Grails 3: using findAll with join tables - sql

Question

In my Grails webapp I have the following domain classes:
class Customer {
static hasMany = [
addresses: Address
]
static mapping = {
addresses (cascade: "all-delete-orphan", joinTable: [name: "bs_core_customer_addresses"])
}
}
class Address {
...
}
Now I want to implement the abillity to filter the 1:n relation like addresses for things like country (should be dynamic, that means the user can add different filters by itself).
What is the best way to accomplish this?
Filtering the collection from the Customer object? e.g. customer.addresses.findAll{...}
Direct query from the database? How can I add the restriction for the Customer<->Address relation. belongsTo at the Address domain class is no option because the Address object is used in several 1:n relations. e.g. Customer.findAll(...)
Any other option?

Answer 1

you should be able to get away with
static constraints = {
addresses(validator: checkAddress)
}
// This is a static method which is used for validation
// and can be used for when inserting a record to check how many
// existing addresses exist for the end user that has countryCode of US
// This is directly bound to all the object the user and will
// will not be searching the entire DB (A local find limited to user records)
static def checkAddress={val,obj,errors->
if (!obj?.addresses.findAll{it.countryCode=='US'}?.size() >= 2) {
return errors.rejectValue('adress','exceeds limit')
}
}
The above should be self explanatory, but having read through your post a few times now I think I have a better understanding of what you are trying to achieve and there are probably a few different ways of doing it. So let's explore some of them:
Using HQL query, you could change this to another method, I prefer HQL.
class Customer {
def userService
//UserAddress does not have setter transients not essential
static transients = ['userAddress','userService']
//This is a protected function that will return an address
// object given a countryCode
// Execute like this:
// Customer cm = Customer.get(customer.id as Long)
//Address usa = cm.getCountry('US')
protected Address getUserAddress(String countryCode) {
return userService.findAddress(countryCode, this.id)
}
}
Now the service but actually you don't need to execute in domain class unless there is some other need, for displaying etc you could always call this sort of service from within a controller call to render for display purposes
class UserSerice {
// This should return the entire address object back to the domain class
// that called it and will be quicker more efficient than findAll
Address findAddress(String countryCode, Long customerId) {
String query="""
select address from Address a
where a.id :id and countryCode = :code
"""
def inputParams=[code:countryCode, id:customerId]
return Address.executeQuery(query,inputParams,[readOnly:true,timeout:15])
}
Another approach could be a 3rd table that gets updated upon each address added that would give a quick lookup:
class Customer {
static hasMany = [
addresses: Address
//probably don't even need this
//, userCountries:UserCountries
]
}
Class UserCountries {
// register customer
Customer customer
String CountryCode
//maybe address object or Long addressId - depending on if how plain you wanted this to be
Address address
}
Then register the address id and countryCode to this domainclass each time you add a new address and I guess you would need to write some backward compatible code to add existing records to this table for it to work properly.
I left a comment and then removed it for you to expand further on what or how the filtering was taking place. since although you talk of countryCode there is no actual code to show how it all fits in.
I still think something as simple as this would work
//This would only be doing a find with all the bound objects of addresses bound to this customer. so a find within the hasMany relationship elements of this specific customer
protected def getCustomAddress(String countryCode) {
return addresses.findAll{it.code==countryCode}
}
Other far out ideas could be something like this
class Customer {
String _bindAddress
List bindAddress=[]
static transients = [ 'bindAddress' ]
static constraints = {
_bindAddress(nullable:true)
}
//you store a flat CSV as _bindAddress
//you need to work out your own logic to ammend to existing CSV each time address is added
// you will also update _bindAddress of this domainClass each time customer gets a hasMany address added
// so no need for setBindAddress
// void setBindAddress(String b) {
// bindAddress=b.split(',')
// }
//Inorder to set a list back to flat file
//pass in list object
void setBindAddress(List bindAddress) {
_bindAddress=bindAddress.join(',')
/for 1 element this captures better
//_bindAddress=bindAddress.tokenize(',').collect{it}
}
//This is now your object as a list that you can query for what you are querying.
List getBindAdress() {
return _bindAddress.split(',')
}
}
If your actual csv list contained a listing of 'COUNTRY_CODE-ADDRESS_ID' then you could query like this
def found = customer.bindAddress.find{it.startsWith('US-')}
Address usaAddress= Address.get(found.split('-')[1] as Long)
//Slightly longer explaining above:
def found = customer.bindAddress.find{it.startsWith('US-')}
def record = found.split('-')
String countryCode=record[0]
Long addressId=record[1] as Long
Address usaAddress= Address.get(addressId)