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 ZohoDatabasePusher 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 ZohoDatabasePusher, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 17 | class ZohoDatabasePusher |
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| 18 | { |
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| 19 | /** |
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| 20 | * @var Connection |
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| 21 | */ |
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| 22 | private $connection; |
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| 23 | |||
| 24 | /** |
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| 25 | * @var LoggerInterface |
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| 26 | */ |
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| 27 | private $logger; |
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| 28 | |||
| 29 | /** |
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| 30 | * @var string |
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| 31 | */ |
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| 32 | private $prefix; |
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| 33 | |||
| 34 | /** |
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| 35 | * @param Connection $connection |
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| 36 | * @param int $apiLimitInsertUpdateDelete |
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| 37 | * @param string $prefix |
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| 38 | * @param LoggerInterface $logger |
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| 39 | */ |
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| 40 | public function __construct(Connection $connection, $apiLimitInsertUpdateDelete = 100, $prefix = 'zoho_', LoggerInterface $logger = null) |
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| 54 | |||
| 55 | /** |
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| 56 | * @var int |
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| 57 | */ |
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| 58 | private $apiLimitInsertUpdateDelete; |
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| 59 | |||
| 60 | /** |
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| 61 | * @param AbstractZohoDao $zohoDao |
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| 62 | * @param bool $update |
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| 63 | * @return int |
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| 64 | */ |
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| 65 | private function countElementInTable(AbstractZohoDao $zohoDao, $update = false) |
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| 74 | |||
| 75 | /** |
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| 76 | * Insert or Update rows. |
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| 77 | * |
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| 78 | * @param AbstractZohoDao $zohoDao |
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| 79 | */ |
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| 80 | public function pushDataToZoho(AbstractZohoDao $zohoDao, $update = false) |
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| 137 | |||
| 138 | /** |
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| 139 | * @param AbstractZohoDao $zohoDao |
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| 140 | * @param ZohoBeanInterface[] $zohoBeans |
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| 141 | * @param string[] $rowsDeleted |
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| 142 | * @param bool $update |
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| 143 | */ |
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| 144 | private function sendDataToZohoCleanLocal(AbstractZohoDao $zohoDao, array $zohoBeans,$rowsDeleted, $update = false) |
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| 178 | |||
| 179 | /** |
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| 180 | * Insert data to bean in order to insert zoho records. |
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| 181 | * |
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| 182 | * @param AbstractZohoDao $dao |
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| 183 | * @param ZohoBeanInterface $zohoBean |
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| 184 | * @param array $row |
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| 185 | */ |
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| 186 | View Code Duplication | private function insertDataZohoBean(AbstractZohoDao $dao, ZohoBeanInterface $zohoBean, array $row) |
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| 200 | |||
| 201 | /** |
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| 202 | * Insert data to bean in order to update zoho records. |
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| 203 | * |
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| 204 | * @param ZohoBeanInterface $zohoBean |
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| 205 | * @param array $fieldsMatching |
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| 206 | * @param type $columnName |
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| 207 | * @param type $valueDb |
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| 208 | */ |
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| 209 | View Code Duplication | private function updateDataZohoBean(AbstractZohoDao $dao, ZohoBeanInterface $zohoBean, $columnName, $valueDb) |
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| 221 | |||
| 222 | /** |
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| 223 | * Change the value to the good format. |
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| 224 | * |
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| 225 | * @param string $type |
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| 226 | * @param mixed $value |
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| 227 | * |
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| 228 | * @return mixed |
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| 229 | */ |
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| 230 | private function formatValueToBeans($type, $value) |
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| 257 | |||
| 258 | /** |
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| 259 | * Run deleted rows to Zoho : local_delete. |
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| 260 | * |
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| 261 | * @param AbstractZohoDao $zohoDao |
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| 262 | */ |
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| 263 | public function pushDeletedRows(AbstractZohoDao $zohoDao) |
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| 282 | |||
| 283 | /** |
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| 284 | * Run inserted rows to Zoho : local_insert. |
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| 285 | * |
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| 286 | * @param AbstractZohoDao $zohoDao |
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| 287 | */ |
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| 288 | public function pushInsertedRows(AbstractZohoDao $zohoDao) |
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| 292 | |||
| 293 | /** |
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| 294 | * Run updated rows to Zoho : local_update. |
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| 295 | * |
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| 296 | * @param AbstractZohoDao $zohoDao |
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| 297 | */ |
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| 298 | public function pushUpdatedRows(AbstractZohoDao $zohoDao) |
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| 302 | |||
| 303 | /** |
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| 304 | * Push data from db to Zoho. |
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| 305 | * |
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| 306 | * @param AbstractZohoDao $zohoDao |
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| 307 | */ |
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| 308 | public function pushToZoho(AbstractZohoDao $zohoDao) |
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| 317 | } |
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| 318 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: