Complex classes like Chain 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 Chain, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 20 | class Chain  | 
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| 21 | { | 
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| 22 | /**  | 
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| 23 | * The key we want to validate.  | 
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| 24 | *  | 
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| 25 | * @var string  | 
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| 26 | */  | 
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| 27 | protected $key;  | 
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| 28 | |||
| 29 | /**  | 
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| 30 | * The name that we can use in error messages.  | 
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| 31 | *  | 
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| 32 | * @var string  | 
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| 33 | */  | 
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| 34 | protected $name;  | 
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| 35 | |||
| 36 | /**  | 
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| 37 | * The array of all rules for this chain.  | 
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| 38 | *  | 
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| 39 | * @var Rule[]  | 
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| 40 | */  | 
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| 41 | protected $rules = [];  | 
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| 42 | |||
| 43 | /**  | 
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| 44 | * The message stack to append messages to.  | 
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| 45 | *  | 
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| 46 | * @var MessageStack  | 
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| 47 | */  | 
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| 48 | protected $messageStack;  | 
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| 49 | |||
| 50 | /**  | 
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| 51 | * Construct the chain.  | 
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| 52 | *  | 
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| 53 | * @param string $key  | 
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| 54 | * @param string $name  | 
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| 55 | * @param bool $required  | 
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| 56 | * @param bool $allowEmpty  | 
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| 57 | */  | 
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| 58 | 207 | public function __construct($key, $name, $required, $allowEmpty)  | 
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| 59 |     { | 
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| 60 | 207 | $this->key = $key;  | 
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| 61 | 207 | $this->name = $name;  | 
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| 62 | |||
| 63 | 207 | $this->addRule(new Rule\Required($required));  | 
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| 64 | 207 | $this->addRule(new Rule\NotEmpty($allowEmpty));  | 
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| 65 | 207 | }  | 
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| 66 | |||
| 67 | /**  | 
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| 68 | * Overwrite the default __clone behaviour to make sure the rules are cloned too.  | 
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| 69 | */  | 
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| 70 | 3 | public function __clone()  | 
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| 71 |     { | 
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| 72 | 3 | $rules = [];  | 
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| 73 | 3 |         foreach ($this->rules as $rule) { | 
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| 74 | 3 | $rules[] = clone $rule;  | 
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| 75 | 3 | }  | 
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| 76 | 3 | $this->rules = $rules;  | 
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| 77 | 3 | }  | 
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| 78 | |||
| 79 | /**  | 
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| 80 | * Validate the value to consist only out of alphanumeric characters.  | 
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| 81 | *  | 
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| 82 | * @param bool $allowWhitespace  | 
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| 83 | * @return $this  | 
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| 84 | */  | 
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| 85 | 7 | public function alnum($allowWhitespace = false)  | 
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| 89 | |||
| 90 | /**  | 
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| 91 | * Validate that the value only consists our of alphabetic characters.  | 
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| 92 | *  | 
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| 93 | * @param bool $allowWhitespace  | 
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| 94 | * @return $this  | 
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| 95 | */  | 
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| 96 | 7 | public function alpha($allowWhitespace = false)  | 
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| 100 | |||
| 101 | /**  | 
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| 102 | * Validate that the value is between $min and $max (inclusive).  | 
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| 103 | *  | 
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| 104 | * @param int $min  | 
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| 105 | * @param int $max  | 
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| 106 | * @return $this  | 
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| 107 | */  | 
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| 108 | 6 | public function between($min, $max)  | 
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| 109 |     { | 
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| 110 | 6 | return $this->addRule(new Rule\Between($min, $max));  | 
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| 111 | }  | 
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| 112 | |||
| 113 | /**  | 
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| 114 | * Validate that the value is a boolean.  | 
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| 115 | *  | 
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| 116 | * @return $this  | 
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| 117 | */  | 
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| 118 | 9 | public function bool()  | 
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| 122 | |||
| 123 | /**  | 
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| 124 | * Validate by executing a callback function, and returning its result.  | 
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| 125 | *  | 
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| 126 | * @param callable $callable  | 
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| 127 | * @return $this  | 
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| 128 | */  | 
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| 129 | 5 | public function callback(callable $callable)  | 
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| 133 | |||
| 134 | /**  | 
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| 135 | * Validates that the value is a valid credit card number.  | 
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| 136 | * @return $this  | 
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| 137 | */  | 
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| 138 | 15 | public function creditCard()  | 
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| 142 | |||
| 143 | /**  | 
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| 144 | * Validates that the value is a date. If format is passed, it *must* be in that format.  | 
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| 145 | *  | 
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| 146 | * @param string|null $format  | 
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| 147 | * @return $this  | 
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| 148 | */  | 
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| 149 | 8 | public function datetime($format = null)  | 
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| 153 | |||
| 154 | /**  | 
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| 155 | * Validates that all characters of the value are decimal digits.  | 
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| 156 | *  | 
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| 157 | * @return $this  | 
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| 158 | */  | 
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| 159 | 4 | public function digits()  | 
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| 163 | |||
| 164 | /**  | 
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| 165 | * Validates a value to be a nested array, which can then be validated using a new Validator instance.  | 
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| 166 | *  | 
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| 167 | * @param callable $callback  | 
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| 168 | * @return $this  | 
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| 169 | */  | 
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| 170 | 5 | public function each(callable $callback)  | 
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| 174 | |||
| 175 | /**  | 
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| 176 | * Validates that the value is a valid email address (format only).  | 
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| 177 | * @return $this  | 
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| 178 | */  | 
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| 179 | 6 | public function email()  | 
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| 183 | |||
| 184 | /**  | 
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| 185 | * Validates that the value is equal to $value.  | 
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| 186 | *  | 
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| 187 | * @param string $value  | 
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| 188 | * @return $this  | 
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| 189 | */  | 
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| 190 | 2 | public function equals($value)  | 
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| 194 | |||
| 195 | /**  | 
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| 196 | * Validates that the value represents a float.  | 
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| 197 | *  | 
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| 198 | * @return $this  | 
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| 199 | */  | 
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| 200 | 6 | public function float()  | 
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| 204 | |||
| 205 | /**  | 
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| 206 | * Validates that the value is greater than $value.  | 
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| 207 | *  | 
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| 208 | * @param int $value  | 
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| 209 | * @return $this  | 
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| 210 | */  | 
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| 211 | 3 | public function greaterThan($value)  | 
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| 212 |     { | 
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| 213 | 3 | return $this->addRule(new Rule\GreaterThan($value));  | 
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| 214 | }  | 
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| 215 | |||
| 216 | /**  | 
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| 217 | * Validates that the value is in the array with optional "loose" checking.  | 
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| 218 | *  | 
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| 219 | * @param array $array  | 
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| 220 | * @param bool $strict  | 
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| 221 | * @return $this  | 
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| 222 | */  | 
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| 223 | 4 | public function inArray(array $array, $strict = true)  | 
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| 224 |     { | 
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| 225 | 4 | return $this->addRule(new Rule\InArray($array, $strict));  | 
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| 226 | }  | 
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| 227 | |||
| 228 | /**  | 
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| 229 | * Validates the value represents a valid integer  | 
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| 230 | *  | 
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| 231 | * @param bool $strict  | 
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| 232 | * @return $this  | 
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| 233 | * @see \Particle\Validator\Rule\Integer  | 
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| 234 | */  | 
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| 235 | 18 | public function integer($strict = false)  | 
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| 239 | |||
| 240 | /**  | 
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| 241 | * Validates the value is an array  | 
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| 242 | *  | 
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| 243 | * @return $this  | 
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| 244 | * @see \Particle\Validator\Rule\IsArray  | 
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| 245 | */  | 
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| 246 | 7 | public function isArray()  | 
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| 250 | |||
| 251 | /**  | 
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| 252 | * Validates that the value represents a valid JSON string  | 
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| 253 | *  | 
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| 254 | * @return $this  | 
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| 255 | * @see \Particle\Validator\Rule\Json  | 
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| 256 | */  | 
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| 257 | 11 | public function json()  | 
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| 261 | |||
| 262 | /**  | 
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| 263 | * Validate the value to be of precisely length $length.  | 
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| 264 | *  | 
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| 265 | * @param int $length  | 
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| 266 | * @return $this  | 
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| 267 | */  | 
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| 268 | 13 | public function length($length)  | 
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| 269 |     { | 
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| 270 | 13 | return $this->addRule(new Rule\Length($length));  | 
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| 271 | }  | 
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| 272 | |||
| 273 | /**  | 
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| 274 | * Validates that the length of the value is between $min and $max.  | 
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| 275 | *  | 
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| 276 | * If $max is null, it has no upper limit. The default is inclusive.  | 
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| 277 | *  | 
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| 278 | * @param int $min  | 
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| 279 | * @param int|null $max  | 
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| 280 | * @return $this  | 
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| 281 | */  | 
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| 282 | 7 | public function lengthBetween($min, $max)  | 
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| 286 | |||
| 287 | /**  | 
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| 288 | * Validates that the value is less than $value.  | 
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| 289 | *  | 
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| 290 | * @param int $value  | 
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| 291 | * @return $this  | 
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| 292 | */  | 
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| 293 | 3 | public function lessThan($value)  | 
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| 297 | |||
| 298 | /**  | 
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| 299 | * Mount a rule object onto this chain.  | 
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| 300 | *  | 
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| 301 | * @param Rule $rule  | 
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| 302 | * @return $this  | 
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| 303 | */  | 
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| 304 | 1 | public function mount(Rule $rule)  | 
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| 308 | |||
| 309 | /**  | 
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| 310 | * Validates that the value is either a integer or a float.  | 
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| 311 | *  | 
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| 312 | * @return $this  | 
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| 313 | */  | 
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| 314 | 11 | public function numeric()  | 
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| 315 |     { | 
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| 316 | 11 | return $this->addRule(new Rule\Numeric());  | 
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| 317 | }  | 
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| 318 | |||
| 319 | /**  | 
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| 320 | * Validates that the value is a valid phone number for $countryCode.  | 
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| 321 | *  | 
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| 322 | * @param string $countryCode  | 
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| 323 | * @see \Particle\Validator\Rule\Phone  | 
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| 324 | * @return $this  | 
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| 325 | */  | 
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| 326 | 13 | public function phone($countryCode)  | 
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| 330 | |||
| 331 | /**  | 
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| 332 | * Validates that the value matches the regular expression $regex.  | 
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| 333 | *  | 
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| 334 | * @param string $regex  | 
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| 335 | * @return $this  | 
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| 336 | */  | 
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| 337 | 2 | public function regex($regex)  | 
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| 341 | |||
| 342 | /**  | 
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| 343 | * Validates that the value represents a string.  | 
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| 344 | *  | 
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| 345 | * @return $this  | 
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| 346 | */  | 
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| 347 | 5 | public function string()  | 
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| 351 | |||
| 352 | /**  | 
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| 353 | * Validates that the value is a valid URL. The schemes array is to selectively whitelist URL schemes.  | 
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| 354 | *  | 
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| 355 | * @param array $schemes  | 
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| 356 | * @return $this  | 
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| 357 | */  | 
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| 358 | 7 | public function url(array $schemes = [])  | 
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| 362 | |||
| 363 | /**  | 
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| 364 | * Validates that the value is a valid UUID  | 
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| 365 | *  | 
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| 366 | * @param int $version  | 
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| 367 | * @return $this  | 
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| 368 | */  | 
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| 369 | 12 | public function uuid($version = Rule\Uuid::UUID_V4)  | 
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| 370 |     { | 
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| 371 | 12 | return $this->addRule(new Rule\Uuid($version));  | 
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| 372 | }  | 
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| 373 | |||
| 374 | /**  | 
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| 375 | * Set a callable or boolean value which may be used to alter the required requirement on validation time.  | 
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| 376 | *  | 
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| 377 | * This may be incredibly helpful when doing conditional validation.  | 
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| 378 | *  | 
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| 379 | * @param callable|bool $required  | 
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| 380 | * @return $this  | 
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| 381 | */  | 
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| 382 | 5 | public function required($required)  | 
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| 383 |     { | 
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| 384 | 5 | $this->getRequiredRule()->setRequired($required);  | 
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| 385 | 5 | return $this;  | 
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| 386 | }  | 
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| 387 | |||
| 388 | /**  | 
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| 389 | * Set a callable or boolean value which may be used to alter the allow empty requirement on validation time.  | 
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| 390 | *  | 
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| 391 | * This may be incredibly helpful when doing conditional validation.  | 
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| 392 | *  | 
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| 393 | * @param callable|bool $allowEmpty  | 
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| 394 | * @return $this  | 
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| 395 | */  | 
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| 396 | 11 | public function allowEmpty($allowEmpty)  | 
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| 397 |     { | 
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| 398 | 11 | $this->getNotEmptyRule()->setAllowEmpty($allowEmpty);  | 
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| 399 | 11 | return $this;  | 
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| 400 | }  | 
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| 401 | |||
| 402 | /**  | 
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| 403 | * Attach a representation of this Chain to the Output\Structure $structure.  | 
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| 404 | *  | 
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| 405 | * @internal  | 
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| 406 | * @param Structure $structure  | 
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| 407 | * @param MessageStack $messageStack  | 
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| 408 | * @return Structure  | 
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| 409 | */  | 
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| 410 | 2 | public function output(Structure $structure, MessageStack $messageStack)  | 
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| 411 |     { | 
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| 412 | 2 | $subject = new Subject($this->key, $this->name);  | 
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| 413 | |||
| 414 | 2 |         foreach ($this->rules as $rule) { | 
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| 415 | 2 | $rule->output($subject, $messageStack);  | 
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| 416 | 2 | }  | 
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| 417 | |||
| 418 | 2 | $structure->addSubject($subject);  | 
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| 419 | |||
| 420 | 2 | return $structure;  | 
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| 421 | }  | 
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| 422 | |||
| 423 | /**  | 
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| 424 | * Validates the values in the $values array and appends messages to $messageStack. Returns the result as a bool.  | 
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| 425 | *  | 
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| 426 | * @param MessageStack $messageStack  | 
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| 427 | * @param Container $input  | 
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| 428 | * @param Container $output  | 
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| 429 | * @return bool  | 
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| 430 | */  | 
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| 431 | 204 | public function validate(MessageStack $messageStack, Container $input, Container $output)  | 
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| 432 |     { | 
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| 433 | 204 | $valid = true;  | 
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| 434 | 204 |         foreach ($this->rules as $rule) { | 
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| 435 | 204 | $rule->setMessageStack($messageStack);  | 
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| 436 | 204 | $rule->setParameters($this->key, $this->name);  | 
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| 437 | |||
| 438 | 204 | $valid = $rule->isValid($this->key, $input) && $valid;  | 
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| 439 | |||
| 440 | 204 |             if ($rule->shouldBreakChain()) { | 
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| 441 | 17 | break;  | 
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| 442 | }  | 
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| 443 | 204 | }  | 
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| 444 | |||
| 445 | 204 |         if ($valid && $input->has($this->key)) { | 
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| 446 | 104 | $output->set($this->key, $input->get($this->key));  | 
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| 447 | 104 | }  | 
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| 448 | 204 | return $valid;  | 
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| 449 | }  | 
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| 450 | |||
| 451 | /**  | 
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| 452 | * Shortcut method for storing a rule on this chain, and returning the chain.  | 
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| 453 | *  | 
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| 454 | * @param Rule $rule  | 
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| 455 | * @return $this  | 
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| 456 | */  | 
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| 457 | 207 | protected function addRule(Rule $rule)  | 
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| 458 |     { | 
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| 459 | 207 | $this->rules[] = $rule;  | 
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| 460 | |||
| 461 | 207 | return $this;  | 
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| 462 | }  | 
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| 463 | |||
| 464 | /**  | 
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| 465 | * Returns the first rule, which is always the required rule.  | 
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| 466 | *  | 
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| 467 | * @return Rule\Required  | 
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| 468 | */  | 
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| 469 | 5 | protected function getRequiredRule()  | 
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| 473 | |||
| 474 | /**  | 
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| 475 | * Returns the second rule, which is always the allow empty rule.  | 
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| 476 | *  | 
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| 477 | * @return Rule\NotEmpty  | 
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| 478 | */  | 
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| 479 | 11 | protected function getNotEmptyRule()  | 
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| 483 | }  | 
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| 484 |