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 WPInv_Subscriptions 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 WPInv_Subscriptions, and based on these observations, apply Extract Interface, too.
1 | <?php |
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15 | class WPInv_Subscriptions { |
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16 | |||
17 | private static $instance; |
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18 | |||
19 | /** |
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20 | * Main WPInv_Subscriptions Instance |
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21 | */ |
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22 | public static function instance() { |
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31 | |||
32 | /** |
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33 | * Constructor -- prevent new instances |
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34 | * |
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35 | * @since 1.0.0 |
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36 | */ |
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37 | private function __construct(){ |
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40 | |||
41 | /** |
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42 | * Get things started |
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43 | * |
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44 | * Sets up inits actions and filters |
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45 | * |
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46 | * @since 1.0.0 |
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47 | */ |
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48 | function init() { |
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55 | |||
56 | /** |
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57 | * Setup plugin constants. |
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58 | * |
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59 | * @access private |
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60 | * @since 1.0.0 |
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61 | * @return void |
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62 | */ |
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63 | private function setup_constants() { |
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70 | |||
71 | /** |
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72 | * Add our actions |
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73 | * |
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74 | * @since 1.0.0 |
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75 | * @return void |
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76 | */ |
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77 | private function actions() { |
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87 | |||
88 | /** |
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89 | * Add our filters |
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90 | * |
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91 | * @since 1.0 |
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92 | * @return void |
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93 | */ |
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94 | private function filters() { |
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97 | |||
98 | /** |
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99 | * Register our Subscriptions submenu |
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100 | * |
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101 | * @since 2.4 |
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102 | * @return void |
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103 | */ |
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104 | public function wpinv_subscriptions_list() { |
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114 | |||
115 | public function notices() { |
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151 | |||
152 | /** |
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153 | * Every wpinv_action present in $_GET is called using WordPress's do_action function. |
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154 | * These functions are called on init. |
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155 | * |
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156 | * @since 1.0.0 |
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157 | * @return void |
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158 | */ |
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159 | function wpinv_get_actions() { |
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164 | |||
165 | /** |
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166 | * Every wpinv_action present in $_POST is called using WordPress's do_action function. |
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167 | * These functions are called on init. |
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168 | * |
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169 | * @since 1.0.0 |
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170 | * @return void |
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171 | */ |
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172 | function wpinv_post_actions() { |
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177 | |||
178 | /** |
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179 | * Get pretty subscription frequency |
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180 | * |
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181 | * @param $period |
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182 | * @param int $frequency_count The frequency of the period. |
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183 | * @return mixed|string|void |
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184 | */ |
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185 | public static function wpinv_get_pretty_subscription_frequency( $period, $frequency_count = 1) { |
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209 | |||
210 | /** |
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211 | * Handles cancellation requests for a subscription |
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212 | * |
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213 | * @access public |
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214 | * @since 1.0.0 |
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215 | * @return void |
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216 | */ |
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217 | public function wpinv_process_cancellation( $data ) { |
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264 | |||
265 | /** |
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266 | * Create/Update subscription on invoice created/updated |
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267 | * |
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268 | * @access public |
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269 | * @since 1.0.0 |
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270 | * @return void |
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271 | */ |
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272 | public function wpinv_add_update_subscription( $invoice_id, $post ) { |
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344 | } |
Adding explicit visibility (
private
,protected
, orpublic
) is generally recommend to communicate to other developers how, and from where this method is intended to be used.