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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| 21 | |||
| 22 | /** |
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| 23 | * The current record in the interator. |
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| 24 | * |
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| 25 | * @var array |
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| 26 | */ |
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| 27 | protected $currentRecord = null; |
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| 28 | |||
| 29 | /** |
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| 30 | * The number of the current row in the interator. |
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| 31 | * |
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| 32 | * @var int |
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| 33 | */ |
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| 34 | protected $rowNum = -1; |
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| 35 | |||
| 36 | /** |
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| 37 | * Flag to keep track of whether iteration has begun, to prevent unnecessary seeks |
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| 38 | * |
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| 39 | * @var bool |
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| 40 | */ |
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| 41 | protected $queryHasBegun = false; |
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| 42 | |||
| 43 | /** |
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| 44 | * Return an array containing all the values from a specific column. If no column is set, then the first will be |
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| 45 | * returned |
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| 46 | * |
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| 47 | * @param string $column |
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| 48 | * @return array |
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| 49 | */ |
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| 50 | public function column($column = null) { |
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| 63 | |||
| 64 | /** |
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| 65 | * Return an array containing all values in the leftmost column, where the keys are the |
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| 66 | * same as the values. |
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| 67 | * |
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| 68 | * @return array |
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| 69 | */ |
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| 70 | View Code Duplication | public function keyedColumn() { |
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| 78 | |||
| 79 | /** |
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| 80 | * Return a map from the first column to the second column. |
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| 81 | * |
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| 82 | * @return array |
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| 83 | */ |
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| 84 | View Code Duplication | public function map() { |
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| 93 | |||
| 94 | /** |
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| 95 | * Returns the next record in the iterator. |
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| 96 | * |
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| 97 | * @return array |
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| 98 | */ |
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| 99 | public function record() { |
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| 102 | |||
| 103 | /** |
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| 104 | * Returns the first column of the first record. |
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| 105 | * |
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| 106 | * @return string |
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| 107 | */ |
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| 108 | public function value() { |
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| 112 | |||
| 113 | /** |
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| 114 | * Return an HTML table containing the full result-set |
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| 115 | * |
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| 116 | * @return string |
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| 117 | */ |
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| 118 | public function table() { |
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| 144 | |||
| 145 | /** |
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| 146 | * Iterator function implementation. Rewind the iterator to the first item and return it. |
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| 147 | * Makes use of {@link seek()} and {@link numRecords()}, takes care of the plumbing. |
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| 148 | * |
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| 149 | * @return array |
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| 150 | */ |
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| 151 | public function rewind() { |
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| 158 | |||
| 159 | /** |
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| 160 | * Iterator function implementation. Return the current item of the iterator. |
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| 161 | * |
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| 162 | * @return array |
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| 163 | */ |
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| 164 | public function current() { |
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| 171 | |||
| 172 | /** |
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| 173 | * Iterator function implementation. Return the first item of this iterator. |
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| 174 | * |
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| 175 | * @return array |
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| 176 | */ |
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| 177 | public function first() { |
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| 181 | |||
| 182 | /** |
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| 183 | * Iterator function implementation. Return the row number of the current item. |
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| 184 | * |
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| 185 | * @return int |
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| 186 | */ |
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| 187 | public function key() { |
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| 190 | |||
| 191 | /** |
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| 192 | * Iterator function implementation. Return the next record in the iterator. |
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| 193 | * Makes use of {@link nextRecord()}, takes care of the plumbing. |
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| 194 | * |
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| 195 | * @return array |
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| 196 | */ |
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| 197 | public function next() { |
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| 203 | |||
| 204 | /** |
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| 205 | * Iterator function implementation. Check if the iterator is pointing to a valid item. |
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| 206 | * |
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| 207 | * @return bool |
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| 208 | */ |
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| 209 | public function valid() { |
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| 213 | |||
| 214 | /** |
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| 215 | * Return the next record in the query result. |
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| 216 | * |
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| 217 | * @return array |
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| 218 | */ |
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| 219 | abstract public function nextRecord(); |
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| 220 | |||
| 221 | /** |
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| 222 | * Return the total number of items in the query result. |
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| 223 | * |
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| 224 | * @return int |
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| 225 | */ |
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| 226 | abstract public function numRecords(); |
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| 227 | |||
| 228 | /** |
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| 229 | * Go to a specific row number in the query result and return the record. |
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| 230 | * |
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| 231 | * @param int $rowNum Row number to go to. |
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| 232 | * @return array |
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| 233 | */ |
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| 234 | abstract public function seek($rowNum); |
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| 235 | } |
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| 236 |
In PHP, under loose comparison (like
==, or!=, orswitchconditions), values of different types might be equal.For
stringvalues, the empty string''is a special case, in particular the following results might be unexpected: