criteria/common/src/org/immutables/criteria/constraints/ComparableCriteria.java
public R isLessThan(V upper) {
    return create(e -> Expressions.call(Operators.LESS_THAN, e, Expressions.literal(upper)));
  }
public R isLessThan(V upper) {
    return create(e -> Expressions.call(Operators.LESS_THAN, e, Expressions.literal(upper)));
  }
]
Checks that attribute is less than (but not equal to) {@code upper}.
<p>Use {@link #isAtMost(Comparable)} for less <i>or equal</i> comparison</p>