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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| 40 | class BlogPost extends Page |
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| 41 | { |
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| 42 | /** |
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| 43 | * Same as above, but for list of users that can be |
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| 44 | * given credit in the author field for blog posts |
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| 45 | * @var string|bool false or group code |
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| 46 | */ |
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| 47 | private static $restrict_authors_to_group = false; |
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| 48 | |||
| 49 | /** |
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| 50 | * {@inheritDoc} |
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| 51 | * @var string |
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| 52 | */ |
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| 53 | private static $table_name = 'BlogPost'; |
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| 54 | |||
| 55 | /** |
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| 56 | * @var array |
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| 57 | */ |
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| 58 | private static $db = array( |
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| 59 | 'PublishDate' => 'Datetime', |
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| 60 | 'AuthorNames' => 'Varchar(1024)', |
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| 61 | 'Summary' => 'HTMLText' |
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| 62 | ); |
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| 63 | |||
| 64 | /** |
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| 65 | * @var array |
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| 66 | */ |
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| 67 | private static $has_one = array( |
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| 68 | 'FeaturedImage' => 'SilverStripe\\Assets\\Image' |
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| 69 | ); |
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| 70 | |||
| 71 | /** |
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| 72 | * @var array |
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| 73 | */ |
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| 74 | private static $many_many = array( |
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| 75 | 'Categories' => 'SilverStripe\\Blog\\Model\\BlogCategory', |
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| 76 | 'Tags' => 'SilverStripe\\Blog\\Model\\BlogTag', |
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| 77 | 'Authors' => Member::class |
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| 78 | ); |
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| 79 | |||
| 80 | /** |
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| 81 | * @var array |
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| 82 | */ |
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| 83 | private static $defaults = array( |
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| 84 | 'ShowInMenus' => false, |
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| 85 | 'InheritSideBar' => true, |
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| 86 | 'ProvideComments' => true |
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| 87 | ); |
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| 88 | |||
| 89 | /** |
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| 90 | * @var array |
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| 91 | */ |
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| 92 | private static $extensions = array( |
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| 93 | 'SilverStripe\\Blog\\Model\\BlogPostFilter' |
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| 94 | ); |
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| 95 | |||
| 96 | /** |
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| 97 | * @var array |
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| 98 | */ |
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| 99 | private static $searchable_fields = array( |
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| 100 | 'Title' |
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| 101 | ); |
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| 102 | |||
| 103 | /** |
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| 104 | * @var array |
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| 105 | */ |
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| 106 | private static $summary_fields = array( |
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| 107 | 'Title' |
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| 108 | ); |
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| 109 | |||
| 110 | /** |
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| 111 | * @var array |
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| 112 | */ |
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| 113 | private static $casting = array( |
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| 114 | 'Excerpt' => 'HTMLText', |
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| 115 | 'Date' => 'DBDatetime' |
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| 116 | ); |
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| 117 | |||
| 118 | /** |
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| 119 | * @var array |
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| 120 | */ |
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| 121 | private static $allowed_children = array(); |
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| 122 | |||
| 123 | /** |
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| 124 | * The default sorting lists BlogPosts with an empty PublishDate at the top. |
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| 125 | * |
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| 126 | * @var string |
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| 127 | */ |
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| 128 | private static $default_sort = '"PublishDate" IS NULL DESC, "PublishDate" DESC'; |
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| 129 | |||
| 130 | /** |
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| 131 | * @var bool |
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| 132 | */ |
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| 133 | private static $can_be_root = false; |
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| 134 | |||
| 135 | /** |
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| 136 | * This will display or hide the current class from the SiteTree. This variable can be |
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| 137 | * configured using YAML. |
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| 138 | * |
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| 139 | * @var bool |
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| 140 | */ |
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| 141 | private static $show_in_sitetree = false; |
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| 142 | |||
| 143 | /** |
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| 144 | * Determine the role of the given member. |
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| 145 | * |
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| 146 | * Call be called via template to determine the current user. |
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| 147 | * |
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| 148 | * @example "Hello $RoleOf($CurrentMember.ID)" |
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| 149 | * |
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| 150 | * @param null|int|Member $member |
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| 151 | * |
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| 152 | * @return null|string |
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| 153 | */ |
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| 154 | public function RoleOf($member = null) |
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| 174 | |||
| 175 | /** |
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| 176 | * Determine if the given member is an author of this post. |
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| 177 | * |
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| 178 | * @param null|Member $member |
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| 179 | * |
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| 180 | * @return bool |
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| 181 | */ |
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| 182 | View Code Duplication | public function isAuthor($member = null) |
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| 196 | |||
| 197 | /** |
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| 198 | * {@inheritdoc} |
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| 199 | */ |
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| 200 | public function getCMSFields() |
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| 322 | |||
| 323 | /** |
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| 324 | * Gets the list of author candidates to be assigned as authors of this blog post. |
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| 325 | * |
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| 326 | * @return SS_List |
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| 327 | */ |
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| 328 | public function getCandidateAuthors() |
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| 338 | |||
| 339 | /** |
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| 340 | * Determine if this user can edit the authors list. |
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| 341 | * |
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| 342 | * @param null|int|Member $member |
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| 343 | * |
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| 344 | * @return bool |
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| 345 | */ |
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| 346 | public function canEditAuthors($member = null) |
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| 370 | |||
| 371 | /** |
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| 372 | * @param null|int|Member $member |
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| 373 | * |
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| 374 | * @return null|Member |
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| 375 | */ |
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| 376 | View Code Duplication | protected function getMember($member = null) |
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| 388 | |||
| 389 | /** |
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| 390 | * Determine whether user can create new categories. |
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| 391 | * |
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| 392 | * @param null|int|Member $member |
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| 393 | * |
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| 394 | * @return bool |
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| 395 | */ |
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| 396 | View Code Duplication | public function canCreateCategories($member = null) |
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| 412 | |||
| 413 | /** |
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| 414 | * Determine whether user can create new tags. |
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| 415 | * |
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| 416 | * @param null|int|Member $member |
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| 417 | * |
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| 418 | * @return bool |
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| 419 | */ |
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| 420 | View Code Duplication | public function canCreateTags($member = null) |
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| 440 | |||
| 441 | /** |
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| 442 | * {@inheritdoc} |
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| 443 | * |
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| 444 | * Update the PublishDate to now if the BlogPost would otherwise be published without a date. |
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| 445 | */ |
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| 446 | public function onBeforePublish() |
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| 458 | |||
| 459 | /** |
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| 460 | * {@inheritdoc} |
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| 461 | * |
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| 462 | * Sets blog relationship on all categories and tags assigned to this post. |
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| 463 | */ |
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| 464 | public function onAfterWrite() |
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| 484 | |||
| 485 | /** |
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| 486 | * {@inheritdoc} |
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| 487 | */ |
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| 488 | public function canView($member = null) |
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| 510 | |||
| 511 | /** |
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| 512 | * {@inheritdoc} |
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| 513 | */ |
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| 514 | public function canPublish($member = null) |
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| 546 | |||
| 547 | /** |
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| 548 | * {@inheritdoc} |
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| 549 | */ |
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| 550 | public function canEdit($member = null) |
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| 574 | |||
| 575 | /** |
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| 576 | * Returns the post excerpt. |
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| 577 | * |
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| 578 | * @param int $wordsToDisplay |
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| 579 | * |
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| 580 | * @return string |
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| 581 | */ |
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| 582 | public function Excerpt($wordsToDisplay = 30) |
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| 589 | |||
| 590 | /** |
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| 591 | * Returns a monthly archive link for the current blog post. |
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| 592 | * |
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| 593 | * @param string $type |
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| 594 | * |
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| 595 | * @return string |
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| 596 | */ |
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| 597 | public function getMonthlyArchiveLink($type = 'day') |
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| 619 | |||
| 620 | /** |
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| 621 | * Returns a yearly archive link for the current blog post. |
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| 622 | * |
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| 623 | * @return string |
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| 624 | */ |
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| 625 | public function getYearlyArchiveLink() |
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| 634 | |||
| 635 | /** |
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| 636 | * Resolves static and dynamic authors linked to this post. |
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| 637 | * |
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| 638 | * @return ArrayList |
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| 639 | */ |
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| 640 | public function getCredits() |
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| 649 | |||
| 650 | /** |
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| 651 | * Resolves dynamic authors linked to this post. |
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| 652 | * |
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| 653 | * @return ArrayList |
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| 654 | */ |
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| 655 | protected function getDynamicCredits() |
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| 681 | |||
| 682 | /** |
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| 683 | * Resolves static authors linked to this post. |
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| 684 | * |
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| 685 | * @return ArrayList |
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| 686 | */ |
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| 687 | protected function getStaticCredits() |
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| 703 | |||
| 704 | /** |
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| 705 | * Sets the label for BlogPost.Title to 'Post Title' (Rather than 'Page name'). |
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| 706 | * |
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| 707 | * @param bool $includeRelations |
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| 708 | * |
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| 709 | * @return array |
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| 710 | */ |
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| 711 | public function fieldLabels($includeRelations = true) |
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| 719 | |||
| 720 | /** |
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| 721 | * Proxy method for displaying the publish date in rss feeds. |
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| 722 | * @see https://github.com/silverstripe/silverstripe-blog/issues/394 |
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| 723 | * |
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| 724 | * @return string|null |
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| 725 | */ |
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| 726 | public function getDate() |
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| 730 | |||
| 731 | /** |
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| 732 | * {@inheritdoc} |
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| 733 | */ |
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| 734 | protected function onBeforeWrite() |
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| 742 | } |
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| 743 |
This check marks private properties in classes that are never used. Those properties can be removed.