Rules Chaining

Usage

Following previous section, when you call a condition to make a rule, you get back a subclass of StepCondition that can be passed to the DOOV#when method to produce a validation rule.

But some conditions returns a DefaultCondition, which cannot be passed to DOOV.when because the condition is not considered complete. This is called chaining.

For example, this code is NOT using chaining:

DOOV.when(userLastName.isNotNull()).validate();

This code is using chaining, because monthsBetween returns a NumericCondition that is not a StepCondition. Note that not calling lesserThan will result in a compilation error because the rule is not complete.

DOOV.when(accountCreationDate.monthsBetween(LocalDateSuppliers.today())
                             .lesserThan(6))
    .validate();

This is especially useful for date fields, because you can modify the value by chaining functions. You can change them a much as you want, until you call a method that returns another condition type, like yearsBetween in this example.

DOOV.when(userBirthdate.with(firstDayOfNextYear())
                       .with(ofDateAdjuster(d -> d.withDayOfMonth(15)))
                       .yearsBetween(LocalDate.now()))
                       .eq(18)
    .validate();