Converted returned null and null checks to Optional

moquette-io · Jun 19, 2023 · c24d92b · c24d92b
1 parent a8d102e
commit c24d92b
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Showing 3 changed files with 28 additions and 24 deletions.
diff --git a/broker/src/main/java/io/moquette/broker/subscriptions/CNode.java b/broker/src/main/java/io/moquette/broker/subscriptions/CNode.java
@@ -44,12 +44,12 @@ List<INode> allChildren() {
         return new ArrayList<>(this.children);
     }
 
-    INode childOf(Token token) {
+    Optional<INode> childOf(Token token) {
         int idx = findIndexForToken(token);
         if (idx < 0) {
-            return null;
+            return Optional.empty();
         }
-        return children.get(idx);
+        return Optional.of(children.get(idx));
     }
 
     private int findIndexForToken(Token token) {

diff --git a/broker/src/main/java/io/moquette/broker/subscriptions/CTrie.java b/broker/src/main/java/io/moquette/broker/subscriptions/CTrie.java
@@ -32,12 +32,12 @@ Optional<CNode> lookup(Topic topic) {
         INode inode = this.root;
         Token token = topic.headToken();
         while (!topic.isEmpty()) {
-            INode child = inode.mainNode().childOf(token);
-            if (child == null) {
+            Optional<INode> child = inode.mainNode().childOf(token);
+            if (child.isEmpty()) {
                 break;
             }
             topic = topic.exceptHeadToken();
-            inode = inode.mainNode().childOf(token);
+            inode = child.get();
             token = topic.headToken();
         }
         if (inode == null || !topic.isEmpty()) {
@@ -85,20 +85,20 @@ private Set<Subscription> recursiveMatch(Topic topic, INode inode) {
 
         // We should only consider the maximum three children children of
         // type #, + or exact match
-        INode subInode = cnode.childOf(Token.MULTI);
-        if (subInode != null) {
-            subscriptions.addAll(recursiveMatch(remainingTopic, subInode));
+        Optional<INode> subInode = cnode.childOf(Token.MULTI);
+        if (subInode.isPresent()) {
+            subscriptions.addAll(recursiveMatch(remainingTopic, subInode.get()));
         }
         subInode = cnode.childOf(Token.SINGLE);
-        if (subInode != null) {
-            subscriptions.addAll(recursiveMatch(remainingTopic, subInode));
+        if (subInode.isPresent()) {
+            subscriptions.addAll(recursiveMatch(remainingTopic, subInode.get()));
         }
         if (remainingTopic.isEmpty()) {
             subscriptions.addAll(cnode.subscriptions);
         } else {
             subInode = cnode.childOf(remainingTopic.headToken());
-            if (subInode != null) {
-                subscriptions.addAll(recursiveMatch(remainingTopic, subInode));
+            if (subInode.isPresent()) {
+                subscriptions.addAll(recursiveMatch(remainingTopic, subInode.get()));
             }
         }
         return subscriptions;
@@ -115,10 +115,10 @@ private Action insert(Topic topic, final INode inode, Subscription newSubscripti
         final Token token = topic.headToken();
         final CNode cnode = inode.mainNode();
         if (!topic.isEmpty()) {
-            INode nextInode = cnode.childOf(token);
-            if (nextInode != null) {
+            Optional<INode> nextInode = cnode.childOf(token);
+            if (nextInode.isPresent()) {
                 Topic remainingTopic = topic.exceptHeadToken();
-                return insert(remainingTopic, nextInode, newSubscription);
+                return insert(remainingTopic, nextInode.get(), newSubscription);
             }
         }
         if (topic.isEmpty()) {
@@ -130,21 +130,23 @@ private Action insert(Topic topic, final INode inode, Subscription newSubscripti
 
     private Action insertSubscription(INode inode, CNode cnode, Subscription newSubscription) {
         final CNode updatedCnode;
-        if (cnode instanceof TNode)
+        if (cnode instanceof TNode) {
             updatedCnode = new CNode(cnode.getToken());
-        else
+        } else {
             updatedCnode = cnode.copy();
+        }
         updatedCnode.addSubscription(newSubscription);
         return inode.compareAndSet(cnode, updatedCnode) ? Action.OK : Action.REPEAT;
     }
 
     private Action createNodeAndInsertSubscription(Topic topic, INode inode, CNode cnode, Subscription newSubscription) {
         final INode newInode = createPathRec(topic, newSubscription);
         final CNode updatedCnode;
-        if (cnode instanceof TNode)
+        if (cnode instanceof TNode) {
             updatedCnode = new CNode(cnode.getToken());
-        else
+        } else {
             updatedCnode = cnode.copy();
+        }
         updatedCnode.add(newInode);
 
         return inode.compareAndSet(cnode, updatedCnode) ? Action.OK : Action.REPEAT;
@@ -180,10 +182,10 @@ private Action remove(String clientId, Topic topic, INode inode, INode iParent)
         Token token = topic.headToken();
         final CNode cnode = inode.mainNode();
         if (!topic.isEmpty()) {
-            INode nextInode = cnode.childOf(token);
-            if (nextInode != null) {
+            Optional<INode> nextInode = cnode.childOf(token);
+            if (nextInode.isPresent()) {
                 Topic remainingTopic = topic.exceptHeadToken();
-                return remove(clientId, remainingTopic, nextInode, inode);
+                return remove(clientId, remainingTopic, nextInode.get(), inode);
             }
         }
         if (cnode instanceof TNode) {

diff --git a/broker/src/main/java/io/moquette/broker/subscriptions/TNode.java b/broker/src/main/java/io/moquette/broker/subscriptions/TNode.java
@@ -15,14 +15,16 @@
  */
 package io.moquette.broker.subscriptions;
 
+import java.util.Optional;
+
 class TNode extends CNode {
 
     public TNode(Token token) {
         super(token);
     }
 
     @Override
-    INode childOf(Token token) {
+    Optional<INode> childOf(Token token) {
         throw new IllegalStateException("Can't be invoked on TNode");
     }