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:
| 1 | <?php  | 
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| 10 | class EditableCustomRule extends DataObject { | 
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| 11 | |||
| 12 | private static $condition_options = array(  | 
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| 13 | "IsBlank" => "Is blank",  | 
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| 14 | "IsNotBlank" => "Is not blank",  | 
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| 15 | "HasValue" => "Equals",  | 
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| 16 | "ValueNot" => "Doesn't equal",  | 
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| 17 | "ValueLessThan" => "Less than",  | 
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| 18 | "ValueLessThanEqual" => "Less than or equal",  | 
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| 19 | "ValueGreaterThan" => "Greater than",  | 
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| 20 | "ValueGreaterThanEqual" => "Greater than or equal"  | 
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| 21 | );  | 
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| 22 | |||
| 23 | private static $db = array(  | 
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| 24 | 		'Display' => 'Enum("Show,Hide")', | 
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| 25 | 		'ConditionOption' => 'Enum("IsBlank,IsNotBlank,HasValue,ValueNot,ValueLessThan,ValueLessThanEqual,ValueGreaterThan,ValueGreaterThanEqual")', | 
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| 26 | 'FieldValue' => 'Varchar'  | 
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| 27 | );  | 
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| 28 | |||
| 29 | private static $has_one = array(  | 
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| 30 | 'Parent' => 'EditableFormField',  | 
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| 31 | 'ConditionField' => 'EditableFormField'  | 
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| 32 | );  | 
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| 33 | |||
| 34 | /**  | 
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| 35 | * Built in extensions required  | 
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| 36 | *  | 
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| 37 | * @config  | 
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| 38 | * @var array  | 
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| 39 | */  | 
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| 40 | private static $extensions = array(  | 
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| 41 | 		"Versioned('Stage', 'Live')" | 
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| 42 | );  | 
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| 43 | |||
| 44 | /**  | 
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| 45 | * Publish this custom rule to the live site  | 
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| 46 | *  | 
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| 47 | 	 * Wrapper for the {@link Versioned} publish function | 
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| 48 | */  | 
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| 49 | 	public function doPublish($fromStage, $toStage, $createNewVersion = false) { | 
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| 52 | |||
| 53 | /**  | 
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| 54 | * Delete this custom rule from a given stage  | 
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| 55 | *  | 
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| 56 | 	 * Wrapper for the {@link Versioned} deleteFromStage function | 
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| 57 | */  | 
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| 58 | 	public function doDeleteFromStage($stage) { | 
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| 61 | |||
| 62 | |||
| 63 | /**  | 
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| 64 | * @param Member $member  | 
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| 65 | * @return bool  | 
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| 66 | */  | 
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| 67 | 	public function canDelete($member = null) { | 
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| 70 | |||
| 71 | /**  | 
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| 72 | * @param Member $member  | 
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| 73 | * @return bool  | 
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| 74 | */  | 
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| 75 | 	public function canEdit($member = null) { | 
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| 78 | |||
| 79 | /**  | 
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| 80 | * @param Member $member  | 
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| 81 | * @return bool  | 
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| 82 | */  | 
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| 83 | 	public function canView($member = null) { | 
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| 86 | |||
| 87 | /**  | 
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| 88 | * Return whether a user can create an object of this type  | 
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| 89 | *  | 
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| 90 | * @param Member $member  | 
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| 91 | * @param array $context Virtual parameter to allow context to be passed in to check  | 
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| 92 | * @return bool  | 
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| 93 | */  | 
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| 94 | View Code Duplication | 	public function canCreate($member = null) { | 
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| 104 | |||
| 105 | /**  | 
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| 106 | * Helper method to check the parent for this object  | 
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| 107 | *  | 
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| 108 | * @param array $args List of arguments passed to canCreate  | 
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| 109 | * @return DataObject Some parent dataobject to inherit permissions from  | 
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| 110 | */  | 
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| 111 | View Code Duplication |     protected function getCanCreateContext($args) { | 
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| 124 | |||
| 125 | /**  | 
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| 126 | * @param Member $member  | 
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| 127 | * @return bool  | 
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| 128 | */  | 
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| 129 |     public function canPublish($member = null) { | 
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| 132 | |||
| 133 | /**  | 
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| 134 | * @param Member $member  | 
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| 135 | * @return bool  | 
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| 136 | */  | 
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| 137 |     public function canUnpublish($member = null) { | 
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| 140 | }  | 
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| 141 | 
You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.