2 files changed, 37 insertions, 36 deletions

diff --git a/store/src/main/java/org/eclipse/viatra/solver/data/model/ModelStoreImpl.java b/store/src/main/java/org/eclipse/viatra/solver/data/model/ModelStoreImpl.java
index f5e3b141..a97fb27a 100644
--- a/store/src/main/java/org/eclipse/viatra/solver/data/model/ModelStoreImpl.java
+++ b/store/src/main/java/org/eclipse/viatra/solver/data/model/ModelStoreImpl.java
@@ -1,7 +1,6 @@
 package org.eclipse.viatra.solver.data.model;
 
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
@@ -34,8 +33,7 @@ public class ModelStoreImpl implements ModelStore {
                 Map<SimilarRelationEquivalenceClass, List<Relation<?>>> symbolRepresentationsPerHashPerArity = new HashMap<>();
 
                 for (DataRepresentation<?, ?> dataRepresentation : dataRepresentations) {
-                        if (dataRepresentation instanceof Relation<?>) {
-                                Relation<?> symbolRepresentation = (Relation<?>) dataRepresentation;
+                        if (dataRepresentation instanceof Relation<?> symbolRepresentation) {
                                 addOrCreate(symbolRepresentationsPerHashPerArity,
                                                 new SimilarRelationEquivalenceClass(symbolRepresentation), symbolRepresentation);
                         } else if (dataRepresentation instanceof AuxilaryData<?, ?>) {
@@ -58,10 +56,10 @@ public class ModelStoreImpl implements ModelStore {
                         List<Relation<?>> symbolGroup) {
                 final ContinousHashProvider<Tuple> hashProvider = symbolGroup.get(0).getHashProvider();
                 final Object defaultValue = symbolGroup.get(0).getDefaultValue();
-                
+
                 List<VersionedMapStore<Tuple, Object>> maps = VersionedMapStoreImpl
                                 .createSharedVersionedMapStores(symbolGroup.size(), hashProvider, defaultValue);
-                
+
                 for (int i = 0; i < symbolGroup.size(); i++) {
                         result.put(symbolGroup.get(i), maps.get(i));
                 }
@@ -100,24 +98,20 @@ public class ModelStoreImpl implements ModelStore {
                 }
                 return new ModelImpl(this, maps);
         }
-        
+
         @Override
-        @SuppressWarnings("squid:S1751")
         public synchronized Set<Long> getStates() {
-                // if not empty, return first
-                for(VersionedMapStore<?, ?> store : stores.values()) {
-                        return new HashSet<>(store.getStates());
+                var iterator = stores.values().iterator();
+                if (iterator.hasNext()) {
+                        return Set.copyOf(iterator.next().getStates());
                 }
-                // if empty
-                Set<Long> result = new HashSet<>();
-                result.add(0l);
-                return result;
+                return Set.of(0l);
         }
 
         @Override
         public synchronized ModelDiffCursor getDiffCursor(long from, long to) {
-                Map<DataRepresentation<?, ?>,DiffCursor<?,?>> diffcursors = new HashMap<>();
-                for(Entry<DataRepresentation<?, ?>, VersionedMapStore<?, ?>> entry : stores.entrySet()) {
+                Map<DataRepresentation<?, ?>, DiffCursor<?, ?>> diffcursors = new HashMap<>();
+                for (Entry<DataRepresentation<?, ?>, VersionedMapStore<?, ?>> entry : stores.entrySet()) {
                         DataRepresentation<?, ?> representation = entry.getKey();
                         DiffCursor<?, ?> diffCursor = entry.getValue().getDiffCursor(from, to);
                         diffcursors.put(representation, diffCursor);
diff --git a/store/src/main/java/org/eclipse/viatra/solver/data/model/representation/TruthValue.java b/store/src/main/java/org/eclipse/viatra/solver/data/model/representation/TruthValue.java
index aeccde9e..049c7eac 100644
--- a/store/src/main/java/org/eclipse/viatra/solver/data/model/representation/TruthValue.java
+++ b/store/src/main/java/org/eclipse/viatra/solver/data/model/representation/TruthValue.java
@@ -1,42 +1,49 @@
 package org.eclipse.viatra.solver.data.model.representation;
 
-public class TruthValue {
-        public static final TruthValue True = new TruthValue("true");
-        public static final TruthValue False = new TruthValue("false");
-        public static final TruthValue Unknown = new TruthValue("unknown");
-        public static final TruthValue Error = new TruthValue("error");
-        
+public enum TruthValue {
+        TRUE("true"),
+
+        FALSE("false"),
+
+        UNKNOWN("unknown"),
+
+        ERROR("error");
+
         private final String name;
-        protected TruthValue(String name) {
+
+        private TruthValue(String name) {
                 this.name = name;
         }
-        
+
         public String getName() {
                 return name;
         }
-        
+
         public static TruthValue toTruthValue(boolean value) {
-                if(value) return True;
-                else return False;
+                return value ? TRUE : FALSE;
         }
+
         public boolean isConsistent() {
-                return this != Error;
+                return this != ERROR;
         }
+
         public boolean isComplete() {
-                return this != Unknown;
+                return this != UNKNOWN;
         }
+
         public boolean must() {
-                return this == True || this == Error;
+                return this == TRUE || this == ERROR;
         }
+
         public boolean may() {
-                return this == True || this == Unknown;
+                return this == TRUE || this == UNKNOWN;
         }
-        
+
         public TruthValue not() {
-                if(this == True) {
-                        return False;
-                } else if(this == False) {
-                        return True;
+                if (this == TRUE) {
+                        return FALSE;
+                } else if (this == FALSE) {
+                        return TRUE;
                 } else {
                         return this;
                 }