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 MinMaxModifier 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 MinMaxModifier, and based on these observations, apply Extract Interface, too.
1 | <?php |
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9 | class MinMaxModifier extends OrderModifier |
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10 | { |
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11 | |||
12 | //--------------------------------------------------------------------*** static variables |
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13 | |||
14 | private static $db = array( |
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15 | "Adjustments" => "HTMLText" |
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16 | ); |
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17 | |||
18 | private static $singular_name = "Stock Adjustment"; |
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19 | public function i18n_singular_name() |
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23 | |||
24 | private static $plural_name = "Stock Adjustments"; |
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25 | public function i18n_plural_name() |
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29 | |||
30 | private static $title = "MinMaxModifier"; |
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31 | |||
32 | private static $default_min_quantity = 1; |
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33 | |||
34 | private static $default_max_quantity = 9999; |
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35 | |||
36 | private static $min_field = "MinQuantity"; |
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37 | |||
38 | private static $max_field = "MaxQuantity"; |
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39 | |||
40 | private static $adjustment_message = "Based on stock availability, quantities have been adjusted as follows: "; |
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41 | |||
42 | private static $sorry_message = "Sorry, your selected value not is available."; |
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43 | |||
44 | private static $use_stock_quantities = true; |
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45 | |||
46 | private static $ids_of_items_adjusted = array(); |
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47 | |||
48 | //-------------------------------------------------------------------- *** static functions |
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49 | |||
50 | public static function show_form() |
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55 | |||
56 | public static function get_form($controller) |
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60 | |||
61 | //-------------------------------------------------------------------- *** cms fuctions |
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62 | |||
63 | public function getCMSFields() |
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70 | //-------------------------------------------------------------------- *** display functions |
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71 | public function CanBeRemoved() |
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75 | |||
76 | public function ShowInTable() |
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80 | |||
81 | |||
82 | //--------------------------------------------------------------------*** table values |
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83 | public function LiveCalculatedTotal() |
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88 | |||
89 | public function LiveTableValue() |
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93 | |||
94 | |||
95 | //--------------------------------------------------------------------*** table titles |
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96 | public function LiveName() |
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100 | |||
101 | //-------------------------------------------------------------------- *** calculations |
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102 | public static function apply_min_max() |
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208 | |||
209 | public function updateForAjax(array $js) |
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223 | |||
224 | |||
225 | //--------------------------------------------------------------------*** database functions |
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226 | } |
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227 |
You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.