Complex classes like FlightValidator 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 FlightValidator, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 11 | class FlightValidator extends AbstractValidator  | 
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| 12 | { | 
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| 13 | /**  | 
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| 14 | * @var Product  | 
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| 15 | */  | 
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| 16 | private $defaultService;  | 
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| 17 | |||
| 18 | /**  | 
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| 19 | * @inheritDoc  | 
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| 20 | */  | 
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| 21 | public function __construct(Translate $langs, DoliDB $db, $defaultServiceId)  | 
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| 26 | |||
| 27 | /**  | 
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| 28 |      * {@inheritdoc} | 
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| 29 | */  | 
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| 30 | public function isValid($vol, $context = [])  | 
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| 46 | |||
| 47 | /**  | 
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| 48 | * @param array $context  | 
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| 49 | *  | 
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| 50 | * @return bool  | 
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| 51 | */  | 
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| 52 | private function isGroupedFlight($context)  | 
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| 56 | |||
| 57 | /**  | 
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| 58 | * @param string $hour  | 
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| 59 | *  | 
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| 60 | * @return bool  | 
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| 61 | */  | 
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| 62 | private function isHourValid($hour)  | 
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| 67 | |||
| 68 | /**  | 
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| 69 | * @param $defaultServiceId  | 
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| 70 | */  | 
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| 71 | private function fetchService($defaultServiceId)  | 
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| 76 | |||
| 77 | /**  | 
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| 78 | * Returns the minimum price.  | 
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| 79 | *  | 
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| 80 | * @return int  | 
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| 81 | */  | 
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| 82 | private function getMinPrice()  | 
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| 89 | |||
| 90 | /**  | 
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| 91 | * @param Bbcvols $vol  | 
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| 92 | * @param array $context  | 
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| 93 | *  | 
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| 94 | * @return $this  | 
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| 95 | */  | 
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| 96 | private function checkBillingInformation($vol, $context)  | 
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| 119 | |||
| 120 | /**  | 
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| 121 | * @param Bbcvols $vol  | 
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| 122 | * @param array $context  | 
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| 123 | *  | 
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| 124 | * @return $this  | 
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| 125 | */  | 
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| 126 | private function checkInstructionInformation($vol, $context)  | 
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| 141 | |||
| 142 | /**  | 
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| 143 | * @param Bbcvols $vol  | 
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| 144 | *  | 
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| 145 | * @return $this  | 
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| 146 | */  | 
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| 147 | private function checkPassengersInformation($vol)  | 
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| 172 | |||
| 173 | /**  | 
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| 174 | * @param Bbcvols $vol  | 
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| 175 | *  | 
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| 176 | * @return $this  | 
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| 177 | */  | 
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| 178 | private function checkKilometers($vol)  | 
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| 192 | |||
| 193 | /**  | 
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| 194 | * @param Bbcvols $vol  | 
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| 195 | *  | 
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| 196 | * @return $this  | 
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| 197 | */  | 
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| 198 | private function checkFlightInformation($vol)  | 
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| 222 | }  |