Complex classes like MasterSlavesConnection 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 MasterSlavesConnection, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 10 | class MasterSlavesConnection implements Connection |
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| 11 | { |
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| 12 | /** |
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| 13 | * configuration |
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| 14 | * |
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| 15 | * @var Master |
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| 16 | */ |
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| 17 | private $master; |
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| 18 | |||
| 19 | /** |
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| 20 | * configuration |
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| 21 | * |
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| 22 | * @var Slave[] |
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| 23 | */ |
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| 24 | private $slaves; |
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| 25 | |||
| 26 | /** |
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| 27 | * @var \Ez\DbLinker\Cache |
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| 28 | */ |
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| 29 | private $cache; |
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| 30 | |||
| 31 | /** |
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| 32 | * @var bool |
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| 33 | */ |
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| 34 | private $forceMaster = false; |
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| 35 | |||
| 36 | /** |
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| 37 | * @var int |
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| 38 | */ |
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| 39 | private $maxSlaveDelay = 30; |
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| 40 | |||
| 41 | /** |
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| 42 | * @var int |
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| 43 | */ |
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| 44 | private $slaveStatusCacheTtl = 10; |
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| 45 | |||
| 46 | /** |
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| 47 | * @var ExtendedServer |
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| 48 | */ |
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| 49 | private $lastConnection; |
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| 50 | |||
| 51 | public function __construct(array $master, array $slaves, $cache = null) |
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| 57 | |||
| 58 | public function disableCache(): void |
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| 62 | |||
| 63 | /** |
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| 64 | * @param array $slaves |
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| 65 | * @return Slave[] |
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| 66 | */ |
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| 67 | private function filteredSlaves(array $slaves): array |
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| 77 | |||
| 78 | /** |
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| 79 | * @param bool|null $forced |
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| 80 | * @return Connection |
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| 81 | * @throws \Doctrine\DBAL\DBALException |
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| 82 | */ |
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| 83 | public function masterConnection(bool $forced = null): Connection |
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| 91 | |||
| 92 | /** |
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| 93 | * @return Connection |
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| 94 | * @throws \Doctrine\DBAL\DBALException |
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| 95 | */ |
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| 96 | public function slaveConnection(): ?Connection |
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| 118 | |||
| 119 | /** |
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| 120 | * @param Slave[] $slaves |
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| 121 | * @return Slave|null |
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| 122 | */ |
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| 123 | private function randomSlave(array $slaves): ?Slave |
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| 137 | |||
| 138 | /** |
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| 139 | * @return ExtendedServer|null |
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| 140 | */ |
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| 141 | public function getLastConnection(): ?ExtendedServer |
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| 145 | |||
| 146 | /** |
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| 147 | * @return Slave[]|null |
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| 148 | */ |
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| 149 | public function slaves(): ?array |
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| 153 | |||
| 154 | /** |
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| 155 | * Prepares a statement for execution and returns a Statement object. |
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| 156 | * |
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| 157 | * @param string $prepareString |
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| 158 | * |
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| 159 | * @return \Doctrine\DBAL\Driver\Statement |
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| 160 | * @throws \Doctrine\DBAL\DBALException |
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| 161 | */ |
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| 162 | public function prepare($prepareString) |
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| 184 | |||
| 185 | public function forceMaster(bool $force): void |
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| 189 | |||
| 190 | /** |
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| 191 | * Executes an SQL statement, returning a result set as a Statement object. |
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| 192 | * |
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| 193 | * @return \Doctrine\DBAL\Driver\Statement |
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| 194 | * @throws \Doctrine\DBAL\DBALException |
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| 195 | */ |
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| 196 | public function query() |
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| 201 | |||
| 202 | /** |
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| 203 | * Quotes a string for use in a query. |
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| 204 | * |
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| 205 | * @param string $input |
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| 206 | * @param integer $type |
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| 207 | * |
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| 208 | * @return string |
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| 209 | * @throws \Doctrine\DBAL\DBALException |
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| 210 | */ |
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| 211 | public function quote($input, $type = \PDO::PARAM_STR) |
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| 215 | |||
| 216 | /** |
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| 217 | * Executes an SQL statement and return the number of affected rows. |
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| 218 | * |
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| 219 | * @param string $statement |
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| 220 | * |
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| 221 | * @return integer |
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| 222 | * @throws \Doctrine\DBAL\DBALException |
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| 223 | */ |
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| 224 | public function exec($statement) |
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| 228 | |||
| 229 | /** |
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| 230 | * Returns the ID of the last inserted row or sequence value. |
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| 231 | * |
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| 232 | * @param string|null $name |
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| 233 | * |
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| 234 | * @return string |
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| 235 | * @throws \Doctrine\DBAL\DBALException |
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| 236 | */ |
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| 237 | public function lastInsertId($name = null) |
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| 241 | |||
| 242 | /** |
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| 243 | * Initiates a transaction. |
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| 244 | * |
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| 245 | * @return boolean TRUE on success or FALSE on failure. |
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| 246 | * @throws \Doctrine\DBAL\DBALException |
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| 247 | */ |
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| 248 | public function beginTransaction() |
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| 252 | |||
| 253 | /** |
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| 254 | * Commits a transaction. |
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| 255 | * |
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| 256 | * @return boolean TRUE on success or FALSE on failure. |
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| 257 | * @throws \Doctrine\DBAL\DBALException |
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| 258 | */ |
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| 259 | public function commit() |
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| 263 | |||
| 264 | /** |
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| 265 | * Rolls back the current transaction, as initiated by beginTransaction(). |
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| 266 | * |
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| 267 | * @return boolean TRUE on success or FALSE on failure. |
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| 268 | * @throws \Doctrine\DBAL\DBALException |
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| 269 | */ |
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| 270 | public function rollBack() |
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| 274 | |||
| 275 | /** |
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| 276 | * Returns the error code associated with the last operation on the database handle. |
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| 277 | * |
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| 278 | * @return string|null The error code, or null if no operation has been run on the database handle. |
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| 279 | * @throws \Doctrine\DBAL\DBALException |
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| 280 | */ |
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| 281 | public function errorCode() |
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| 285 | |||
| 286 | /** |
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| 287 | * Returns extended error information associated with the last operation on the database handle. |
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| 288 | * |
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| 289 | * @return array |
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| 290 | * @throws \Doctrine\DBAL\DBALException |
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| 291 | */ |
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| 292 | public function errorInfo() |
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| 296 | |||
| 297 | private function hasCache() { |
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| 300 | |||
| 301 | private function getCacheKey(Slave $slave) { |
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| 304 | |||
| 305 | public function setSlaveStatus(Slave $slave, bool $running, int $delay = null): array |
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| 312 | |||
| 313 | private function isSlaveOK(Slave $slave): bool { |
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| 324 | } |
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| 325 |
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVarassignment in line 1 and the$higherassignment in line 2 are dead. The first because$myVaris never used and the second because$higheris always overwritten for every possible time line.