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 Post_Meta_Container 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 Post_Meta_Container, and based on these observations, apply Extract Interface, too.
1 | <?php |
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13 | class Post_Meta_Container extends Container { |
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14 | /** |
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15 | * ID of the post the container is working with |
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16 | * |
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17 | * @see init() |
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18 | * @var int |
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19 | */ |
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20 | protected $post_id; |
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21 | |||
22 | /** |
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23 | * List of default container settings |
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24 | * |
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25 | * @see init() |
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26 | * @var array |
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27 | */ |
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28 | public $settings = array( |
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29 | 'post_type' => array( 'post' ), |
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30 | 'panel_context' => 'normal', |
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31 | 'panel_priority' => 'high', |
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32 | 'show_on' => array( |
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33 | 'category' => null, |
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34 | 'template_names' => array(), |
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35 | 'not_in_template_names' => array(), |
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36 | 'post_formats' => array(), |
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37 | 'level_limit' => null, |
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38 | 'tax_term_id' => null, |
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39 | 'page_id' => null, |
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40 | 'parent_page_id' => null, |
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41 | 'post_path' => null, |
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42 | ), |
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43 | ); |
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44 | |||
45 | /** |
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46 | * Create a new container |
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47 | * |
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48 | * @param string $unique_id Unique id of the container |
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49 | * @param string $title title of the container |
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50 | * @param string $type Type of the container |
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51 | **/ |
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52 | View Code Duplication | public function __construct( $unique_id, $title, $type ) { |
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59 | |||
60 | /** |
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61 | * Create DataStore instance, set post ID to operate with (if such exists). |
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62 | * Bind attach() and save() to the appropriate WordPress actions. |
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63 | **/ |
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64 | public function init() { |
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83 | |||
84 | /** |
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85 | * Checks whether the current save request is valid |
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86 | * Possible errors are triggering save() for autosave requests |
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87 | * or performing post save outside of the post edit page (like Quick Edit) |
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88 | * |
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89 | * @param int $post_id ID of the post against which save() is ran |
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90 | * @return bool |
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91 | **/ |
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92 | public function is_valid_save( $post_id = 0 ) { |
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103 | |||
104 | /** |
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105 | * Perform save operation after successful is_valid_save() check. |
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106 | * The call is propagated to all fields in the container. |
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107 | * |
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108 | * @param int $post_id ID of the post against which save() is ran |
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109 | **/ |
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110 | View Code Duplication | public function save( $post_id = null ) { |
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124 | |||
125 | /** |
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126 | * Perform checks whether the container should be attached during the current request |
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127 | * |
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128 | * @return bool True if the container is allowed to be attached |
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129 | **/ |
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130 | public function is_valid_attach_for_request() { |
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171 | |||
172 | /** |
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173 | * Check container attachment rules against object id |
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174 | * |
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175 | * @param int $object_id |
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176 | * @return bool |
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177 | **/ |
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178 | public function is_valid_attach_for_object( $object_id = null ) { |
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203 | |||
204 | /** |
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205 | * Add meta box for each of the container post types |
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206 | **/ |
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207 | public function attach() { |
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223 | |||
224 | /** |
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225 | * Classes to add to the post meta box |
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226 | */ |
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227 | public function add_postbox_classes( $classes ) { |
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231 | |||
232 | /** |
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233 | * Output the container markup |
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234 | **/ |
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235 | public function render() { |
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238 | |||
239 | /** |
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240 | * Set the post ID the container will operate with. |
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241 | * |
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242 | * @param int $post_id |
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243 | **/ |
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244 | public function set_post_id( $post_id ) { |
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248 | |||
249 | /** |
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250 | * CONDITION TOOLS |
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251 | */ |
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252 | |||
253 | /** |
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254 | * Check a condition against all supported conditions |
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255 | * |
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256 | * @param string $condition |
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257 | * @param mixed $value |
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258 | * @param WP_Post $post |
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259 | * @return bool |
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260 | */ |
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261 | protected function is_condition_fullfilled( $condition, $value, $post ) { |
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323 | |||
324 | /** |
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325 | * Check if a post is of a given post format |
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326 | * |
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327 | * @param WP_Post $post |
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328 | * @param string $format |
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329 | * @return bool |
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330 | */ |
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331 | protected function condition_is_post_of_format( $post, $format ) { |
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343 | |||
344 | /** |
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345 | * Check if a post is on a specific level in it's hierarchy |
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346 | * |
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347 | * @param WP_Post $post |
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348 | * @param int $level |
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349 | * @return bool |
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350 | */ |
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351 | protected function condition_is_post_on_level( $post, $level ) { |
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356 | |||
357 | /** |
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358 | * Check if a post uses one of a given array of templates |
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359 | * |
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360 | * @param WP_Post $post |
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361 | * @param string|array<string> $templates |
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362 | * @return bool |
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363 | */ |
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364 | protected function condition_is_post_using_template( $post, $templates ) { |
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369 | |||
370 | /** |
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371 | * COMMON USAGE METHODS |
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372 | */ |
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373 | |||
374 | /** |
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375 | * Show the container only on particular page referenced by it's path. |
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376 | * |
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377 | * @param int|string $page page ID or page path |
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378 | * @return object $this |
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379 | **/ |
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380 | 4 | public function show_on_page( $page ) { |
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399 | |||
400 | /** |
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401 | * Show the container only on pages whose parent is referenced by $parent_page_path. |
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402 | * |
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403 | * @param string $parent_page_path |
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404 | * @return object $this |
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405 | **/ |
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406 | 1 | public function show_on_page_children( $parent_page_path ) { |
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419 | |||
420 | /** |
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421 | * Show the container only on posts from the specified category. |
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422 | * |
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423 | * @see show_on_taxonomy_term() |
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424 | * |
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425 | * @param string $category_slug |
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426 | * @return object $this |
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427 | **/ |
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428 | public function show_on_category( $category_slug ) { |
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433 | |||
434 | /** |
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435 | * Show the container only on pages whose template has filename $template_path. |
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436 | * |
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437 | * @param string|array $template_path |
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438 | * @return object $this |
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439 | **/ |
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440 | 2 | public function show_on_template( $template_path ) { |
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458 | |||
459 | /** |
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460 | * Hide the container from pages whose template has filename $template_path. |
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461 | * |
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462 | * @param string|array $template_path |
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463 | * @return object $this |
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464 | **/ |
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465 | public function hide_on_template( $template_path ) { |
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477 | |||
478 | /** |
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479 | * Show the container only on hierarchical posts of level $level. |
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480 | * Levels start from 1 (top level post) |
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481 | * |
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482 | * @param int $level |
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483 | * @return object $this |
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484 | **/ |
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485 | public function show_on_level( $level ) { |
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494 | |||
495 | /** |
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496 | * Show the container only on posts which have term $term_slug from the $taxonomy_slug taxonomy. |
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497 | * |
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498 | * @param string $taxonomy_slug |
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499 | * @param string $term_slug |
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500 | * @return object $this |
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501 | **/ |
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502 | public function show_on_taxonomy_term( $term_slug, $taxonomy_slug ) { |
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511 | |||
512 | /** |
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513 | * Show the container only on posts from the specified format. |
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514 | * Learn more about {@link http://codex.wordpress.org/Post_Formats Post Formats (Codex)} |
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515 | * |
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516 | * @param string|array $post_format Name of the format as listed on Codex |
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517 | * @return object $this |
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518 | **/ |
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519 | public function show_on_post_format( $post_format ) { |
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535 | |||
536 | /** |
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537 | * Show the container only on posts from the specified type(s). |
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538 | * |
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539 | * @param string|array $post_types |
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540 | * @return object $this |
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541 | **/ |
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542 | public function show_on_post_type( $post_types ) { |
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549 | |||
550 | /** |
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551 | * Sets the meta box container context |
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552 | * |
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553 | * @see https://codex.wordpress.org/Function_Reference/add_meta_box |
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554 | * @param string $context ('normal', 'advanced' or 'side') |
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555 | */ |
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556 | public function set_context( $context ) { |
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561 | |||
562 | /** |
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563 | * Sets the meta box container priority |
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564 | * |
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565 | * @see https://codex.wordpress.org/Function_Reference/add_meta_box |
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566 | * @param string $priority ('high', 'core', 'default' or 'low') |
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567 | */ |
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568 | public function set_priority( $priority ) { |
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573 | } |
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574 |