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:
1 | <?php |
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15 | class CustomSelects |
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16 | { |
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17 | const TYPE_SIMPLE = 'simple'; |
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18 | const TYPE_COMPLEX = 'complex'; |
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19 | const TYPE_STRUCTURED = 'structured'; |
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20 | |||
21 | private $valid_operators = array('COUNT', 'SUM'); |
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22 | |||
23 | |||
24 | /** |
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25 | * Original incoming select array |
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26 | * @var array |
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27 | */ |
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28 | private $original_selects; |
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29 | |||
30 | /** |
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31 | * Select string that can be added to the query |
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32 | * @var string |
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33 | */ |
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34 | private $columns_to_select_expression; |
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35 | |||
36 | |||
37 | /** |
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38 | * An array of aliases for the columns included in the incoming select array. |
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39 | * @var array |
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40 | */ |
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41 | private $column_aliases_in_select; |
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42 | |||
43 | |||
44 | /** |
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45 | * Enum representation of the "type" of array coming into this value object. |
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46 | * @var string |
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47 | * |
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48 | */ |
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49 | private $type = ''; |
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50 | |||
51 | |||
52 | /** |
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53 | * CustomSelects constructor. |
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54 | * Incoming selects can be in one of the following formats: |
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55 | * ---- self::TYPE_SIMPLE array ---- |
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56 | * This is considered the "simple" type. In this case the array is an numerically indexed array with single or |
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57 | * multiple columns to select as the values. |
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58 | * eg. array( 'ATT_ID', 'REG_ID' ) |
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59 | * eg. array( '*' ) |
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60 | * If you want to use the columns in any WHERE, GROUP BY, or HAVING clauses, you must instead use the "complex" or |
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61 | * "structured" method. |
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62 | * ---- self::TYPE_COMPLEX array ---- |
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63 | * This is considered the "complex" type. In this case the array is indexed by arbitrary strings that serve as |
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64 | * column alias, and the value is an numerically indexed array where there are two values. The first value (0) is |
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65 | * the selection and the second value (1) is the data type. Data types must be one of the types defined in |
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66 | * EEM_Base::$_valid_wpdb_data_types. |
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67 | * eg. array( 'count' => array('count(REG_ID)', '%d') ) |
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68 | * Complex array configuration allows for using the column alias in any WHERE, GROUP BY, or HAVING clauses. |
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69 | * ---- self::TYPE_STRUCTURED array --- |
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70 | * This is considered the "structured" type. This type is similar to the complex type except that the array attached |
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71 | * to the column alias contains three values. The first value is the qualified column name (which can include |
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72 | * join syntax for models). The second value is the operator performed on the column (i.e. 'COUNT', 'SUM' etc)., |
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73 | * the third value is the data type. Note, if the select does not have an operator, you can use an empty string for |
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74 | * the second value. |
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75 | * Note: for now SUM is only for simple single column expressions (i.e. SUM(Transaction.TXN_total)) |
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76 | * eg. array( 'registration_count' => array('Registration.REG_ID', 'count', '%d') ); |
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77 | * |
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78 | * NOTE: mixing array types in the incoming $select will cause errors. |
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79 | * |
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80 | * @param array $selects |
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81 | * @throws InvalidArgumentException |
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82 | */ |
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83 | public function __construct(array $selects) |
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89 | |||
90 | |||
91 | /** |
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92 | * Derives what type of custom select has been sent in. |
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93 | * @param array $selects |
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94 | * @throws InvalidArgumentException |
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95 | */ |
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96 | private function deriveType(array $selects) |
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142 | |||
143 | |||
144 | /** |
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145 | * Sets up the various properties for the vo depending on type. |
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146 | * @param array $selects |
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147 | * @throws InvalidArgumentException |
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148 | */ |
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149 | private function deriveParts(array $selects) |
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176 | |||
177 | |||
178 | /** |
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179 | * Validates self::TYPE_COMPLEX and self::TYPE_STRUCTURED select statement parts. |
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180 | * @param array $select_parts |
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181 | * @param string $alias |
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182 | * @throws InvalidArgumentException |
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183 | */ |
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184 | private function validateSelectValueForType(array $select_parts, $alias) |
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220 | |||
221 | |||
222 | /** |
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223 | * Each type will have an expected count of array elements, this returns what that expected count is. |
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224 | * @param string $type |
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225 | * @return int |
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226 | */ |
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227 | private function expectedSelectPartCountForType($type = '') { |
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235 | |||
236 | |||
237 | /** |
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238 | * Prepares the select statement part for for structured type selects. |
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239 | * @param array $select_parts |
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240 | * @param string $alias |
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241 | * @return string |
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242 | * @throws InvalidArgumentException |
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243 | */ |
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244 | private function assembleSelectStringWithOperator(array $select_parts, $alias) |
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263 | |||
264 | |||
265 | /** |
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266 | * Return the datatype from the given select part. |
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267 | * Remember the select_part has already been validated on object instantiation. |
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268 | * @param array $select_part |
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269 | * @return string |
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270 | */ |
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271 | private function getDataTypeForSelectType(array $select_part) |
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282 | |||
283 | |||
284 | /** |
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285 | * Returns the original select array sent into the VO. |
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286 | * @return array |
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287 | */ |
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288 | public function originalSelects() |
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292 | |||
293 | |||
294 | /** |
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295 | * Returns the final assembled select expression derived from the incoming select array. |
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296 | * @return string |
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297 | */ |
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298 | public function columnsToSelectExpression() |
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302 | |||
303 | |||
304 | /** |
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305 | * Returns all the column aliases derived from the incoming select array. |
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306 | * @return array |
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307 | */ |
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308 | public function columnAliases() |
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312 | |||
313 | |||
314 | /** |
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315 | * Returns the enum type for the incoming select array. |
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316 | * @return string |
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317 | */ |
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318 | public function type() |
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322 | |||
323 | |||
324 | |||
325 | /** |
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326 | * Return the datatype for the given column_alias |
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327 | * @param string $column_alias |
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328 | * @return string |
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329 | */ |
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330 | public function getDataTypeForAlias($column_alias) |
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338 | } |
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339 |