Artemis: Refactor QueryRequest cache key generation for performance

src/main/java/com/llmproxy/service/cache/CacheService.java

@@ -1,7 +1,5 @@
 package com.llmproxy.service.cache;
 
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.ObjectMapper;
 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.llmproxy.model.QueryRequest;
@@ -13,89 +11,86 @@
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
-import java.util.HashMap;
-import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
 @Service
 @Slf4j
 public class CacheService {
     private final Cache<String, QueryResponse> cache;
-    private final ObjectMapper objectMapper;
     private final boolean enabled;
-    
+
     public CacheService(
             @Value("${cache.enabled:true}") boolean enabled,
             @Value("${cache.ttl.seconds:300}") int ttlSeconds,
             @Value("${cache.max-items:1000}") int maxItems,
-            ObjectMapper objectMapper) {
-        
+            com.fasterxml.jackson.databind.ObjectMapper objectMapper // Kept for bean compatibility, but not used
+    ) {
         this.enabled = enabled;
-        this.objectMapper = objectMapper;
-
+
         this.cache = Caffeine.newBuilder()
                 .maximumSize(maxItems)
                 .expireAfterWrite(ttlSeconds, TimeUnit.SECONDS)
                 .build();
-        
+
         log.info("Cache initialized: enabled={}, ttl={}s, maxItems={}", enabled, ttlSeconds, maxItems);
     }
-    
+
     public QueryResponse get(QueryRequest request) {
         if (!enabled) {
             return null;
         }
-        
+
         String cacheKey = generateCacheKey(request);
         QueryResponse cachedResponse = cache.getIfPresent(cacheKey);
-        
+
         if (cachedResponse != null) {
             log.debug("Cache hit for key: {}", cacheKey);
             return cachedResponse;
         }
-        
+
         log.debug("Cache miss for key: {}", cacheKey);
         return null;
     }
-    
+
     public void set(QueryRequest request, QueryResponse response) {
         if (!enabled) {
             return;
         }
-        
+
         String cacheKey = generateCacheKey(request);
         cache.put(cacheKey, response);
-        
+
         log.debug("Added response to cache with key: {}, model: {}", cacheKey, response.getModel());
     }
-    
+
     private String generateCacheKey(QueryRequest request) {
-        Map<String, String> data = new HashMap<>();
-        data.put("query", request.getQuery());
-        data.put("model", request.getModel() != null ? request.getModel().toString() : "");
-        data.put("task_type", request.getTaskType() != null ? request.getTaskType().toString() : "");
-
+        // Efficiently build the key string
+        String query = request.getQuery() != null ? request.getQuery() : "";
+        String model = request.getModel() != null ? request.getModel().toString() : "";
+        String taskType = request.getTaskType() != null ? request.getTaskType().toString() : "";
+
+        StringBuilder keyBuilder = new StringBuilder();
+        keyBuilder.append("query:").append(query).append(';');
+        keyBuilder.append("model:").append(model).append(';');
+        keyBuilder.append("task_type:").append(taskType);
+
+        String rawKey = keyBuilder.toString();
         try {
-            String jsonData = objectMapper.writeValueAsString(data);
             MessageDigest digest = MessageDigest.getInstance("SHA-256");
-            byte[] hash = digest.digest(jsonData.getBytes(StandardCharsets.UTF_8));
-
-            StringBuilder hexString = new StringBuilder();
-            for (byte b : hash) {
-                String hex = Integer.toHexString(0xff & b);
-                if (hex.length() == 1) {
-                    hexString.append('0');
-                }
-                hexString.append(hex);
+            byte[] hash = digest.digest(rawKey.getBytes(StandardCharsets.UTF_8));
+            // Efficient hex conversion
+            char[] hexArray = "0123456789abcdef".toCharArray();
+            char[] hexChars = new char[hash.length * 2];
+            for (int j = 0; j < hash.length; j++) {
+                int v = hash[j] & 0xFF;
+                hexChars[j * 2] = hexArray[v >>> 4];
+                hexChars[j * 2 + 1] = hexArray[v & 0x0F];
             }
-            return hexString.toString();
-
-        } catch (JsonProcessingException | NoSuchAlgorithmException e) {
+            return new String(hexChars);
+        } catch (NoSuchAlgorithmException e) {
             log.error("Error generating cache key: {}", e.getMessage());
-            return String.format("%s:%s:%s", 
-                request.getQuery(), 
-                request.getModel(), 
-                request.getTaskType());
+            // fallback: direct key (may potentially expose internal details if logged in error)
+            return rawKey;
         }
     }
-}
+}