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 BlogPost 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 BlogPost, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 44 | class BlogPost extends Page |
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| 45 | { |
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| 46 | /** |
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| 47 | * Same as above, but for list of users that can be |
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| 48 | * given credit in the author field for blog posts |
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| 49 | * @var string|bool false or group code |
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| 50 | */ |
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| 51 | private static $restrict_authors_to_group = false; |
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| 52 | |||
| 53 | /** |
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| 54 | * {@inheritDoc} |
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| 55 | * @var string |
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| 56 | */ |
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| 57 | private static $table_name = 'BlogPost'; |
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| 58 | |||
| 59 | /** |
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| 60 | * @var array |
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| 61 | */ |
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| 62 | private static $db = array( |
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| 63 | 'PublishDate' => 'Datetime', |
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| 64 | 'AuthorNames' => 'Varchar(1024)', |
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| 65 | 'Summary' => 'HTMLText' |
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| 66 | ); |
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| 67 | |||
| 68 | /** |
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| 69 | * @var array |
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| 70 | */ |
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| 71 | private static $has_one = array( |
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| 72 | 'FeaturedImage' => Image::class |
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| 73 | ); |
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| 74 | |||
| 75 | /** |
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| 76 | * @var array |
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| 77 | */ |
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| 78 | private static $many_many = array( |
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| 79 | 'Categories' => BlogCategory::class, |
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| 80 | 'Tags' => BlogTag::class, |
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| 81 | 'Authors' => Member::class |
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| 82 | ); |
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| 83 | |||
| 84 | /** |
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| 85 | * @var array |
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| 86 | */ |
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| 87 | private static $defaults = array( |
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| 88 | 'ShowInMenus' => false, |
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| 89 | 'InheritSideBar' => true, |
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| 90 | 'ProvideComments' => true |
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| 91 | ); |
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| 92 | |||
| 93 | /** |
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| 94 | * @var array |
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| 95 | */ |
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| 96 | private static $extensions = array( |
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| 97 | BlogPostFilter::class |
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| 98 | ); |
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| 99 | |||
| 100 | /** |
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| 101 | * @var array |
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| 102 | */ |
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| 103 | private static $searchable_fields = array( |
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| 104 | 'Title' |
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| 105 | ); |
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| 106 | |||
| 107 | /** |
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| 108 | * @var array |
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| 109 | */ |
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| 110 | private static $summary_fields = array( |
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| 111 | 'Title' |
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| 112 | ); |
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| 113 | |||
| 114 | /** |
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| 115 | * @var array |
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| 116 | */ |
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| 117 | private static $casting = array( |
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| 118 | 'Excerpt' => 'HTMLText', |
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| 119 | 'Date' => 'DBDatetime' |
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| 120 | ); |
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| 121 | |||
| 122 | /** |
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| 123 | * @var array |
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| 124 | */ |
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| 125 | private static $allowed_children = array(); |
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| 126 | |||
| 127 | /** |
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| 128 | * The default sorting lists BlogPosts with an empty PublishDate at the top. |
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| 129 | * |
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| 130 | * @var string |
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| 131 | */ |
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| 132 | private static $default_sort = '"PublishDate" IS NULL DESC, "PublishDate" DESC'; |
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| 133 | |||
| 134 | /** |
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| 135 | * @var bool |
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| 136 | */ |
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| 137 | private static $can_be_root = false; |
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| 138 | |||
| 139 | /** |
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| 140 | * This will display or hide the current class from the SiteTree. This variable can be |
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| 141 | * configured using YAML. |
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| 142 | * |
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| 143 | * @var bool |
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| 144 | */ |
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| 145 | private static $show_in_sitetree = false; |
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| 146 | |||
| 147 | /** |
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| 148 | * Determine the role of the given member. |
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| 149 | * |
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| 150 | * Call be called via template to determine the current user. |
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| 151 | * |
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| 152 | * @example "Hello $RoleOf($CurrentMember.ID)" |
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| 153 | * |
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| 154 | * @param null|int|Member $member |
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| 155 | * |
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| 156 | * @return null|string |
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| 157 | */ |
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| 158 | public function RoleOf($member = null) |
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| 178 | |||
| 179 | /** |
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| 180 | * Determine if the given member is an author of this post. |
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| 181 | * |
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| 182 | * @param null|Member $member |
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| 183 | * |
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| 184 | * @return bool |
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| 185 | */ |
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| 186 | View Code Duplication | public function isAuthor($member = null) |
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| 200 | |||
| 201 | /** |
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| 202 | * {@inheritdoc} |
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| 203 | */ |
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| 204 | public function getCMSFields() |
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| 326 | |||
| 327 | /** |
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| 328 | * Gets the list of author candidates to be assigned as authors of this blog post. |
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| 329 | * |
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| 330 | * @return SS_List |
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| 331 | */ |
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| 332 | public function getCandidateAuthors() |
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| 342 | |||
| 343 | /** |
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| 344 | * Determine if this user can edit the authors list. |
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| 345 | * |
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| 346 | * @param null|int|Member $member |
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| 347 | * |
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| 348 | * @return bool |
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| 349 | */ |
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| 350 | public function canEditAuthors($member = null) |
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| 374 | |||
| 375 | /** |
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| 376 | * @param null|int|Member $member |
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| 377 | * |
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| 378 | * @return null|Member |
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| 379 | */ |
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| 380 | View Code Duplication | protected function getMember($member = null) |
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| 392 | |||
| 393 | /** |
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| 394 | * Determine whether user can create new categories. |
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| 395 | * |
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| 396 | * @param null|int|Member $member |
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| 397 | * |
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| 398 | * @return bool |
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| 399 | */ |
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| 400 | View Code Duplication | public function canCreateCategories($member = null) |
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| 416 | |||
| 417 | /** |
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| 418 | * Determine whether user can create new tags. |
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| 419 | * |
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| 420 | * @param null|int|Member $member |
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| 421 | * |
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| 422 | * @return bool |
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| 423 | */ |
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| 424 | View Code Duplication | public function canCreateTags($member = null) |
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| 444 | |||
| 445 | /** |
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| 446 | * {@inheritdoc} |
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| 447 | * |
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| 448 | * Update the PublishDate to now if the BlogPost would otherwise be published without a date. |
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| 449 | */ |
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| 450 | public function onBeforePublish() |
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| 462 | |||
| 463 | /** |
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| 464 | * {@inheritdoc} |
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| 465 | * |
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| 466 | * Sets blog relationship on all categories and tags assigned to this post. |
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| 467 | */ |
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| 468 | public function onAfterWrite() |
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| 488 | |||
| 489 | /** |
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| 490 | * {@inheritdoc} |
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| 491 | */ |
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| 492 | public function canView($member = null) |
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| 514 | |||
| 515 | /** |
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| 516 | * {@inheritdoc} |
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| 517 | */ |
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| 518 | public function canPublish($member = null) |
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| 550 | |||
| 551 | /** |
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| 552 | * {@inheritdoc} |
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| 553 | */ |
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| 554 | public function canEdit($member = null) |
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| 578 | |||
| 579 | /** |
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| 580 | * Returns the post excerpt. |
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| 581 | * |
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| 582 | * @param int $wordsToDisplay |
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| 583 | * |
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| 584 | * @return string |
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| 585 | */ |
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| 586 | public function Excerpt($wordsToDisplay = 30) |
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| 593 | |||
| 594 | /** |
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| 595 | * Returns a monthly archive link for the current blog post. |
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| 596 | * |
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| 597 | * @param string $type |
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| 598 | * |
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| 599 | * @return string |
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| 600 | */ |
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| 601 | public function getMonthlyArchiveLink($type = 'day') |
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| 623 | |||
| 624 | /** |
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| 625 | * Returns a yearly archive link for the current blog post. |
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| 626 | * |
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| 627 | * @return string |
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| 628 | */ |
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| 629 | public function getYearlyArchiveLink() |
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| 638 | |||
| 639 | /** |
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| 640 | * Resolves static and dynamic authors linked to this post. |
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| 641 | * |
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| 642 | * @return ArrayList |
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| 643 | */ |
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| 644 | public function getCredits() |
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| 653 | |||
| 654 | /** |
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| 655 | * Resolves dynamic authors linked to this post. |
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| 656 | * |
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| 657 | * @return ArrayList |
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| 658 | */ |
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| 659 | protected function getDynamicCredits() |
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| 685 | |||
| 686 | /** |
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| 687 | * Resolves static authors linked to this post. |
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| 688 | * |
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| 689 | * @return ArrayList |
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| 690 | */ |
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| 691 | protected function getStaticCredits() |
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| 707 | |||
| 708 | /** |
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| 709 | * Sets the label for BlogPost.Title to 'Post Title' (Rather than 'Page name'). |
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| 710 | * |
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| 711 | * @param bool $includeRelations |
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| 712 | * |
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| 713 | * @return array |
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| 714 | */ |
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| 715 | public function fieldLabels($includeRelations = true) |
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| 723 | |||
| 724 | /** |
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| 725 | * Proxy method for displaying the publish date in rss feeds. |
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| 726 | * @see https://github.com/silverstripe/silverstripe-blog/issues/394 |
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| 727 | * |
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| 728 | * @return string|null |
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| 729 | */ |
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| 730 | public function getDate() |
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| 734 | |||
| 735 | /** |
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| 736 | * {@inheritdoc} |
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| 737 | */ |
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| 738 | protected function onBeforeWrite() |
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| 746 | } |
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| 747 |
This check marks private properties in classes that are never used. Those properties can be removed.