Grails : Overriding getter method in domain class - grails

Question

I can't override grails getter method and becoming crazy.
What I want is use a double value and a string value to get a formatted data, but when I'm typing my override method into String, the double value is null and when into double, it obviously get me an error because a String is returned !
I get a domain class like that :
class Project {
...
String currency
Double initialTargetAmount
...
}
First Override method (initialTargetAmount is null in this case) :
//#Override Comment or uncomment it does not make any change to the behaviour
public String getInitialTargetAmount() {
println "${initialTargetAmount} ${currency}" // display "null EUR"
"${initialTargetAmount} ${currency}" // initialTargetAmount is null
}
Second method :
//#Override Comment or uncomment it does not make any change to the behaviour
public Double getInitialTargetAmount() {
println "${initialTargetAmount} ${currency}" // display "1000.00 EUR"
"${initialTargetAmount} ${currency}" // Error : String given, Double expected
}
Any help is welcome.
Snite

Answer 1

Groovy has dynamic getters and setters.
So, initalTargetAmount field "creates" automatically a Double getInitialTargetAmount method. Which is why it works when you have the Double return Type. But when you set String, getInitialTargetAmount automatically refers to a field String initalTargetAmount which doesn't exist
Try changing the name of the method, for example getInitialAmountWithCurrency() and it will work. Maybe your best bet will be to override toString() method ^^

Answer 2

Your getter should be always the same type of your field, and it's noot a good approach to change the getter like this, because Grails (Hibernate internally) will understand that your object instance changed and will try to update it ( it will check the old and new values).
You're trying in fact is to have a String representation of your amount, so you have a couple of options to this:
1 - A new method
Creating a new method that returns String will not interfere in the hibernate flow and you can use it anywere.
class Project {
...
String currency
Double initialTargetAmount
...
String displayTargetAmount() {
"${initialTargetAmount} ${currency}"
}
}
2 - TagLib
Depending on your needs, you could create a TagLib to make this custom representations of your class. This can include html formatting.
class ProjectTagLib {
static namespace = "proj"
def displayAmount = { attrs ->
if(!attrs.project) {
throwTagErrro("Attribute project must be defined.")
}
Project project = attrs.remove('project')
//just an example of html
out << "<p>${project.initialTargetAmount} , ${project.currency}</p>"
}
}