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:
1 | <?php |
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8 | class Form |
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9 | { |
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10 | /** |
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11 | * @var Singleton The reference to *Singleton* instance of this class |
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12 | */ |
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13 | private static $instance; |
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14 | |||
15 | /** |
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16 | * @var Array Stores all the registered fields for each taxonomy |
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17 | */ |
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18 | private $fields = array(); |
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19 | |||
20 | /** |
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21 | * Returns the *Singleton* instance of this class. |
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22 | * |
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23 | * @return Singleton The *Singleton* instance. |
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24 | */ |
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25 | public static function get_instance() |
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33 | |||
34 | /** |
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35 | * Add a form field to both the add & edit forms for a given taxonomy. |
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36 | * |
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37 | * @param string $taxonomy_name |
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38 | * @param string $field_name |
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39 | * @param array $field_props |
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40 | * @throws \RuntimeException if duplicate names are registered under the same taxonomy |
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41 | */ |
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42 | public function add_field( $taxonomy_name, $field_name, $field_props ) |
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69 | |||
70 | /** |
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71 | * Render the 'edit term' form for a given taxonomy |
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72 | * |
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73 | * @param object $term Taxonomy term |
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74 | */ |
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75 | public function render_edit_form( $term ) |
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87 | |||
88 | /** |
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89 | * Render the 'add new term' form for a given taxonomy |
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90 | * |
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91 | * @param string $taxonomy Taxonomy name |
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92 | */ |
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93 | public function render_add_form( $taxonomy ) |
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104 | |||
105 | /** |
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106 | * Update the meta values for a given term. Called once one of the add/edit |
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107 | * forms is saved. |
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108 | * |
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109 | * @param type $term_id |
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110 | */ |
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111 | function update_term( $term_id ) |
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123 | |||
124 | /** |
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125 | * Add additional columns to the term table. |
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126 | * |
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127 | * @param array $columns |
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128 | * @return array |
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129 | */ |
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130 | View Code Duplication | function modify_table_columns( $columns ) |
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144 | |||
145 | /** |
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146 | * Retrieve the data for a given column in the term table. |
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147 | * |
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148 | * @see https://developer.wordpress.org/reference/hooks/manage_this-screen-taxonomy_custom_column/ |
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149 | * |
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150 | * @param type $content |
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151 | * @param type $column_name |
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152 | * @param type $term_id |
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153 | * @return type |
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154 | */ |
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155 | function modify_table_content( $content, $column_name, $term_id ) |
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172 | |||
173 | /** |
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174 | * Make custom table columns sortable. |
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175 | * |
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176 | * @param array $columns |
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177 | * @return string |
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178 | */ |
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179 | View Code Duplication | function modify_table_sortable_columns( $columns ) |
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194 | |||
195 | /** |
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196 | * Modify terms_clauses to allow sorting custom WordPress Admin Table Columns by a custom Taxonomy Term meta |
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197 | * |
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198 | * @see https://developer.wordpress.org/reference/hooks/terms_clauses/ |
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199 | * |
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200 | * @global type $wpdb |
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201 | * @param type $clauses |
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202 | * @param type $taxonomies |
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203 | * @param type $args |
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204 | * @return string |
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205 | */ |
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206 | function sort_custom_column( $clauses, $taxonomies, $args ) |
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225 | |||
226 | /** |
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227 | * Modify the orderby clauses for a given taxonomy |
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228 | * |
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229 | * @param array $clauses |
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230 | * @param string $taxonomy |
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231 | * @param string $termmeta |
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232 | */ |
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233 | function modify_term_clauses( &$clauses, $taxonomy, $termmeta ) |
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241 | |||
242 | /** |
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243 | * The default form field properties. This is merged with the user given |
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244 | * properties. When the component is rendered, this will be merged with the |
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245 | * component's properties as well. |
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246 | * |
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247 | * @return array |
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248 | */ |
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249 | private function default_props() |
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261 | } |
Let’s assume you have a class which uses late-static binding:
The code above will run fine in your PHP runtime. However, if you now create a sub-class and call the
getSomeVariable()
on that sub-class, you will receive a runtime error:In the case above, it makes sense to update
SomeClass
to useself
instead: