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_Gateway_Stripe_Bitcoin 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_Gateway_Stripe_Bitcoin, and based on these observations, apply Extract Interface, too.
1 | <?php |
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13 | class WC_Gateway_Stripe_Bitcoin extends WC_Stripe_Payment_Gateway { |
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14 | /** |
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15 | * Notices (array) |
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16 | * @var array |
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17 | */ |
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18 | public $notices = array(); |
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19 | |||
20 | /** |
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21 | * Is test mode active? |
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22 | * |
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23 | * @var bool |
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24 | */ |
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25 | public $testmode; |
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26 | |||
27 | /** |
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28 | * Alternate credit card statement name |
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29 | * |
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30 | * @var bool |
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31 | */ |
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32 | public $statement_descriptor; |
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33 | |||
34 | /** |
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35 | * API access secret key |
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36 | * |
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37 | * @var string |
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38 | */ |
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39 | public $secret_key; |
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40 | |||
41 | /** |
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42 | * Api access publishable key |
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43 | * |
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44 | * @var string |
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45 | */ |
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46 | public $publishable_key; |
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47 | |||
48 | /** |
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49 | * Should we store the users credit cards? |
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50 | * |
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51 | * @var bool |
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52 | */ |
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53 | public $saved_cards; |
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54 | |||
55 | /** |
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56 | * Instructions for Bitcoin payment. |
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57 | * |
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58 | * @var string |
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59 | */ |
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60 | public $instructions; |
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61 | |||
62 | /** |
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63 | * Constructor |
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64 | */ |
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65 | public function __construct() { |
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105 | |||
106 | /** |
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107 | * Checks to make sure environment is setup correctly to use this payment method. |
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108 | * |
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109 | * @since 4.0.0 |
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110 | * @version 4.0.0 |
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111 | */ |
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112 | public function check_environment() { |
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129 | |||
130 | /** |
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131 | * Checks the environment for compatibility problems. Returns a string with the first incompatibility |
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132 | * found or false if the environment has no problems. |
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133 | * |
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134 | * @since 4.0.0 |
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135 | * @version 4.0.0 |
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136 | */ |
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137 | public function get_environment_warning() { |
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151 | |||
152 | /** |
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153 | * Returns all supported currencies for this payment method. |
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154 | * |
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155 | * @since 4.0.0 |
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156 | * @version 4.0.0 |
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157 | * @return array |
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158 | */ |
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159 | public function get_supported_currency() { |
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164 | |||
165 | /** |
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166 | * Checks to see if all criteria is met before showing payment method. |
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167 | * |
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168 | * @since 4.0.0 |
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169 | * @version 4.0.0 |
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170 | * @return bool |
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171 | */ |
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172 | public function is_available() { |
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179 | |||
180 | /** |
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181 | * Get_icon function. |
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182 | * |
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183 | * @since 1.0.0 |
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184 | * @version 4.0.0 |
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185 | * @return string |
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186 | */ |
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187 | public function get_icon() { |
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196 | |||
197 | /** |
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198 | * payment_scripts function. |
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199 | * |
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200 | * Outputs scripts used for stripe payment |
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201 | * |
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202 | * @access public |
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203 | */ |
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204 | public function payment_scripts() { |
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212 | |||
213 | /** |
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214 | * Initialize Gateway Settings Form Fields. |
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215 | */ |
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216 | public function init_form_fields() { |
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219 | |||
220 | /** |
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221 | * Payment form on checkout page |
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222 | */ |
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223 | public function payment_fields() { |
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251 | |||
252 | /** |
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253 | * Output for the order received page. |
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254 | * |
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255 | * @param int $order_id |
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256 | */ |
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257 | public function thankyou_page( $order_id ) { |
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260 | |||
261 | /** |
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262 | * Add content to the WC emails. |
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263 | * |
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264 | * @since 4.0.0 |
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265 | * @version 4.0.0 |
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266 | * @param WC_Order $order |
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267 | * @param bool $sent_to_admin |
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268 | * @param bool $plain_text |
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269 | */ |
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270 | public function email_instructions( $order, $sent_to_admin, $plain_text = false ) { |
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279 | |||
280 | /** |
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281 | * Gets the Bitcoin instructions for customer to pay. |
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282 | * |
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283 | * @since 4.0.0 |
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284 | * @version 4.0.0 |
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285 | * @param int $order_id |
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286 | */ |
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287 | public function get_instructions( $order_id, $plain_text = false ) { |
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326 | |||
327 | /** |
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328 | * Saves Bitcoin information to the order meta for later use. |
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329 | * |
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330 | * @since 4.0.0 |
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331 | * @version 4.0.0 |
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332 | * @param object $order |
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333 | * @param object $source_object |
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334 | */ |
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335 | public function save_instructions( $order, $source_object ) { |
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346 | |||
347 | /** |
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348 | * Process the payment |
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349 | * |
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350 | * @param int $order_id Reference. |
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351 | * @param bool $retry Should we retry on fail. |
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352 | * @param bool $force_save_source Force save the payment source. |
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353 | * |
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354 | * @throws Exception If payment will not be accepted. |
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355 | * |
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356 | * @return array|void |
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357 | */ |
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358 | public function process_payment( $order_id, $retry = true, $force_save_source = false ) { |
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416 | } |
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417 |
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVar
assignment in line 1 and the$higher
assignment in line 2 are dead. The first because$myVar
is never used and the second because$higher
is always overwritten for every possible time line.