Complex classes like DataType 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 DataType, and based on these observations, apply Extract Interface, too.
1 | <?php declare(strict_types = 1); |
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25 | abstract class DataType extends PrettyJsonSerializable |
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26 | { |
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27 | use Constructor; |
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28 | |||
29 | const FIELDS = []; |
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30 | |||
31 | /** |
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32 | * Get field definition from FIELDS, including parent classes. |
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33 | */ |
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34 | protected static function fieldType(string $field) |
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44 | |||
45 | private function fieldException(string $field, string $message) |
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46 | { |
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47 | return new InvalidArgumentException( |
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48 | get_called_class() . "->$field must $message" |
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49 | ); |
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50 | } |
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51 | |||
52 | protected function setField($field, $value, bool $strict = true) |
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53 | { |
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54 | try { |
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55 | $this->setFieldStrict("$field", $value); |
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56 | } catch (InvalidArgumentException $e) { |
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57 | if ($strict) { |
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58 | throw $e; |
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59 | } |
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60 | } |
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61 | } |
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62 | |||
63 | protected function setFieldStrict(string $field, $value) |
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64 | { |
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65 | if ($field == '@context') { |
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66 | return; |
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67 | } |
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68 | |||
69 | $type = static::fieldType($field); |
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70 | if (!$type) { |
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71 | throw new InvalidArgumentException( |
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72 | get_called_class() . "->$field does not exist" |
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73 | ); |
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74 | } |
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75 | |||
76 | if (is_null($value)) { |
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77 | $value = null; |
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78 | } elseif (is_array($type)) { # Set or Listing |
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79 | if ($type[0] == 'Set') { |
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80 | if (!($value instanceof Set)) { |
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81 | if (is_array($value)) { |
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82 | $class = 'JSKOS\\' . $type[1]; |
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83 | $value = new Set( |
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84 | array_map(function ($m) use ($class) { |
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85 | if (is_null($m)) { |
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86 | return null; |
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87 | } |
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88 | if ($m instanceof $class) { |
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89 | return $m; |
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90 | } |
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91 | return new $class($m); |
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92 | }, $value) |
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93 | ); |
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94 | } else { |
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95 | throw $this->fieldException($field, "be a Set"); |
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96 | } |
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97 | } |
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98 | # TODO: check member types |
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99 | } else { # Listing |
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100 | if (!($value instanceof Listing)) { |
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101 | if (is_array($value)) { |
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102 | $value = new Listing($value); |
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103 | } else { |
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104 | throw $this->fieldException($field, "be a Listing"); |
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105 | } |
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106 | } |
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107 | # TODO: check member types |
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108 | } |
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109 | } elseif (in_array($type, ['LanguageMapOfStrings', 'LanguageMapOfLists', 'ConceptScheme', 'Item'])) { |
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110 | $type = "JSKOS\\$type"; |
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111 | if (!($value instanceof $type)) { |
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112 | $value = new $type($value); |
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113 | } |
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114 | } elseif ($type != '*' && !DataType::hasType($value, $type)) { |
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115 | throw $this->fieldException($field, "match JSKOS\DataType::is$type"); |
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116 | } |
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117 | |||
118 | $this->$field = $value; |
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119 | } |
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120 | |||
121 | public function __set($field, $value) |
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125 | |||
126 | public function &__get($field) |
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143 | |||
144 | public function __isset($field): bool |
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148 | |||
149 | /** |
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150 | * Check whether a given value looks like an URI. |
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151 | */ |
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152 | public static function isURI($uri): bool |
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156 | |||
157 | /** |
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158 | * Check whether a given value looks like an http/https URL. |
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159 | */ |
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160 | public static function isURL($url): bool |
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166 | |||
167 | /** |
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168 | * Check whether a given value looks like a date. |
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169 | */ |
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170 | public static function isDate($date): bool |
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174 | |||
175 | /** |
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176 | * Check whether a given value looks like a language tag. |
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177 | */ |
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178 | public static function isLanguage($language): bool |
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182 | |||
183 | /** |
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184 | * Check whether a given value looks like a language range. |
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185 | */ |
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186 | public static function isLanguageRange($range): bool |
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190 | |||
191 | /** |
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192 | * Check whether a given value looks like a language or language range. |
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193 | */ |
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194 | public static function isLanguageOrRange($language): bool |
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200 | |||
201 | /** |
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202 | * Check whether a given value is a string. |
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203 | */ |
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204 | public static function isString($string): bool |
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208 | |||
209 | /** |
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210 | * Check whether a given value is a non-negative integer |
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211 | */ |
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212 | public static function isNonNegativeInteger($value): bool |
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216 | |||
217 | /** |
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218 | * Check whether a given value is a percentage |
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219 | */ |
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220 | public static function isPercentage($value): bool |
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224 | |||
225 | /** |
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226 | * Check whether a given value is a concept scheme |
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227 | */ |
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228 | public static function isConceptScheme($scheme): bool |
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232 | |||
233 | /** |
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234 | * Check whether a given value is of given type. |
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235 | */ |
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236 | public static function hasType($value, string $type): bool |
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241 | } |
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242 |
PHP has two types of connecting operators (logical operators, and boolean operators):
and
&&
or
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The difference between these is the order in which they are executed. In most cases, you would want to use a boolean operator like
&&
, or||
.Let’s take a look at a few examples:
Logical Operators are used for Control-Flow
One case where you explicitly want to use logical operators is for control-flow such as this:
Since
die
introduces problems of its own, f.e. it makes our code hardly testable, and prevents any kind of more sophisticated error handling; you probably do not want to use this in real-world code. Unfortunately, logical operators cannot be combined withthrow
at this point:These limitations lead to logical operators rarely being of use in current PHP code.