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 KeyDescriptor 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 KeyDescriptor, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 52 | class KeyDescriptor |
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| 53 | { |
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| 54 | /** |
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| 55 | * Holds collection of named key values |
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| 56 | * For e.g. the keypredicate Order_Details(OrderID=10248,ProductID=11) will |
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| 57 | * stored in this array as: |
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| 58 | * Array([OrderID] => Array( [0] => 10248 [1] => Object(Int32)), |
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| 59 | * [ProductID] => Array( [0] => 11 [1] => Object(Int32))) |
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| 60 | * Note: This is mutually exclusive with $_positionalValues. These values |
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| 61 | * are not validated aganist entity's ResourceType, validation will happen |
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| 62 | * once validate function is called, $_validatedNamedValues will hold |
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| 63 | * validated values. |
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| 64 | * |
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| 65 | * @var array |
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| 66 | */ |
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| 67 | private $namedValues = []; |
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| 68 | |||
| 69 | /** |
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| 70 | * Holds collection of positional key values |
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| 71 | * For e.g. the keypredicate Order_Details(10248, 11) will |
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| 72 | * stored in this array as: |
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| 73 | * Array([0] => Array( [0] => 10248 [1] => Object(Int32)), |
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| 74 | * [1] => Array( [0] => 11 [1] => Object(Int32))) |
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| 75 | * Note: This is mutually exclusive with $_namedValues. These values are not |
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| 76 | * validated aganist entity's ResourceType, validation will happen once validate |
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| 77 | * function is called, $_validatedNamedValues will hold validated values. |
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| 78 | * |
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| 79 | * @var array |
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| 80 | */ |
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| 81 | private $positionalValues = []; |
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| 82 | |||
| 83 | /** |
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| 84 | * Holds collection of positional or named values as named values. The validate |
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| 85 | * function populates this collection. |
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| 86 | * |
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| 87 | * @var array |
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| 88 | */ |
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| 89 | private $validatedNamedValues = []; |
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| 90 | |||
| 91 | /** |
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| 92 | * Creates new instance of KeyDescriptor |
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| 93 | * Note: The arguments $namedValues and $positionalValues are mutually |
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| 94 | * exclusive. Either both or one will be empty array. |
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| 95 | * |
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| 96 | * @param array $namedValues Collection of named key values |
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| 97 | * @param array $positionalValues Collection of positional key values |
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| 98 | */ |
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| 99 | private function __construct(array $namedValues, array $positionalValues) |
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| 105 | |||
| 106 | /** |
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| 107 | * Gets collection of named key values. |
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| 108 | * |
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| 109 | * @return array[] |
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| 110 | */ |
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| 111 | public function getNamedValues() |
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| 115 | |||
| 116 | /** |
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| 117 | * Gets collection of positional key values. |
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| 118 | * |
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| 119 | * @return array[] |
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| 120 | */ |
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| 121 | public function getPositionalValues() |
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| 125 | |||
| 126 | /** |
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| 127 | * Gets collection of positional key values by reference. |
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| 128 | * |
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| 129 | * @return array[] |
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| 130 | */ |
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| 131 | public function &getPositionalValuesByRef() |
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| 135 | |||
| 136 | /** |
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| 137 | * Gets validated named key values, this array will be populated |
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| 138 | * in validate function. |
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| 139 | * |
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| 140 | * @throws InvalidOperationException If this function invoked before invoking validate function |
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| 141 | * |
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| 142 | * @return array[] |
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| 143 | */ |
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| 144 | public function getValidatedNamedValues() |
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| 154 | |||
| 155 | /** |
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| 156 | * Checks whether the key values have name. |
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| 157 | * |
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| 158 | * @return bool |
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| 159 | */ |
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| 160 | public function areNamedValues() |
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| 164 | |||
| 165 | /** |
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| 166 | * Check whether this KeyDesciption has any key values. |
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| 167 | * |
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| 168 | * @return bool |
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| 169 | */ |
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| 170 | public function isEmpty() |
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| 175 | |||
| 176 | /** |
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| 177 | * Gets number of values in the key. |
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| 178 | * |
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| 179 | * @return int |
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| 180 | */ |
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| 181 | public function valueCount() |
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| 191 | |||
| 192 | /** |
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| 193 | * Attempts to parse value(s) of resource key(s) from the given key predicate |
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| 194 | * and creates instance of KeyDescription representing the same, Once parsing |
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| 195 | * is done one should call validate function to validate the created |
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| 196 | * KeyDescription. |
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| 197 | * |
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| 198 | * @param string $keyPredicate The predicate to parse |
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| 199 | * @param KeyDescriptor KeyDescriptor On return, Description of key after |
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| 200 | * parsing |
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| 201 | * |
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| 202 | * @return bool True if the given values were parsed; false if there was a syntax error |
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| 203 | */ |
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| 204 | public static function tryParseKeysFromKeyPredicate( |
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| 215 | |||
| 216 | /** |
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| 217 | * Attempt to parse comma seperated values representing a skiptoken and creates |
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| 218 | * instance of KeyDescriptor representing the same. |
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| 219 | * |
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| 220 | * @param string $skipToken The skiptoken value to parse |
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| 221 | * @param KeyDescriptor &$keyDescriptor On return, Description of values |
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| 222 | * after parsing |
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| 223 | * |
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| 224 | * @return bool True if the given values were parsed; false if there was a syntax error |
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| 225 | */ |
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| 226 | public static function tryParseValuesFromSkipToken($skipToken, &$keyDescriptor) |
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| 235 | |||
| 236 | /** |
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| 237 | * Validate this KeyDescriptor, If valid, this function populates |
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| 238 | * _validatedNamedValues array with key as keyName and value as an array of |
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| 239 | * key value and key type. |
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| 240 | * |
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| 241 | * @param string $segmentAsString The segment in the form identifier |
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| 242 | * (keyPredicate) which this descriptor |
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| 243 | * represents |
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| 244 | * @param ResourceType $resourceType The type of the identifier in the segment |
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| 245 | * |
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| 246 | * @throws ODataException If validation fails |
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| 247 | */ |
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| 248 | public function validate($segmentAsString, ResourceType $resourceType) |
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| 334 | |||
| 335 | /** |
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| 336 | * Attempts to parse value(s) of resource key(s) from the key predicate and |
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| 337 | * creates instance of KeyDescription representing the same, Once parsing is |
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| 338 | * done, one should call validate function to validate the created KeyDescription. |
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| 339 | * |
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| 340 | * @param string $keyPredicate The key predicate to parse |
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| 341 | * @param bool $allowNamedValues Set to true if parser should accept |
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| 342 | * named values(Property = KeyValue), |
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| 343 | * if false then parser will fail on |
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| 344 | * such constructs |
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| 345 | * @param bool $allowNull Set to true if parser should accept |
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| 346 | * null values for positional key |
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| 347 | * values, if false then parser will |
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| 348 | * fail on seeing null values |
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| 349 | * @param KeyDescriptor &$keyDescriptor On return, Description of key after |
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| 350 | * parsing |
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| 351 | * |
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| 352 | * @return bool True if the given values were parsed; false if there was a syntax error |
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| 353 | */ |
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| 354 | private static function tryParseKeysFromRawKeyPredicate( |
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| 456 | |||
| 457 | /** |
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| 458 | * Get the type of an Astoria URI key value, validate the value against the type. If valid, this function |
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| 459 | * provides the PHP value equivalent to the Astoria URI key value. |
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| 460 | * |
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| 461 | * @param string $value The Astoria URI key value |
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| 462 | * @param ExpressionTokenId $tokenId The tokenId for $value literal |
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| 463 | * @param mixed|null &$outValue After the invocation, this parameter holds the PHP equivalent to $value, |
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| 464 | * if $value is not valid then this parameter will be null |
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| 465 | * @param IType|null &$outType After the invocation, this parameter holds the type of $value, if $value is |
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| 466 | * not a valid key value type then this parameter will be null |
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| 467 | * |
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| 468 | * @return bool True if $value is a valid type, else false |
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| 469 | */ |
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| 470 | private static function getTypeAndValidateKeyValue($value, $tokenId, &$outValue, &$outType) |
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| 517 | } |
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| 518 |