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 ClassInfo 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 ClassInfo, and based on these observations, apply Extract Interface, too.
1 | <?php |
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21 | class ClassInfo |
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22 | { |
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23 | |||
24 | /** |
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25 | * Wrapper for classes getter. |
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26 | * |
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27 | * @return array |
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28 | */ |
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29 | public static function allClasses() |
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33 | |||
34 | /** |
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35 | * Returns true if a class or interface name exists. |
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36 | * |
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37 | * @param string $class |
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38 | * @return bool |
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39 | */ |
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40 | public static function exists($class) |
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44 | |||
45 | /** |
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46 | * Cache for {@link hasTable()} |
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47 | * |
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48 | * @internal |
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49 | * @var array |
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50 | */ |
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51 | private static $_cache_all_tables = array(); |
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52 | |||
53 | /** |
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54 | * @internal |
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55 | * @var array Cache for {@link ancestry()}. |
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56 | */ |
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57 | private static $_cache_ancestry = array(); |
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58 | |||
59 | /** |
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60 | * Cache for parse_class_spec |
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61 | * |
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62 | * @internal |
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63 | * @var array |
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64 | */ |
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65 | private static $_cache_parse = []; |
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66 | |||
67 | /** |
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68 | * @todo Move this to SS_Database or DB |
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69 | * |
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70 | * @param string $tableName |
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71 | * @return bool |
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72 | */ |
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73 | public static function hasTable($tableName) |
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81 | |||
82 | public static function reset_db_cache() |
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87 | |||
88 | /** |
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89 | * Returns the manifest of all classes which are present in the database. |
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90 | * |
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91 | * @param string $class Class name to check enum values for ClassName field |
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92 | * @param boolean $includeUnbacked Flag indicating whether or not to include |
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93 | * types that don't exist as implemented classes. By default these are excluded. |
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94 | * @return array List of subclasses |
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95 | */ |
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96 | public static function getValidSubClasses($class = 'SilverStripe\\CMS\\Model\\SiteTree', $includeUnbacked = false) |
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111 | |||
112 | /** |
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113 | * Returns an array of the current class and all its ancestors and children |
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114 | * which require a DB table. |
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115 | * |
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116 | * @todo Move this into {@see DataObjectSchema} |
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117 | * |
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118 | * @param string|object $nameOrObject Class or object instance |
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119 | * @return array |
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120 | */ |
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121 | public static function dataClassesFor($nameOrObject) |
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144 | |||
145 | /** |
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146 | * @deprecated 4.0..5.0 |
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147 | */ |
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148 | public static function baseDataClass($class) |
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153 | |||
154 | /** |
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155 | * Returns a list of classes that inherit from the given class. |
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156 | * The resulting array includes the base class passed |
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157 | * through the $class parameter as the first array value. |
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158 | * |
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159 | * Example usage: |
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160 | * <code> |
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161 | * ClassInfo::subclassesFor('BaseClass'); |
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162 | * array( |
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163 | * 'BaseClass' => 'BaseClass', |
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164 | * 'ChildClass' => 'ChildClass', |
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165 | * 'GrandChildClass' => 'GrandChildClass' |
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166 | * ) |
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167 | * </code> |
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168 | * |
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169 | * @param string|object $nameOrObject The classname or object |
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170 | * @return array Names of all subclasses as an associative array. |
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171 | */ |
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172 | public static function subclassesFor($nameOrObject) |
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189 | |||
190 | /** |
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191 | * Convert a class name in any case and return it as it was defined in PHP |
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192 | * |
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193 | * eg: self::class_name('dataobJEct'); //returns 'DataObject' |
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194 | * |
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195 | * @param string|object $nameOrObject The classname or object you want to normalise |
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196 | * @return string The normalised class name |
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197 | */ |
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198 | public static function class_name($nameOrObject) |
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206 | |||
207 | /** |
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208 | * Returns the passed class name along with all its parent class names in an |
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209 | * array, sorted with the root class first. |
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210 | * |
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211 | * @param string|object $nameOrObject Class or object instance |
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212 | * @param bool $tablesOnly Only return classes that have a table in the db. |
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213 | * @return array |
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214 | */ |
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215 | public static function ancestry($nameOrObject, $tablesOnly = false) |
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239 | |||
240 | /** |
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241 | * @param string $interfaceName |
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242 | * @return array A self-keyed array of class names. Note that this is only available with Silverstripe |
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243 | * classes and not built-in PHP classes. |
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244 | */ |
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245 | public static function implementorsOf($interfaceName) |
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249 | |||
250 | /** |
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251 | * Returns true if the given class implements the given interface |
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252 | * |
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253 | * @param string $className |
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254 | * @param string $interfaceName |
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255 | * @return bool |
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256 | */ |
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257 | public static function classImplements($className, $interfaceName) |
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261 | |||
262 | /** |
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263 | * Get all classes contained in a file. |
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264 | * @uses ManifestBuilder |
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265 | * |
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266 | * @todo Doesn't return additional classes that only begin |
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267 | * with the filename, and have additional naming separated through underscores. |
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268 | * |
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269 | * @param string $filePath Path to a PHP file (absolute or relative to webroot) |
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270 | * @return array |
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271 | */ |
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272 | View Code Duplication | public static function classes_for_file($filePath) |
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286 | |||
287 | /** |
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288 | * Returns all classes contained in a certain folder. |
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289 | * |
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290 | * @todo Doesn't return additional classes that only begin |
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291 | * with the filename, and have additional naming separated through underscores. |
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292 | * |
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293 | * @param string $folderPath Relative or absolute folder path |
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294 | * @return array Array of class names |
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295 | */ |
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296 | View Code Duplication | public static function classes_for_folder($folderPath) |
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310 | |||
311 | private static $method_from_cache = array(); |
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312 | |||
313 | public static function has_method_from($class, $method, $compclass) |
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335 | |||
336 | /** |
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337 | * @deprecated 4.0..5.0 |
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338 | */ |
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339 | public static function table_for_object_field($candidateClass, $fieldName) |
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344 | |||
345 | /** |
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346 | * Strip namespace from class |
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347 | * |
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348 | * @param string|object $nameOrObject Name of class, or instance |
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349 | * @return string Name of class without namespace |
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350 | */ |
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351 | public static function shortName($nameOrObject) |
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356 | |||
357 | /** |
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358 | * Helper to determine if the given object has a method |
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359 | * |
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360 | * @param object $object |
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361 | * @param string $method |
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362 | * @return bool |
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363 | */ |
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364 | public static function hasMethod($object, $method) |
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374 | |||
375 | /** |
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376 | * Parses a class-spec, such as "Versioned('Stage','Live')", as passed to create_from_string(). |
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377 | * Returns a 2-element array, with classname and arguments |
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378 | * |
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379 | * @param string $classSpec |
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380 | * @return array |
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381 | * @throws Exception |
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382 | */ |
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383 | public static function parse_class_spec($classSpec) |
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518 | } |
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519 |
In PHP, under loose comparison (like
==
, or!=
, orswitch
conditions), values of different types might be equal.For
string
values, the empty string''
is a special case, in particular the following results might be unexpected: