Sulu\Component\Rest\ListBuilder\Doctrine\DoctrineListBuilder::getUniqueExpressionFieldDescriptors PHP Method

    protected function getUniqueExpressionFieldDescriptors(array $expressions)
    {
        if (count($this->expressionFields) === 0) {
            $descriptors = [];
            $uniqueNames = array_unique($this->getAllFieldNames($expressions));
            foreach ($uniqueNames as $uniqueName) {
                $descriptors[] = $this->fieldDescriptors[$uniqueName];
            }
            $this->expressionFields = $descriptors;
            return $descriptors;
        }
        return $this->expressionFields;
    }