filter = ff.isNull(ff.property("approved"));
// The usual array of property comparisons is supported
// the comparison is based on the kind of data so both
// numeric, date and string comparisons are supported.
filter = ff.less(ff.property("depth"), ff.literal(300));
filter = ff.lessOrEqual(ff.property("risk"), ff.literal(3.7));
filter = ff.greater(ff.property("name"), ff.literal("Smith"));
filter = ff.greaterOrEqual(ff.property("schedule"), ff.literal(new Date()));
// PropertyIsBetween is a short inclusive test between two values