State::getPossibleTransitionsMap

protected function getPossibleTransitionsMap(): array
{
	static $map = null;
	
	if ($map === null)
	{
		$map = [
			static::STATE_UNDEFINED => [
				static::STATE_FREE => true,
				static::STATE_ASSIGNED => true,
			],
			static::STATE_FREE => [
				static::STATE_ASSIGNED => true,
			],
			static::STATE_ASSIGNED => [
				static::STATE_FREE => true,
				static::STATE_INDEX => true,
			],
			static::STATE_INDEX => [
				static::STATE_FREE => true,
				static::STATE_ERROR => true,
				static::STATE_READY => true,
			],
			static::STATE_ERROR => [
				static::STATE_FREE => true,
				static::STATE_ASSIGNED => true,
			],
			static::STATE_READY => [
				static::STATE_FREE => true,
				static::STATE_ASSIGNED => true,
				static::STATE_INDEX => true,
			],
		];
	}
	
	return $map;
}