Grails databinding - How to exclude child property - grails

Question

How can I exclude the child domain property when I use the grailsWebDataBinder?
For example, I have domains:
class Car {
String carPropertyToExclude
Set<Detail> details
static hasMany = [details: Detail]
}
class Detail {
String detailPropertyToExclude
static belongsTo= [car: Car]
}
I want to exclude the detailPropertyToExclude from Detail when I call the bind method of grailsWebDataBinder and give the car instance as a parameter
Code:
List blackList = ["carPropertyToExclude"]
grailsWebDataBinder.bind(car, new SimpleMapDataBindingSource(params), null, blackList)
Note:
Don't suggest the bindable: false or variants when excluded from anywhere. Only need to know is there a way to do it by providing blackList as bind() method parameter.
These variants also not working:
List blackList = ["carPropertyToExclude", "details.detailPropertyToExclude"]
List blackList = ["carPropertyToExclude", [Detail.class : "detailPropertyToExclude"]]
The main question is how to prepare the blackList to exclude also child's property?

Answer 1

blacklist parameter supports only direct object properties
you can use DataBindingListener
import grails.databinding.events.DataBindingListenerAdapter
class BlackListener extends DataBindingListenerAdapter{
List<String> list
//returns false if you want to exclude property from binding
public Boolean beforeBinding(Object obj, String propertyName, Object value, Object errors) {
return !list.contains("${obj?.class.name}.${propertyName}".toString())
}
}
...
List blackList = ["Car.carPropertyToExclude", "Details.detailPropertyToExclude"]
grailsWebDataBinder.bind(car, new SimpleMapDataBindingSource(params),
new BlackListener(list:blackList) )
UPD:
Unfortunately the method above does not work with Collection binding.
The problem that SimpleDataBinder.setPropertyValue(...) method loses listener when processing a list.
Not sure if following workaround is good (potentially context initialization required)
but it's possible to register converter for each black list:
import grails.databinding.SimpleDataBinder
import grails.databinding.SimpleMapDataBindingSource
import grails.databinding.converters.ValueConverter
SimpleDataBinder setBlackList(SimpleDataBinder binder, Map<Class,List<String>> blackLists) {
blackLists.each { Class clazz, List<String> blackList ->
def vc = new ValueConverter(){
boolean canConvert(Object value){
return value instanceof Map
}
Object convert(Object value){
def obj = clazz.newInstance()
binder.bind( obj, new SimpleMapDataBindingSource(value), [], blackList )
return obj
}
Class<?> getTargetType(){ clazz }
}
binder.registerConverter(vc)
}
return binder
}
...
Map blackLists = [
(Car.class) : ["carPropertyToExclude"],
(Detail.class) : ["detailPropertyToExclude"]
]
setBlackList(grailsWebDataBinder,blackLists)
...
grailsWebDataBinder.bind(car, new SimpleMapDataBindingSource(params), null,
blackLists[car.getClass()] )
PS: as alternative possible to set grailsWebDataBinder.conversionService...

Answer 2

In a controller you can exclude props from binding by:
def someAction(){
Car car = new Car()
bindData car, params, [exclude: ['carPropertyToExclude', 'details']]
car.details = params.list('details').collect{
bindData new Detail(), [exclude: ['detailPropertyToExclude']]
}
}
You might also want to use the command-objects to represent your form-data.

Answer 3

I have found one solution based on daggett answer. Maybe in greater versions, the bug is fixed or will be fixed. The bug is that when we give the listener as a parameter of bind method for child domains the listener isn't triggered but when we set it as class level listener works. Grails version 3.2.11.
I have created the BlackListener like this:
public class BlackListListener extends DataBindingListenerAdapter {
private final Map<Class<?>, Collection<String>> blackList;
public BlackListListener(Map<Class<?>, Collection<String>> blackList) {
this.blackList = blackList;
}
public Boolean beforeBinding(Object obj, String propertyName, Object value, Object errors) {
Boolean result = Boolean.TRUE;
Collection<String> list = blackList.get(obj.getClass());
if (CollectionUtils.isNotEmpty(list)) {
result = !list.contains(propertyName);
}
return result;
}
}
Then I make my own grailsWebDatabinder bean as prototype:
<bean id="webDataBinder" class="grails.web.databinding.GrailsWebDataBinder" c:_0-ref="grailsApplication"
scope="prototype"/>
<bean id="carBinder" class="CarDataBinder" c:_0-ref="webDataBinder"/>
and then when I want to use data binder I inject the webDataBinder and init listener:
public CarDataBinder(GrailsWebDataBinder grailsWebDataBinder) {
this.grailsWebDataBinder = grailsWebDataBinder;
DataBindingListener blackListListener = new BlackListListener(
ImmutableMap.of(
Car.class, ImmutableSet.of("carPropertyToExclude"),
Detail.class, ImmutableSet.of("detailPropertyToExclude")
)
);
grailsWebDataBinder.setDataBindingListeners(blackListListener);
}
and then:
void bindData(Car car, Map<?, ?> params) {
grailsWebDataBinder.bind(car, new SimpleMapDataBindingSource(params));
}
If there are better ways you can post.