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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| 23 | class ShoppingCart extends \yz\shoppingcart\ShoppingCart |
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| 24 | { |
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| 25 | /** |
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| 26 | * @var AbstractCartPosition[] |
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| 27 | * TODO make local AbstractCartPosition |
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| 28 | */ |
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| 29 | protected $_positions = []; |
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| 30 | |||
| 31 | /** |
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| 32 | * The cart module. |
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| 33 | */ |
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| 34 | public $module; |
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| 35 | |||
| 36 | /** |
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| 37 | * @return integer |
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| 38 | */ |
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| 39 | 1 | public function getCount(): int |
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| 50 | |||
| 51 | 1 | public function findRelatedFor(CartPositionInterface $parent): ?CartPositionInterface |
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| 61 | 2 | ||
| 62 | /** |
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| 63 | * @return CartPositionInterface[] |
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| 64 | 1 | */ |
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| 65 | public function getRootPositions(): array |
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| 71 | 1 | ||
| 72 | public function getQuantity() |
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| 81 | |||
| 82 | public function getSubtotal() |
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| 86 | |||
| 87 | public function getTotal() |
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| 91 | |||
| 92 | public function getDiscount() |
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| 96 | |||
| 97 | public function formatCurrency($sum, $currency = null) |
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| 101 | |||
| 102 | /** |
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| 103 | * Sets cart from serialized string |
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| 104 | * @param string $serialized |
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| 105 | */ |
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| 106 | public function setSerialized($serialized) |
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| 116 | |||
| 117 | /** |
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| 118 | * Checks whether any of cart positions has error in `id` attribute. |
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| 119 | * @return boolean |
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| 120 | */ |
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| 121 | public function hasErrors() |
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| 131 | |||
| 132 | /** |
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| 133 | * @param CartPositionInterface[] $positions |
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| 134 | */ |
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| 135 | public function putPositions($positions) |
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| 158 | |||
| 159 | public function getCurrency(): ?string |
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| 167 | |||
| 168 | /** |
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| 169 | * @return array |
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| 170 | */ |
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| 171 | public function getAdditionalLinks(): array |
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| 193 | |||
| 194 | /** |
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| 195 | * @var CartActionEvent[]|null |
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| 196 | */ |
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| 197 | private $_accumulatedEvents; |
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| 198 | public function trigger($name, Event $event = null) |
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| 207 | |||
| 208 | /** |
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| 209 | * Runs $closure and accumulates all events occurred during $closure run. |
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| 210 | * Events get released immediately after a success $closure run. |
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| 211 | * |
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| 212 | * The method can be used to prevent useless calculations that happen after |
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| 213 | * bunch of similar updates on a cart. |
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| 214 | * |
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| 215 | * @param \Closure $closure |
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| 216 | */ |
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| 217 | public function accumulateEvents(\Closure $closure): void |
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| 232 | } |
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| 233 |
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.