@Override
    public int compareTo(SubscriptionData other) {
        String thisValue = this.topic + "@" + this.subString;
        String otherValue = other.topic + "@" + other.subString;
        return thisValue.compareTo(otherValue);
    }
@Test
    public void testCompareTo() {
        SubscriptionData subscriptionData = new SubscriptionData("TOPICA", "*");
        SubscriptionData subscriptionData1 = new SubscriptionData("TOPICBA", "*");
        assertThat(subscriptionData.compareTo(subscriptionData1)).isEqualTo("TOPICA@*".compareTo("TOPICB@*"));
    }