Refact: introduce explicit empty class for TypeCheckCache

ballerina-platform · Jun 24, 2024 · 9ebdb7d · 9ebdb7d
1 parent 8dc1f34
commit 9ebdb7d
Showing 1 changed file with 18 additions and 4 deletions.
diff --git a/bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/api/types/semtype/SemType.java b/bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/api/types/semtype/SemType.java
@@ -56,7 +56,7 @@ protected SemType(int all, int some, SubType[] subTypeData) {
             this.resultCache = new TypeCheckResultCache();
         } else {
             useCache = false;
-            this.resultCache = null;
+            this.resultCache = TypeCheckResultCache.EMPTY;
         }
     }
 
@@ -151,17 +151,18 @@ void cacheSubTypeRelation(SemType other, boolean result) {
         }
     }
 
-    private static final class TypeCheckResultCache {
+    private static sealed class TypeCheckResultCache {
 
+        private static final TypeCheckResultCache EMPTY = new EmptyTypeCheckResultCache();
         private static final int CACHE_LIMIT = 100;
         // See if we can use an identity hashmap on semtypes instead of tid
         private Map<Long, Boolean> cache = new HashMap<>();
 
-        private void cacheResult(int tid, boolean result) {
+        protected void cacheResult(int tid, boolean result) {
             cache.put((long) tid, result);
         }
 
-        private CachedResult getCachedResult(int tid) {
+        protected CachedResult getCachedResult(int tid) {
             Boolean cachedData = cache.get((long) tid);
             if (cachedData == null) {
                 return CachedResult.NOT_FOUND;
@@ -170,6 +171,19 @@ private CachedResult getCachedResult(int tid) {
         }
     }
 
+    private static final class EmptyTypeCheckResultCache extends TypeCheckResultCache {
+
+        @Override
+        public void cacheResult(int tid, boolean result) {
+            throw new UnsupportedOperationException("Empty cache");
+        }
+
+        @Override
+        public CachedResult getCachedResult(int tid) {
+            throw new UnsupportedOperationException("Empty cache");
+        }
+    }
+
     public final SubType subTypeByCode(int code) {
         if ((some() & (1 << code)) == 0) {
             return null;