 27 | throw new InvalidArgumentException('Invalid query type: ' . $query['type']); |
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135 | 24 | } |
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136 | 23 | ||
137 | 8 | $this->collection = $collection; |
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138 | 6 | $this->query = $query; |
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139 | 4 | $this->options = $options; |
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140 | 163 | $this->dm = $dm; |
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141 | $this->class = $class; |
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142 | $this->hydrate = $hydrate; |
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143 | 1 | $this->primers = $primers; |
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144 | |||
145 | $this->setReadOnly($readOnly); |
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146 | 163 | $this->setRefresh($refresh); |
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147 | 163 | ||
148 | 163 | if (! isset($query['readPreference'])) { |
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149 | 163 | return; |
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150 | 163 | } |
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151 | 163 | ||
152 | 163 | $this->unitOfWorkHints[self::HINT_READ_PREFERENCE] = $query['readPreference']; |
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153 | } |
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154 | 163 | ||
155 | 163 | public function __clone() |
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159 | |||
160 | /** |
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161 | 6 | * Return an array of information about the query structure for debugging. |
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162 | 6 | * |
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163 | * The $name parameter may be used to return a specific key from the |
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164 | 64 | * internal $query array property. If omitted, the entire array will be |
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165 | * returned. |
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166 | 64 | */ |
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167 | 64 | public function debug(?string $name = null) |
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168 | { |
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169 | return $name !== null ? $this->query[$name] : $this->query; |
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170 | } |
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171 | |||
172 | /** |
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173 | * Execute the query and returns the results. |
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174 | * |
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175 | * @return Iterator|UpdateResult|InsertOneResult|DeleteResult|array|object|int|null |
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176 | 27 | * |
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177 | * @throws MongoDBException |
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178 | 27 | */ |
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179 | public function execute() |
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180 | { |
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181 | $results = $this->runQuery(); |
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182 | |||
183 | if (! $this->hydrate) { |
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184 | return $results; |
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185 | } |
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186 | |||
187 | $uow = $this->dm->getUnitOfWork(); |
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188 | 123 | ||
189 | /* If a single document is returned from a findAndModify command and it |
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190 | 123 | * includes the identifier field, attempt hydration. |
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191 | */ |
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192 | 122 | if (($this->query['type'] === self::TYPE_FIND_AND_UPDATE || |
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193 | 9 | $this->query['type'] === self::TYPE_FIND_AND_REMOVE) && |
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194 | is_array($results) && isset($results['_id'])) { |
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195 | $results = $uow->getOrCreateDocument($this->class->name, $results, $this->unitOfWorkHints); |
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196 | 116 | ||
197 | if (! empty($this->primers)) { |
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198 | $referencePrimer = new ReferencePrimer($this->dm, $uow); |
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199 | |||
200 | foreach ($this->primers as $fieldName => $primer) { |
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201 | 116 | $primer = is_callable($primer) ? $primer : null; |
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202 | 116 | $referencePrimer->primeReferences($this->class, [$results], $fieldName, $this->unitOfWorkHints, $primer); |
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203 | 116 | } |
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204 | 5 | } |
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205 | } |
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206 | 5 | ||
207 | 1 | return $results; |
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208 | } |
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209 | 1 | ||
210 | 1 | /** |
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211 | 1 | * Gets the ClassMetadata instance. |
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212 | */ |
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213 | public function getClass() : ClassMetadata |
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214 | { |
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215 | return $this->class; |
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216 | 116 | } |
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217 | |||
218 | public function getDocumentManager() : DocumentManager |
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219 | { |
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220 | return $this->dm; |
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221 | } |
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222 | |||
223 | /** |
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224 | * Execute the query and return its result, which must be an Iterator. |
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225 | * |
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226 | * If the query type is not expected to return an Iterator, |
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227 | * BadMethodCallException will be thrown before executing the query. |
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228 | * Otherwise, the query will be executed and UnexpectedValueException will |
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229 | * be thrown if {@link Query::execute()} does not return an Iterator. |
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230 | * |
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231 | * @see http://php.net/manual/en/iteratoraggregate.getiterator.php |
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232 | * |
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233 | * @throws BadMethodCallException If the query type would not return an Iterator. |
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234 | * @throws UnexpectedValueException If the query did not return an Iterator. |
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235 | * @throws MongoDBException |
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236 | */ |
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237 | public function getIterator() : Iterator |
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238 | { |
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239 | switch ($this->query['type']) { |
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240 | case self::TYPE_FIND: |
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241 | case self::TYPE_DISTINCT: |
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242 | break; |
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243 | |||
244 | default: |
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245 | throw new BadMethodCallException('Iterator would not be returned for query type: ' . $this->query['type']); |
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246 | 83 | } |
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247 | |||
248 | 83 | if ($this->iterator === null) { |
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249 | 83 | $result = $this->execute(); |
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250 | 6 | if (! $result instanceof Iterator) { |
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251 | 77 | throw new UnexpectedValueException('Iterator was not returned for query type: ' . $this->query['type']); |
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252 | } |
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253 | $this->iterator = $result; |
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254 | 6 | } |
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255 | |||
256 | return $this->iterator; |
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257 | 77 | } |
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258 | 77 | ||
259 | 77 | /** |
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260 | * Return the query structure. |
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261 | */ |
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262 | 77 | public function getQuery() : array |
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266 | |||
267 | /** |
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268 | * Execute the query and return the first result. |
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269 | * |
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270 | * @return array|object|null |
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271 | 14 | */ |
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272 | public function getSingleResult() |
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273 | 14 | { |
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274 | $clonedQuery = clone $this; |
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275 | $clonedQuery->query['limit'] = 1; |
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276 | return $clonedQuery->getIterator()->current() ?: null; |
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277 | } |
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278 | |||
279 | /** |
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280 | * Return the query type. |
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281 | 64 | */ |
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282 | public function getType() : int |
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283 | 64 | { |
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284 | 64 | return $this->query['type']; |
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285 | 64 | } |
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286 | |||
287 | /** |
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288 | * Sets whether or not to hydrate the documents to objects. |
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289 | */ |
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290 | public function setHydrate(bool $hydrate) : void |
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291 | { |
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292 | $this->hydrate = $hydrate; |
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293 | } |
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294 | |||
295 | /** |
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296 | * Set whether documents should be registered in UnitOfWork. If document would |
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297 | * already be managed it will be left intact and new instance returned. |
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298 | * |
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299 | * This option has no effect if hydration is disabled. |
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300 | */ |
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301 | public function setReadOnly(bool $readOnly) : void |
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302 | { |
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303 | $this->unitOfWorkHints[self::HINT_READ_ONLY] = $readOnly; |
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304 | } |
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305 | |||
306 | /** |
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307 | * Set whether to refresh hydrated documents that are already in the |
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308 | * identity map. |
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309 | * |
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310 | 163 | * This option has no effect if hydration is disabled. |
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311 | */ |
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312 | 163 | public function setRefresh(bool $refresh) : void |
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313 | 163 | { |
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314 | $this->unitOfWorkHints[self::HINT_REFRESH] = $refresh; |
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315 | } |
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316 | |||
317 | /** |
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318 | * Execute the query and return its results as an array. |
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319 | * |
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320 | * @see IteratorAggregate::toArray() |
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321 | 163 | */ |
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322 | public function toArray() : array |
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326 | |||
327 | /** |
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328 | * Returns an array containing the specified keys and their values from the |
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329 | * query array, provided they exist and are not null. |
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330 | */ |
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331 | 11 | private function getQueryOptions(string ...$keys) : array |
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332 | { |
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333 | 11 | return array_filter( |
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334 | array_intersect_key($this->query, array_flip($keys)), |
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335 | static function ($value) { |
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336 | return $value !== null; |
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337 | } |
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340 | 121 | ||
341 | private function makeIterator(Cursor $cursor) : Iterator |
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356 | 106 | ||
357 | /** |
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358 | 106 | * Returns an array with its keys renamed based on the translation map. |
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359 | 20 | * |
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360 | 20 | * @return array $rename Translation map (from => to) for renaming keys |
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361 | */ |
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362 | private function renameQueryOptions(array $options, array $rename) : array |
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383 | |||
384 | 82 | /** |
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385 | * Execute the query and return its result. |
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386 | * |
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387 | * The return value will vary based on the query type. Commands with results |
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388 | 82 | * (e.g. aggregate, inline mapReduce) may return an ArrayIterator. Other |
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389 | * commands and operations may return a status array or a boolean, depending |
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390 | 82 | * on the driver's write concern. Queries and some mapReduce commands will |
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391 | * return an Iterator. |
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392 | * |
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393 | * @return Iterator|UpdateResult|InsertOneResult|DeleteResult|array|object|int|null |
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394 | */ |
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395 | public function runQuery() |
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489 | 2 | ||
490 | 2 | private function isFirstKeyUpdateOperator() : bool |
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497 | } |
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498 |
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: