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 Jetpack_Admin_Page 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 Jetpack_Admin_Page, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 4 | abstract class Jetpack_Admin_Page { |
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| 5 | // Add page specific actions given the page hook |
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| 6 | abstract function add_page_actions( $hook ); |
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| 7 | |||
| 8 | // Create a menu item for the page and returns the hook |
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| 9 | abstract function get_page_hook(); |
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| 10 | |||
| 11 | // Enqueue and localize page specific scripts |
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| 12 | abstract function page_admin_scripts(); |
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| 13 | |||
| 14 | // Render page specific HTML |
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| 15 | abstract function page_render(); |
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| 16 | |||
| 17 | /** |
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| 18 | * Should we block the page rendering because the site is in IDC? |
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| 19 | * @var bool |
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| 20 | */ |
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| 21 | static $block_page_rendering_for_idc; |
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| 22 | |||
| 23 | /** |
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| 24 | * Flag to know if we already checked the plan. |
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| 25 | * |
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| 26 | * @since 4.4.0 |
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| 27 | * |
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| 28 | * @var bool |
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| 29 | */ |
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| 30 | static $plan_checked = false; |
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| 31 | |||
| 32 | /** |
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| 33 | * Function called after admin_styles to load any additional needed styles. |
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| 34 | * |
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| 35 | * @since 4.3.0 |
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| 36 | */ |
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| 37 | function additional_styles() {} |
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| 38 | |||
| 39 | function __construct() { |
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| 49 | |||
| 50 | function add_actions() { |
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| 80 | |||
| 81 | function admin_head() { |
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| 96 | |||
| 97 | // Render the page with a common top and bottom part, and page specific content |
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| 98 | function render() { |
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| 106 | |||
| 107 | function admin_help() { |
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| 110 | |||
| 111 | function admin_page_load() { |
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| 115 | |||
| 116 | function admin_page_top() { |
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| 119 | |||
| 120 | function admin_page_bottom() { |
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| 123 | |||
| 124 | // Add page specific scripts and jetpack stats for all menu pages |
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| 125 | function admin_scripts() { |
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| 129 | |||
| 130 | // Enqueue the Jetpack admin stylesheet |
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| 131 | function admin_styles() { |
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| 138 | |||
| 139 | function is_wp_version_too_old() { |
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| 143 | |||
| 144 | /** |
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| 145 | * Checks the site plan and deactivates modules that were active but are no longer included in the plan. |
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| 146 | * |
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| 147 | * @since 4.4.0 |
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| 148 | * |
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| 149 | * @param $page |
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| 150 | * |
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| 151 | * @return bool|array |
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| 152 | */ |
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| 153 | function check_plan_deactivate_modules( $page ) { |
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| 218 | } |
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| 219 |
The PSR-2 coding standard requires that all properties in a class have their visibility explicitly declared. If you declare a property using
the property is implicitly global.
To learn more about the PSR-2, please see the PHP-FIG site on the PSR-2.