class CaseLogValidator < ActiveModel::Validator # Methods need to be named 'validate_' followed by field name # this is how the metaprogramming of the method name being # call in the validate method works. def validate_tenant_code(record) if record.tenant_code.blank? record.errors.add :tenant_code, "Tenant code can't be blank" end end def validate_tenant_age(record) if record.tenant_age.blank? record.errors.add :tenant_age, "Tenant age can't be blank" elsif !(record.tenant_age.to_s =~ /^[1-9][0-9]?$|^100$/) record.errors.add :tenant_age, "Tenant age must be between 0 and 100" end end def validate(record) question_to_validate = options[:previous_page] public_send("validate_#{question_to_validate}", record) end end class CaseLog < ApplicationRecord validate :instance_validations @previous_page enum status: { "in progress" => 0, "submitted" => 1 } def previous_page(value) @previous_page = value end def instance_validations validates_with CaseLogValidator, ({ previous_page: @previous_page } || {}) end end