Constraint to check if null?

[benoitx]

Hi

I have a case where a property can be null or must be in a range.

I was thinking of using ifTrue(constraint1, constraint2)

where constraint1 would be "property is not null"...
Question how do you specify that one?

does the present() means 'not-null'?

Thanks

Benoit

[benoitx]

Allow me to be a bit more precise.

public class MyClass {
  private BigDecimal quantity;
  private BigDecimal maxQuantity;
}

I want to be able to say:
- IF quantity is not null, then quantity must be > 0 AND less or equal to maxQuantity.
- if quantity is null, no requirement for a rule.

I thought of using

new Rules(MyClass.class) {
 protected void initRules() {
  add("quantity", ifTrue( present(), 
    all(new Constraint[] { 
       required(),
       gt(new BigDecimal(0.0)),
       gteProperty("maxQuantity", "quantity") }));

However this seems to say that maxQuantity is NOT a property of BigDecimal, but I cannot figure out why it seems to call it on a BigDecimal rather than MyClass???

Could somebody enlighten me? THANKS

Benoit