Enum in php

Enum.php

<?php

abstract class Enum
{
	/**
	 * @var array
	 */
    private static $constCacheArray = null;

	/**
	 * Get constants
	 *
	 * @return array
	 */
	private static function getConstants()
	{
		if (self::$constCacheArray == null) {
			self::$constCacheArray = [];
		}

		$calledClass = get_called_class();
		if (!array_key_exists($calledClass, self::$constCacheArray)) {
			$reflect = new ReflectionClass($calledClass);
			self::$constCacheArray[$calledClass] = $reflect->getConstants();
		}
		return self::$constCacheArray[$calledClass];
    }

	/**
	 * Check name valid
	 *
	 * @param string $name
	 * @param boolean $strict
	 * @return boolean
	 */
	public static function isValidName(string $name, bool $strict = false)
	{
		$constants = self::getConstants();

		if ($strict) {
			return array_key_exists($name, $constants);
		}

		$keys = array_map('strtolower', array_keys($constants));
		return in_array(strtolower($name), $keys);
    }

	/**
	 * Check value valid
	 *
	 * @param mixed $value
	 * @param boolean $strict
	 * @return boolean
	 */
	public static function isValidValue($value, bool $strict = true)
	{
		$values = array_values(self::getConstants());
		return in_array($value, $values, $strict);
	}
}

class DaysOfWeek extends Enum
{
	const Sunday = 0;
	const Monday = 1;
	const Tuesday = 2;
	const Wednesday = 3;
	const Thursday = 4;
	const Friday = 5;
	const Saturday = 6;
}

var_dump(
	DaysOfWeek::isValidName('Humpday'),
	DaysOfWeek::isValidName('Monday'),
	DaysOfWeek::isValidName('monday'),
	DaysOfWeek::isValidName('monday', true),
	DaysOfWeek::isValidName(0),
	DaysOfWeek::isValidValue(0),
	DaysOfWeek::isValidValue(5),
	DaysOfWeek::isValidValue(7),
	DaysOfWeek::isValidValue('Friday')
);