[#noissue] Improve ID assignment in SimpleCache

pinpoint-apm · Sep 13, 2024 · 689a1e6 · 689a1e6
1 parent 1ccf6cb
commit 689a1e6
Showing 1 changed file with 24 additions and 15 deletions.
diff --git a/agent-module/profiler/src/main/java/com/navercorp/pinpoint/profiler/cache/SimpleCache.java b/agent-module/profiler/src/main/java/com/navercorp/pinpoint/profiler/cache/SimpleCache.java
@@ -20,13 +20,14 @@
 
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Function;
 
 /**
  * @author emeroad
  */
 public class SimpleCache<T> implements Cache<T, Result<Integer>> {
     // zero means not exist.
-    private final ConcurrentMap<T, Result<Integer>> cache;
+    private final ConcurrentMap<T, Integer> cache;
     private final AtomicInteger idGen = new AtomicInteger();
 
     public SimpleCache() {
@@ -37,32 +38,40 @@ public SimpleCache(int cacheSize) {
         this.cache = createCache(cacheSize);
     }
 
-    private ConcurrentMap<T, Result<Integer>> createCache(int maxCacheSize) {
+    private ConcurrentMap<T, Integer> createCache(int maxCacheSize) {
         final Caffeine<Object, Object> cacheBuilder = CaffeineBuilder.newBuilder();
         cacheBuilder.initialCapacity(maxCacheSize);
         cacheBuilder.maximumSize(maxCacheSize);
-        com.github.benmanes.caffeine.cache.Cache<T, Result<Integer>> localCache = cacheBuilder.build();
+        com.github.benmanes.caffeine.cache.Cache<T, Integer> localCache = cacheBuilder.build();
         return localCache.asMap();
     }
 
     @Override
     public Result<Integer> put(T value) {
-        final Result<Integer> find = this.cache.get(value);
-        if (find != null) {
-            return find;
+        final FirstCall mapping = new FirstCall();
+        final Integer id = this.cache.computeIfAbsent(value, mapping);
+        if (mapping.called) {
+            return new Result<>(true, id);
+        } else {
+            return new Result<>(false, id);
         }
-
-        // Use negative values too to reduce data size
-        final int newId = nextId();
-        final Result<Integer> result = new Result<>(false, newId);
-        final Result<Integer> before = this.cache.putIfAbsent(value, result);
-        if (before != null) {
-            return before;
-        }
-        return new Result<>(true, newId);
     }
 
     private int nextId() {
         return this.idGen.incrementAndGet();
     }
+
+    private class FirstCall implements Function<T, Integer> {
+
+        private boolean called;
+
+        public FirstCall() {
+        }
+
+        @Override
+        public Integer apply(T key) {
+            this.called = true;
+            return nextId();
+        }
+    }
 }