public function getDefaultOperatorInputByType()
    {
        if (null === $this->_defaultOperatorInputByType) {
            $this->_defaultOperatorInputByType = [
                'string'      => ['{}', '!{}'],
                'numeric'     => ['==', '!=', '>=', '>', '<=', '<'],
                'date'        => ['==', '>=', '>', '<=', '<'],
                'select'      => ['==', '!='],
                'boolean'     => ['==', '!='],
                'multiselect' => ['()', '!()'],
                'grid'        => ['()', '!()'],
                'category'    => ['()', '!()'],
            ];
            $this->_arrayInputTypes            = ['multiselect', 'grid', 'category'];
        }

        return $this->_defaultOperatorInputByType;
    }