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 DAO 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 DAO, and based on these observations, apply Extract Interface, too.
1 | <?php |
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11 | abstract class DAO implements DAOInterface { |
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12 | |||
13 | /** @var \PDO */ |
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14 | protected $pdo; |
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15 | |||
16 | const JOIN = ''; |
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17 | |||
18 | protected $fixedFilter = []; |
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19 | |||
20 | /** @var string[] */ |
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21 | protected $selectCollumns = ['*']; |
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22 | |||
23 | /** @var boolean */ |
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24 | public static $debug = false; |
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25 | |||
26 | /** |
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27 | * Retorna um objeto a partir da linha da tabela |
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28 | * @param array[] $row |
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29 | */ |
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30 | abstract protected function mapObject($row); |
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31 | |||
32 | /** |
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33 | * Retorna a linha da tabela a partir de um objeto |
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34 | * @param object $obj |
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35 | */ |
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36 | abstract protected function mapRow($obj); |
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37 | |||
38 | /** |
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39 | * Valida os campos retornando string de Erro ou Null |
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40 | * @return string|null |
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41 | */ |
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42 | abstract protected function validate(); |
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43 | |||
44 | /** Inicia o DAO */ |
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45 | public function __construct() { |
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48 | |||
49 | /** |
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50 | * Define uma conexão manualmente |
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51 | * @param \PDO $pdo |
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52 | */ |
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53 | public function setPDO($pdo) { |
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56 | |||
57 | /** |
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58 | * Define quais colunas serão consultadas no SELECT |
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59 | * @param string[] $collumns |
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60 | */ |
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61 | public function setSelectCollumns(array $collumns) { |
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64 | |||
65 | /** |
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66 | * Adiciona nova coluna no SELECT |
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67 | * @param string $collumn |
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68 | */ |
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69 | public function addSelectCollumn($collumn) { |
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74 | |||
75 | /** |
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76 | * Salva o registro |
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77 | * @param object $obj |
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78 | * @return string|null |
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79 | */ |
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80 | public function save($obj) { |
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97 | |||
98 | /** Insere o registro */ |
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99 | protected function insert() { |
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113 | |||
114 | /** Atualiza o registro */ |
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115 | protected function update() { |
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133 | |||
134 | /** |
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135 | * @param $stmt \PDOStatement |
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136 | * @return string erro |
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137 | */ |
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138 | protected function error(\PDOStatement $stmt) { |
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148 | |||
149 | /** |
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150 | * Exclui o registro |
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151 | * @param object $obj |
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152 | */ |
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153 | public function delete($obj) { |
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156 | |||
157 | /** |
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158 | * Exclui o registro por id |
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159 | * @param int $id |
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160 | */ |
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161 | public function deleteById($id) { |
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164 | |||
165 | /** |
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166 | * Exclui o registro por id |
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167 | * @param string $name |
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168 | * * @param mixed $value |
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169 | */ |
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170 | public function deleteByField($name, $value) { |
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179 | |||
180 | /** |
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181 | * Busca o objeto pelo id |
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182 | * @param int $id |
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183 | */ |
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184 | public function fetchById($id) { |
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187 | |||
188 | /** |
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189 | * Busca o objeto por um campo/atributo específico |
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190 | * @param string $name Nome do atributo |
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191 | * @param mixed $value Valor do atributo |
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192 | */ |
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193 | public function fetchByField($name, $value) { |
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196 | |||
197 | /** |
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198 | * Busca o objeto |
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199 | * @param string[] $filters Array de filtros |
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200 | * @param string $option [Order by, Limit, etc] |
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201 | */ |
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202 | public function fetch($filters, $option = 'ORDER BY 1 DESC') { |
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217 | |||
218 | /** |
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219 | * Retorna todos os registros |
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220 | * |
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221 | * <code> |
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222 | * $dao->fetchAll( ['id = ?' => 10]); |
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223 | * </code> |
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224 | * @param string[] $filters Array de filtros |
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225 | * @param string $option [Order by, Limit, etc] |
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226 | */ |
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227 | public function fetchAll($filters = [], $option = 'ORDER BY 1 DESC') { |
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246 | |||
247 | /** |
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248 | * Retorna comando SELECT |
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249 | * @param string $selectCollumns |
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250 | * @return string |
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251 | * @example "SELECT * FROM user" |
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252 | */ |
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253 | protected function selectSQL($selectCollumns = ['*']) { |
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256 | |||
257 | /** |
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258 | * Retorna comando WHERE |
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259 | * @param string[] $filters |
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260 | * @return string |
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261 | */ |
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262 | protected function whereSQL(&$filters) { |
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266 | |||
267 | /** |
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268 | * Retorna o total de registros |
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269 | * @param string[] $filters Array de filtros |
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270 | * @param string $option |
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271 | * @return int |
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272 | */ |
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273 | public function numRows($filters = [], $option = 'ORDER BY 1 DESC') { |
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291 | |||
292 | /** |
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293 | * Retorna True se objeto existir |
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294 | * @return boolean |
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295 | */ |
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296 | protected function objExists($obj) { |
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299 | |||
300 | /** Define como Página 404 se o objeto não existir */ |
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301 | public function checkFoundRegistry($obj) { |
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307 | |||
308 | /** |
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309 | * Exibe comando SQL, se debug está habilitado |
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310 | * @param string $sql |
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311 | * @param mixed[] $values |
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312 | */ |
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313 | protected function debug($sql, $values = []) { |
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320 | |||
321 | private function getFilterValues($filters) { |
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324 | |||
325 | protected function beforeSave() { |
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328 | |||
329 | protected function afterSave() { |
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332 | |||
333 | } |
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334 |
In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:
Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion: