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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25 | class JoinKeyword extends Component |
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26 | { |
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27 | |||
28 | /** |
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29 | * Types of join. |
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30 | * |
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31 | * @var array |
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32 | */ |
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33 | public static $JOINS = array( |
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34 | 'FULL JOIN' => 'FULL', |
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35 | 'INNER JOIN' => 'INNER', |
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36 | 'JOIN' => 'JOIN', |
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37 | 'LEFT JOIN' => 'LEFT', |
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38 | 'LEFT OUTER JOIN' => 'LEFT', |
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39 | 'RIGHT JOIN' => 'RIGHT', |
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40 | 'RIGHT OUTER JOIN' => 'RIGHT', |
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41 | 'STRAIGHT_JOIN' => 'STRAIGHT', |
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42 | ); |
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43 | |||
44 | /** |
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45 | * Type of this join. |
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46 | * |
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47 | * @see static::$JOINS |
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48 | * @var string |
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49 | */ |
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50 | public $type; |
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51 | |||
52 | /** |
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53 | * Join expression. |
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54 | * |
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55 | * @var Expression |
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56 | */ |
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57 | public $expr; |
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58 | |||
59 | /** |
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60 | * Join conditions. |
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61 | * |
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62 | * @var Condition[] |
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63 | */ |
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64 | public $on; |
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65 | /** |
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66 | * Columns in Using clause |
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67 | * |
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68 | * @var ArrayObj |
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69 | */ |
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70 | public $using; |
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71 | |||
72 | /** |
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73 | * @param Parser $parser The parser that serves as context. |
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74 | * @param TokensList $list The list of tokens that are being parsed. |
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75 | * @param array $options Parameters for parsing. |
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76 | * |
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77 | * @return JoinKeyword[] |
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78 | */ |
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79 | 6 | public static function parse(Parser $parser, TokensList $list, array $options = array()) |
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171 | |||
172 | /** |
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173 | * @param JoinKeyword[] $component The component to be built. |
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174 | * @param array $options Parameters for building. |
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175 | * |
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176 | * @return string |
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177 | */ |
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178 | 2 | public static function build($component, array $options = array()) |
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189 | } |
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190 |
This check looks for multiple assignments in successive lines of code. It will report an issue if the operators are not in a straight line.
To visualize
will produce issues in the first and second line, while this second example
will produce no issues.