How can I use an if/else-statement within predicates?

Question

So I have this piece of code here:

final CriteriaBuilder builder = JPA.em().getCriteriaBuilder();
    final CriteriaQuery<Ticket> criteria = builder.createQuery(Ticket.class);
    Root<Ticket> ticketRoot = criteria.from(Ticket.class);
    Join<Ticket, Order> order = ticketRoot.join("order", JoinType.LEFT);
    Join<Ticket, EventGroup> eventGroups = ticketRoot.join("eventGroup", JoinType.LEFT);
    final List<javax.persistence.criteria.Predicate> predicates = new ArrayList<>();


if (from != null) {
    predicates.add(
        builder.or(
            builder.greaterThanOrEqualTo(order.get("completedOn"), from),
            builder.greaterThanOrEqualTo(ticketRoot.get("refundedAt"), from)
        )
    );
}

It now looks for tickets with completedOn OR refundedAt with a date after from. I want to change this.

What I want to have now is the following: If a ticket's refundedAt is not null, get refundedAt with date after from, else get completedOn with date after from.

I tried to use builder.selectCase(), also in combination with criteria.multiSelect(), but that didn't work.

I hope somebody can help me.

Edit: To make the current situation clear, this is the if/else-statement explained:

IF refundedAt is not null, get the ticket ONLY if refundedAt is after from.

ELSE (refundedAt is null) get the ticket ONLY if completedOn is after from.

Answer 1

Using and and or :

predicates.add(
    builder.or(
        builder.and(    
            builder.isNotNull(ticketRoot.get("refundedAt")),        
            builder.greaterThanOrEqualTo(ticketRoot.get("refundedAt"), from)
        ),
        builder.and(            
            builder.isNull(ticketRoot.get("refundedAt")), 
            builder.greaterThanOrEqualTo(order.get("completedOn"), from)
        )
    )
);