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 Object 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 Object, and based on these observations, apply Extract Interface, too.
1 | <?php |
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32 | class Object |
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33 | { |
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34 | const TYPE_ACTIVITY = 'activity'; |
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35 | const TYPE_AGENT = 'agent'; |
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36 | const TYPE_GROUP = 'group'; |
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37 | const TYPE_STATEMENT_REFERENCE = 'statement_reference'; |
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38 | const TYPE_SUB_STATEMENT = 'sub_statement'; |
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39 | |||
40 | public $identifier; |
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41 | |||
42 | /** |
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43 | * @var string |
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44 | */ |
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45 | public $type; |
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46 | |||
47 | /** |
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48 | * @var string|null |
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49 | */ |
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50 | public $activityId; |
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51 | |||
52 | /** |
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53 | * @var bool|null |
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54 | */ |
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55 | public $hasActivityDefinition; |
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56 | |||
57 | /** |
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58 | * @var bool|null |
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59 | */ |
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60 | public $hasActivityName; |
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61 | |||
62 | /** |
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63 | * @var array|null |
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64 | */ |
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65 | public $activityName; |
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66 | |||
67 | /** |
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68 | * @var bool|null |
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69 | */ |
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70 | public $hasActivityDescription; |
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71 | |||
72 | /** |
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73 | * @var array|null |
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74 | */ |
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75 | public $activityDescription; |
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76 | |||
77 | /** |
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78 | * @var string|null |
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79 | */ |
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80 | public $activityType; |
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81 | |||
82 | /** |
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83 | * @var string|null |
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84 | */ |
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85 | public $activityMoreInfo; |
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86 | |||
87 | /** |
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88 | * @var Extensions|null |
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89 | */ |
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90 | public $activityExtensions; |
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91 | |||
92 | /** |
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93 | * @var string|null |
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94 | */ |
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95 | public $mbox; |
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96 | |||
97 | /** |
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98 | * @var string|null |
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99 | */ |
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100 | public $mboxSha1Sum; |
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101 | |||
102 | /** |
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103 | * @var string|null |
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104 | */ |
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105 | public $openId; |
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106 | |||
107 | /** |
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108 | * @var string|null |
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109 | */ |
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110 | public $accountName; |
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111 | |||
112 | /** |
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113 | * @var string|null |
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114 | */ |
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115 | public $accountHomePage; |
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116 | |||
117 | /** |
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118 | * @var string|null |
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119 | */ |
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120 | public $name; |
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121 | |||
122 | /** |
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123 | * @var Object[]|null |
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124 | */ |
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125 | public $members; |
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126 | |||
127 | /** |
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128 | * @var Object|null |
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129 | */ |
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130 | public $group; |
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131 | |||
132 | /** |
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133 | * @var string|null |
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134 | */ |
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135 | public $referencedStatementId; |
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136 | |||
137 | /** |
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138 | * @var Object|null |
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139 | */ |
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140 | public $actor; |
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141 | |||
142 | /** |
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143 | * @var Verb|null |
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144 | */ |
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145 | public $verb; |
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146 | |||
147 | /** |
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148 | * @var Object|null |
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149 | */ |
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150 | public $object; |
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151 | |||
152 | /** |
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153 | * @var Result|null |
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154 | */ |
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155 | public $result; |
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156 | |||
157 | /** |
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158 | * @var Context|null |
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159 | */ |
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160 | public $context; |
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161 | |||
162 | /** |
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163 | * @var Statement|null |
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164 | */ |
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165 | public $parentContext; |
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166 | |||
167 | /** |
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168 | * @var Statement|null |
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169 | */ |
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170 | public $groupingContext; |
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171 | |||
172 | /** |
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173 | * @var Statement|null |
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174 | */ |
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175 | public $categoryContext; |
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176 | |||
177 | /** |
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178 | * @var Statement|null |
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179 | */ |
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180 | public $otherContext; |
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181 | |||
182 | public static function fromModel(ObjectModel $model) |
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202 | |||
203 | public function getModel() |
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219 | |||
220 | private static function fromActivity(Activity $model) |
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267 | |||
268 | private static function fromActor(Actor $model) |
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298 | |||
299 | private static function fromSubStatement(SubStatement $model) |
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309 | |||
310 | private function getActivityModel() |
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346 | |||
347 | View Code Duplication | private function getActorModel() |
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373 | |||
374 | private function getSubStatementModel() |
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387 | } |
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388 |
Let’s assume that you have a directory layout like this:
and let’s assume the following content of
Bar.php
:If both files
OtherDir/Foo.php
andSomeDir/Foo.php
are loaded in the same runtime, you will see a PHP error such as the following:PHP Fatal error: Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.php
However, as
OtherDir/Foo.php
does not necessarily have to be loaded and the error is only triggered if it is loaded beforeOtherDir/Bar.php
, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias: