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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45 | class BlogPost extends Page |
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46 | { |
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47 | /** |
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48 | * Same as above, but for list of users that can be |
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49 | * given credit in the author field for blog posts |
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50 | * @var string|bool false or group code |
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51 | */ |
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52 | private static $restrict_authors_to_group = false; |
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53 | |||
54 | /** |
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55 | * {@inheritDoc} |
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56 | * @var string |
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57 | */ |
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58 | private static $table_name = 'BlogPost'; |
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59 | |||
60 | /** |
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61 | * @var array |
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62 | */ |
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63 | private static $db = [ |
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64 | 'PublishDate' => 'Datetime', |
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65 | 'AuthorNames' => 'Varchar(1024)', |
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66 | 'Summary' => 'HTMLText' |
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67 | ]; |
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68 | |||
69 | /** |
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70 | * @var array |
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71 | */ |
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72 | private static $has_one = [ |
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73 | 'FeaturedImage' => Image::class |
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74 | ]; |
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75 | |||
76 | /** |
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77 | * @var array |
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78 | */ |
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79 | private static $owns = [ |
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80 | 'FeaturedImage', |
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81 | ]; |
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82 | |||
83 | /** |
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84 | * @var array |
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85 | */ |
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86 | private static $many_many = [ |
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87 | 'Categories' => BlogCategory::class, |
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88 | 'Tags' => BlogTag::class, |
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89 | 'Authors' => Member::class |
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90 | ]; |
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91 | |||
92 | /** |
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93 | * @var array |
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94 | */ |
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95 | private static $defaults = [ |
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96 | 'ShowInMenus' => false, |
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97 | 'InheritSideBar' => true, |
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98 | 'ProvideComments' => true |
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99 | ]; |
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100 | |||
101 | /** |
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102 | * @var array |
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103 | */ |
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104 | private static $extensions = [ |
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105 | BlogPostFilter::class |
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106 | ]; |
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107 | |||
108 | /** |
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109 | * @var array |
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110 | */ |
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111 | private static $searchable_fields = [ |
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112 | 'Title' |
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113 | ]; |
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114 | |||
115 | /** |
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116 | * @var array |
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117 | */ |
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118 | private static $summary_fields = [ |
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119 | 'Title' |
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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 $casting = [ |
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126 | 'Excerpt' => 'HTMLText', |
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127 | 'Date' => 'DBDatetime' |
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128 | ]; |
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129 | |||
130 | /** |
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131 | * @var array |
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132 | */ |
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133 | private static $allowed_children = []; |
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134 | |||
135 | /** |
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136 | * The default sorting lists BlogPosts with an empty PublishDate at the top. |
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137 | * |
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138 | * @var string |
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139 | */ |
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140 | private static $default_sort = '"PublishDate" IS NULL DESC, "PublishDate" DESC'; |
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141 | |||
142 | /** |
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143 | * @var bool |
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144 | */ |
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145 | private static $can_be_root = false; |
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146 | |||
147 | /** |
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148 | * This will display or hide the current class from the SiteTree. This variable can be |
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149 | * configured using YAML. |
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150 | * |
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151 | * @var bool |
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152 | */ |
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153 | private static $show_in_sitetree = false; |
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154 | |||
155 | /** |
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156 | * Determine the role of the given member. |
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157 | * |
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158 | * Call be called via template to determine the current user. |
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159 | * |
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160 | * @example "Hello $RoleOf($CurrentMember.ID)" |
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161 | * |
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162 | * @param null|int|Member $member |
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163 | * |
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164 | * @return null|string |
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165 | */ |
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166 | public function RoleOf($member = null) |
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186 | |||
187 | /** |
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188 | * Determine if the given member is an author of this post. |
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189 | * |
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190 | * @param null|Member $member |
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191 | * |
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192 | * @return bool |
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193 | */ |
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194 | View Code Duplication | public function isAuthor($member = null) |
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208 | |||
209 | /** |
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210 | * {@inheritdoc} |
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211 | */ |
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212 | public function getCMSFields() |
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335 | |||
336 | /** |
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337 | * Gets the list of author candidates to be assigned as authors of this blog post. |
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338 | * |
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339 | * @return SS_List |
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340 | */ |
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341 | public function getCandidateAuthors() |
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351 | |||
352 | /** |
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353 | * Determine if this user can edit the authors list. |
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354 | * |
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355 | * @param null|int|Member $member |
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356 | * |
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357 | * @return bool |
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358 | */ |
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359 | public function canEditAuthors($member = null) |
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383 | |||
384 | /** |
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385 | * @param null|int|Member $member |
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386 | * |
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387 | * @return null|Member |
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388 | */ |
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389 | View Code Duplication | protected function getMember($member = null) |
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401 | |||
402 | /** |
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403 | * Determine whether user can create new categories. |
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404 | * |
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405 | * @param null|int|Member $member |
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406 | * |
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407 | * @return bool |
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408 | */ |
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409 | View Code Duplication | public function canCreateCategories($member = null) |
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425 | |||
426 | /** |
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427 | * Determine whether user can create new tags. |
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428 | * |
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429 | * @param null|int|Member $member |
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430 | * |
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431 | * @return bool |
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432 | */ |
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433 | View Code Duplication | public function canCreateTags($member = null) |
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453 | |||
454 | /** |
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455 | * {@inheritdoc} |
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456 | * |
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457 | * Update the PublishDate to now if the BlogPost would otherwise be published without a date. |
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458 | */ |
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459 | public function onBeforePublish() |
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471 | |||
472 | /** |
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473 | * {@inheritdoc} |
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474 | * |
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475 | * Sets blog relationship on all categories and tags assigned to this post. |
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476 | */ |
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477 | public function onAfterWrite() |
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497 | |||
498 | /** |
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499 | * {@inheritdoc} |
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500 | */ |
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501 | public function canView($member = null) |
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528 | |||
529 | /** |
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530 | * {@inheritdoc} |
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531 | */ |
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532 | public function canPublish($member = null) |
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564 | |||
565 | /** |
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566 | * {@inheritdoc} |
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567 | */ |
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568 | public function canEdit($member = null) |
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592 | |||
593 | /** |
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594 | * Returns the post excerpt. |
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595 | * |
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596 | * @param int $wordsToDisplay |
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597 | * |
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598 | * @return string |
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599 | */ |
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600 | public function Excerpt($wordsToDisplay = 30) |
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607 | |||
608 | /** |
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609 | * Returns a monthly archive link for the current blog post. |
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610 | * |
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611 | * @param string $type |
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612 | * |
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613 | * @return string |
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614 | */ |
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615 | public function getMonthlyArchiveLink($type = 'day') |
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637 | |||
638 | /** |
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639 | * Returns a yearly archive link for the current blog post. |
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640 | * |
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641 | * @return string |
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642 | */ |
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643 | public function getYearlyArchiveLink() |
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652 | |||
653 | /** |
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654 | * Resolves static and dynamic authors linked to this post. |
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655 | * |
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656 | * @return ArrayList |
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657 | */ |
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658 | public function getCredits() |
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667 | |||
668 | /** |
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669 | * Resolves dynamic authors linked to this post. |
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670 | * |
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671 | * @return ArrayList |
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672 | */ |
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673 | protected function getDynamicCredits() |
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699 | |||
700 | /** |
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701 | * Resolves static authors linked to this post. |
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702 | * |
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703 | * @return ArrayList |
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704 | */ |
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705 | protected function getStaticCredits() |
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721 | |||
722 | /** |
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723 | * Checks to see if User Profiles has been disabled via config |
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724 | * |
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725 | * @return bool |
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726 | */ |
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727 | public function getProfilesDisabled() |
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731 | |||
732 | /** |
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733 | * Sets the label for BlogPost.Title to 'Post Title' (Rather than 'Page name'). |
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734 | * |
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735 | * @param bool $includeRelations |
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736 | * |
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737 | * @return array |
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738 | */ |
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739 | public function fieldLabels($includeRelations = true) |
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747 | |||
748 | /** |
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749 | * Proxy method for displaying the publish date in rss feeds. |
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750 | * @see https://github.com/silverstripe/silverstripe-blog/issues/394 |
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751 | * |
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752 | * @return string|null |
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753 | */ |
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754 | public function getDate() |
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761 | |||
762 | /** |
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763 | * {@inheritdoc} |
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764 | */ |
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765 | protected function onBeforeWrite() |
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773 | } |
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774 |
This check marks private properties in classes that are never used. Those properties can be removed.