private boolean equalsOrNull(Object a, Object b) {
            return (a != null)
                    ? a.equals(b)
                    : ((b == null)
                            ? true
                            : false);
        }
Set the last value.

@param lastValue the last value
@see #getLastValue()
stroom-core-client/src/main/java/stroom/dashboard/client/table/FilterCell.java