Complex classes like ShoppingCart 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 ShoppingCart, and based on these observations, apply Extract Interface, too.
1 | <?php |
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24 | class ShoppingCart extends \yz\shoppingcart\ShoppingCart |
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25 | { |
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26 | /** |
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27 | * @var AbstractCartPosition[] |
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28 | * TODO make local AbstractCartPosition |
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29 | */ |
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30 | protected $_positions = []; |
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31 | |||
32 | /** |
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33 | * The cart module. |
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34 | */ |
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35 | public $module; |
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36 | |||
37 | public function behaviors() |
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45 | |||
46 | 1 | /** |
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47 | 1 | * @return integer |
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48 | 1 | */ |
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49 | public function getCount(): int |
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60 | |||
61 | 2 | public function findRelatedFor(CartPositionInterface $parent): ?CartPositionInterface |
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71 | 1 | ||
72 | /** |
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73 | * @return CartPositionInterface[] |
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74 | */ |
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75 | public function getRootPositions(): array |
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81 | |||
82 | public function getQuantity() |
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91 | |||
92 | public function getSubtotal() |
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96 | |||
97 | public function getTotal() |
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101 | |||
102 | public function getDiscount() |
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106 | |||
107 | public function formatCurrency($sum, $currency = null) |
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111 | |||
112 | /** |
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113 | * Sets cart from serialized string |
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114 | * @param string $serialized |
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115 | */ |
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116 | public function setSerialized($serialized) |
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126 | |||
127 | /** |
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128 | * Checks whether any of cart positions has error in `id` attribute. |
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129 | * @return boolean |
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130 | */ |
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131 | public function hasErrors() |
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141 | |||
142 | /** |
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143 | * @param CartPositionInterface[] $positions |
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144 | */ |
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145 | public function putPositions($positions) |
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168 | |||
169 | public function getCurrency(): ?string |
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177 | |||
178 | /** |
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179 | * @return array |
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180 | */ |
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181 | public function getAdditionalLinks(): array |
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203 | |||
204 | /** |
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205 | * @var CartActionEvent[]|null |
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206 | */ |
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207 | private $_accumulatedEvents; |
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208 | public function trigger($name, Event $event = null) |
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217 | |||
218 | /** |
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219 | * Runs $closure and accumulates all events occurred during $closure run. |
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220 | * Events get released immediately after a success $closure run. |
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221 | * |
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222 | * The method can be used to prevent useless calculations that happen after |
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223 | * bunch of similar updates on a cart. |
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224 | * |
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225 | * @param \Closure $closure |
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226 | */ |
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227 | public function accumulateEvents(\Closure $closure): void |
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242 | } |
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243 |
This check marks access to variables or properties that have not been declared yet. While PHP has no explicit notion of declaring a variable, accessing it before a value is assigned to it is most likely a bug.