[broker-30] Improve code readability

Author: crazyrokr

application/src/main/java/javasabr/mqtt/broker/application/config/MqttBrokerSpringConfig.java

@@ -95,8 +95,7 @@ CredentialSource credentialSource(
   @Bean
   AuthenticationService authenticationService(
       CredentialSource credentialSource,
-      @Value("${authentication.allow.anonymous:false}")
-      boolean allowAnonymousAuth) {
+      @Value("${authentication.allow.anonymous:false}") boolean allowAnonymousAuth) {
     return new SimpleAuthenticationService(credentialSource, allowAnonymousAuth);
   }
 

core-service/src/main/java/javasabr/mqtt/service/impl/InMemorySubscriptionService.java

@@ -8,6 +8,7 @@
 import javasabr.mqtt.model.MqttClientConnectionConfig;
 import javasabr.mqtt.model.MqttUser;
 import javasabr.mqtt.model.QoS;
+import javasabr.mqtt.model.SubscribeRetainHandling;
 import javasabr.mqtt.model.reason.code.SubscribeAckReasonCode;
 import javasabr.mqtt.model.reason.code.UnsubscribeAckReasonCode;
 import javasabr.mqtt.model.session.ActiveSubscriptions;
@@ -83,8 +84,10 @@ private SubscribeAckReasonCode addSubscription(MqttUser user, MqttSession sessio
       activeSubscriptions.remove(previous.subscription());
     }
     QoS subscriptionQoS = subscription.qos();
-    if (subscriptionQoS.ordinal() <= 2 && (subscription.retainHandling() == SEND || (
-        subscription.retainHandling() == SEND_IF_SUBSCRIPTION_DOES_NOT_EXIST && previous == null))) {
+    SubscribeRetainHandling retainHandling = subscription.retainHandling();
+    boolean isRetainHandlingSatisfied =
+        retainHandling == SEND || (retainHandling == SEND_IF_SUBSCRIPTION_DOES_NOT_EXIST && previous == null);
+    if (subscriptionQoS.isValid() && isRetainHandlingSatisfied) {
       sendRetainedMessages(user, subscription);
     }
     activeSubscriptions.add(subscription);

model/src/main/java/javasabr/mqtt/model/QoS.java

@@ -19,8 +19,7 @@ public enum QoS implements NumberedEnum<QoS> {
   EXACTLY_ONCE(2, SubscribeAckReasonCode.GRANTED_QOS_2),
   INVALID(3, SubscribeAckReasonCode.IMPLEMENTATION_SPECIFIC_ERROR);
 
-  private static final NumberedEnumMap<QoS> NUMBERED_MAP =
-      new NumberedEnumMap<>(QoS.class);
+  private static final NumberedEnumMap<QoS> NUMBERED_MAP = new NumberedEnumMap<>(QoS.class);
 
   public static QoS ofCode(int level) {
     return NUMBERED_MAP.resolve(level, QoS.INVALID);
@@ -45,4 +44,8 @@ public boolean isLowerThan(QoS another) {
   public boolean isHigherThan(QoS another) {
     return level > another.level;
   }
+
+  public boolean isValid() {
+    return this != INVALID;
+  }
 }