Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like WC_Order_Item 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 WC_Order_Item, and based on these observations, apply Extract Interface, too.
1 | <?php |
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17 | class WC_Order_Item extends WC_Data implements ArrayAccess { |
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18 | |||
19 | /** |
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20 | * Order Data array. This is the core order data exposed in APIs since 2.7.0. |
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21 | * @since 2.7.0 |
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22 | * @var array |
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23 | */ |
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24 | protected $_data = array( |
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25 | 'order_id' => 0, |
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26 | 'id' => 0, // order_item_id |
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27 | 'name' => '', |
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28 | 'type' => '', |
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29 | ); |
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30 | |||
31 | /** |
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32 | * May store an order to prevent retriving it multiple times. |
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33 | * @var object |
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34 | */ |
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35 | protected $_order; |
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36 | |||
37 | /** |
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38 | * Stores meta in cache for future reads. |
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39 | * A group must be set to to enable caching. |
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40 | * @var string |
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41 | */ |
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42 | protected $_cache_group = 'order_itemmeta'; |
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43 | |||
44 | /** |
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45 | * Meta type. This should match up with |
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46 | * the types avaiable at https://codex.wordpress.org/Function_Reference/add_metadata. |
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47 | * WP defines 'post', 'user', 'comment', and 'term'. |
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48 | */ |
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49 | protected $_meta_type = 'order_item'; |
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50 | |||
51 | /** |
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52 | * Constructor. |
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53 | * @param int|object|array $read ID to load from the DB (optional) or already queried data. |
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54 | */ |
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55 | public function __construct( $read = 0 ) { |
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68 | |||
69 | /** |
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70 | * Type checking |
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71 | * @param string|array $Type |
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72 | * @return boolean |
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73 | */ |
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74 | public function is_type( $type ) { |
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77 | |||
78 | /** |
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79 | * Get quantity. |
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80 | * @return int |
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81 | */ |
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82 | public function get_quantity() { |
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85 | |||
86 | /** |
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87 | * Get parent order object. |
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88 | * @return int |
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89 | */ |
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90 | public function get_order() { |
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96 | |||
97 | /* |
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98 | |-------------------------------------------------------------------------- |
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99 | | Getters |
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100 | |-------------------------------------------------------------------------- |
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101 | */ |
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102 | |||
103 | /** |
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104 | * Get order item ID. |
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105 | * @return int |
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106 | */ |
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107 | public function get_id() { |
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110 | |||
111 | /** |
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112 | * Get order ID this meta belongs to. |
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113 | * @return int |
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114 | */ |
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115 | public function get_order_id() { |
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118 | |||
119 | /** |
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120 | * Get order item name. |
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121 | * @return string |
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122 | */ |
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123 | public function get_name() { |
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126 | |||
127 | /** |
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128 | * Get order item type. |
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129 | * @return string |
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130 | */ |
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131 | public function get_type() { |
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134 | |||
135 | /* |
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136 | |-------------------------------------------------------------------------- |
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137 | | Setters |
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138 | |-------------------------------------------------------------------------- |
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139 | */ |
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140 | |||
141 | /** |
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142 | * Set ID |
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143 | * @param int $value |
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144 | * @throws WC_Data_Exception |
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145 | */ |
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146 | public function set_id( $value ) { |
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149 | |||
150 | /** |
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151 | * Set order ID. |
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152 | * @param int $value |
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153 | * @throws WC_Data_Exception |
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154 | */ |
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155 | public function set_order_id( $value ) { |
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158 | |||
159 | /** |
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160 | * Set order item name. |
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161 | * @param string $value |
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162 | * @throws WC_Data_Exception |
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163 | */ |
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164 | public function set_name( $value ) { |
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167 | |||
168 | /** |
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169 | * Set order item type. |
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170 | * @param string $value |
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171 | * @throws WC_Data_Exception |
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172 | */ |
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173 | protected function set_type( $value ) { |
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176 | |||
177 | /* |
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178 | |-------------------------------------------------------------------------- |
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179 | | CRUD methods |
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180 | |-------------------------------------------------------------------------- |
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181 | | |
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182 | | Methods which create, read, update and delete data from the database. |
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183 | | |
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184 | */ |
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185 | |||
186 | /** |
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187 | * Insert data into the database. |
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188 | * @since 2.7.0 |
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189 | */ |
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190 | View Code Duplication | public function create() { |
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202 | |||
203 | /** |
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204 | * Update data in the database. |
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205 | * @since 2.7.0 |
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206 | */ |
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207 | View Code Duplication | public function update() { |
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218 | |||
219 | /** |
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220 | * Read from the database. |
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221 | * @since 2.7.0 |
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222 | * @param int|object $item ID of object to read, or already queried object. |
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223 | */ |
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224 | public function read( $item ) { |
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249 | |||
250 | /** |
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251 | * Save data to the database. |
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252 | * @since 2.7.0 |
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253 | * @return int Item ID |
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254 | */ |
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255 | public function save() { |
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265 | |||
266 | /** |
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267 | * Delete data from the database. |
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268 | * @since 2.7.0 |
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269 | */ |
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270 | public function delete() { |
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279 | |||
280 | /* |
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281 | |-------------------------------------------------------------------------- |
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282 | | Meta Data Handling |
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283 | |-------------------------------------------------------------------------- |
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284 | */ |
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285 | |||
286 | /** |
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287 | * Expands things like term slugs before return. |
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288 | * @param string $hideprefix (default: _) |
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289 | * @return array |
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290 | */ |
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291 | public function get_formatted_meta_data( $hideprefix = '_' ) { |
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323 | |||
324 | /* |
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325 | |-------------------------------------------------------------------------- |
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326 | | Array Access Methods |
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327 | |-------------------------------------------------------------------------- |
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328 | | |
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329 | | For backwards compat with legacy arrays. |
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330 | | |
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331 | */ |
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332 | |||
333 | /** |
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334 | * offsetSet for ArrayAccess |
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335 | * @param string $offset |
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336 | * @param mixed $value |
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337 | */ |
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338 | public function offsetSet( $offset, $value ) { |
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352 | |||
353 | /** |
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354 | * offsetUnset for ArrayAccess |
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355 | * @param string $offset |
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356 | */ |
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357 | public function offsetUnset( $offset ) { |
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369 | |||
370 | /** |
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371 | * offsetExists for ArrayAccess |
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372 | * @param string $offset |
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373 | * @return bool |
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374 | */ |
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375 | public function offsetExists( $offset ) { |
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381 | |||
382 | /** |
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383 | * offsetGet for ArrayAccess |
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384 | * @param string $offset |
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385 | * @return mixed |
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386 | */ |
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387 | public function offsetGet( $offset ) { |
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411 | } |
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412 |
This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function.
Consider the following example. The parameter
$italy
is not defined by the methodfinale(...)
.The most likely cause is that the parameter was removed, but the annotation was not.