Add suggestions from the code review

Author: DimuthuMadushan

ballerina/annotation_processor.bal

@@ -127,7 +127,7 @@ isolated function getInterceptorConfig(readonly & Interceptor interceptor) retur
     return classType.@InterceptorConfig;
 }
 
-isolated function getCacheConfig(GraphqlServiceConfig? serviceConfig) returns ServerCacheConfig? {
+isolated function getCacheConfig(GraphqlServiceConfig? serviceConfig) returns readonly & ServerCacheConfig? {
     if serviceConfig is GraphqlServiceConfig {
         if serviceConfig.cacheConfig is ServerCacheConfig {
             return serviceConfig.cacheConfig;
@@ -136,7 +136,7 @@ isolated function getCacheConfig(GraphqlServiceConfig? serviceConfig) returns Se
     return;
 }
 
-isolated function getFieldCacheConfigFromServiceConfig(GraphqlServiceConfig? serviceConfig) returns ServerCacheConfig? {
+isolated function getFieldCacheConfigFromServiceConfig(GraphqlServiceConfig? serviceConfig) returns readonly & ServerCacheConfig? {
     if serviceConfig is GraphqlServiceConfig {
         return serviceConfig.fieldCacheConfig;
     }

ballerina/engine.bal

@@ -31,7 +31,8 @@ isolated class Engine {
 
     isolated function init(string schemaString, int? maxQueryDepth, Service s,
                            readonly & (readonly & Interceptor)[] interceptors, boolean introspection,
-                           boolean validation, ServerCacheConfig? cacheConfig = (), ServerCacheConfig? fieldCacheConfig = ())
+                           boolean validation, ServerCacheConfig? cacheConfig = (),
+                           ServerCacheConfig? fieldCacheConfig = ())
     returns Error? {
         if maxQueryDepth is int && maxQueryDepth < 1 {
             return error Error("Max query depth value must be a positive integer");
@@ -41,7 +42,7 @@ isolated class Engine {
         self.interceptors = interceptors;
         self.introspection = introspection;
         self.validation = validation;
-        self.cacheConfig = cacheConfig.cloneReadOnly();
+        self.cacheConfig = cacheConfig;
         self.cache = initCacheTable(cacheConfig, fieldCacheConfig);
         self.addService(s);
     }
@@ -284,7 +285,8 @@ isolated class Engine {
 
         (readonly & Interceptor)? interceptor = context.getNextInterceptor('field);
         __Type fieldType = 'field.getFieldType();
-        ResponseGenerator responseGenerator = new (self, context, fieldType, 'field.getPath().clone(), 'field.getCacheConfig().clone(), 'field.getParentArgHashes().clone());
+        ResponseGenerator responseGenerator = new (self, context, fieldType, 'field.getPath().clone(),
+                                                   'field.getCacheConfig(), 'field.getParentArgHashes());
         do {
             if interceptor is readonly & Interceptor {
                 any|error result = self.executeInterceptor(interceptor, 'field, context);

ballerina/field.bal

@@ -27,12 +27,14 @@ public class Field {
     private string[] resourcePath;
     private readonly & Interceptor[] fieldInterceptors;
     private final ServerCacheConfig? cacheConfig;
-    private final string[] parentArgHashes;
+    private final readonly & string[] parentArgHashes;
+    private final boolean cacheEnabled;
+    private final decimal cacheMaxAge;
 
     isolated function init(parser:FieldNode internalNode, __Type fieldType, service object {}? serviceObject = (),
                            (string|int)[] path = [], parser:RootOperationType operationType = parser:OPERATION_QUERY,
                            string[] resourcePath = [], any|error fieldValue = (), ServerCacheConfig? cacheConfig = (),
-                           string[] parentArgHashes = []) {
+                           readonly & string[] parentArgHashes = []) {
         self.internalNode = internalNode;
         self.serviceObject = serviceObject;
         self.fieldType = fieldType;
@@ -45,8 +47,16 @@ public class Field {
             getFieldInterceptors(serviceObject, operationType, internalNode.getName(), self.resourcePath) : [];
         ServerCacheConfig? fieldCache = serviceObject is service object {} ?
             getFieldCacheConfig(serviceObject, operationType, internalNode.getName(), self.resourcePath) : ();
-        self.cacheConfig = fieldCache is ServerCacheConfig ? fieldCache : cacheConfig;
+        ServerCacheConfig? updatedCacheConfig = fieldCache is ServerCacheConfig ? fieldCache : cacheConfig;
+        self.cacheConfig = updatedCacheConfig;
         self.parentArgHashes = parentArgHashes;
+        if updatedCacheConfig is ServerCacheConfig {
+            self.cacheEnabled = updatedCacheConfig.enabled;
+            self.cacheMaxAge = updatedCacheConfig.maxAge;
+        } else {
+            self.cacheEnabled = false;
+            self.cacheMaxAge = 0d;
+        }
     }
 
     # Returns the name of the field.
@@ -136,8 +146,8 @@ public class Field {
                 foreach __Field 'field in typeFields {
                     if 'field.name == selection.getName() {
                         result.push(new Field(selection, 'field.'type, (),[...currentPath, ...unwrappedPath, 'field.name],
-                            self.operationType.clone(), self.resourcePath.clone(), cacheConfig = self.cacheConfig.clone(),
-                            parentArgHashes = self.parentArgHashes.clone()));
+                            self.operationType.clone(), self.resourcePath.clone(), cacheConfig = self.cacheConfig,
+                            parentArgHashes = self.parentArgHashes));
                         break;
                     }
                 }
@@ -170,8 +180,7 @@ public class Field {
     }
 
     isolated function isCacheEnabled() returns boolean {
-        ServerCacheConfig? cacheConfig = self.getCacheConfig();
-        return cacheConfig is ServerCacheConfig && cacheConfig.enabled;
+        return self.cacheEnabled;
     }
 
     isolated function getCacheConfig() returns ServerCacheConfig? {
@@ -183,14 +192,10 @@ public class Field {
     }
 
     isolated function getCacheMaxAge() returns decimal {
-        ServerCacheConfig? cacheConfig = self.getCacheConfig();
-        if cacheConfig is ServerCacheConfig {
-            return cacheConfig.maxAge;
-        }
-        return 0d;
+        return self.cacheMaxAge;
     }
 
-    isolated function getParentArgHashes() returns string[] {
+    isolated function getParentArgHashes() returns readonly & string[] {
         return self.parentArgHashes;
     }
 

ballerina/listener.bal

@@ -77,7 +77,8 @@ public class Listener {
         if self.graphiql.enabled {
             check validateGraphiqlPath(self.graphiql.path);
             string gqlServiceBasePath = name is () ? "" : getBasePath(name);
-            engine = check new (schemaString, maxQueryDepth, s, interceptors, introspection, validation, operationCacheConfig, fieldCacheConfig);
+            engine = check new (schemaString, maxQueryDepth, s, interceptors, introspection, validation,
+                                operationCacheConfig, fieldCacheConfig);
             __Schema & readonly schema = engine.getSchema();
             __Type? subscriptionType = schema.subscriptionType;
             string graphqlUrl = string `${self.httpEndpoint}/${gqlServiceBasePath}`;
@@ -91,7 +92,8 @@ public class Listener {
                 return error Error("Error occurred while attaching the GraphiQL endpoint", result);
             }
         } else {
-            engine = check new (schemaString, maxQueryDepth, s, interceptors, introspection, validation, operationCacheConfig, fieldCacheConfig);
+            engine = check new (schemaString, maxQueryDepth, s, interceptors, introspection, validation,
+                                operationCacheConfig, fieldCacheConfig);
         }
 
         HttpService httpService = getHttpService(engine, serviceConfig);

ballerina/response_generator.bal

@@ -23,12 +23,13 @@ class ResponseGenerator {
     private final Context context;
     private (string|int)[] path;
     private final __Type fieldType;
-    private final ServerCacheConfig? cacheConfig;
-    private final string[] parentArgHashes;
+    private final readonly & ServerCacheConfig? cacheConfig;
+    private final readonly & string[] parentArgHashes;
 
     private final string functionNameGetFragmentFromService = "";
 
-    isolated function init(Engine engine, Context context, __Type fieldType, (string|int)[] path = [], ServerCacheConfig? cacheConfig = (), string[] parentArgHashes = []) {
+    isolated function init(Engine engine, Context context, __Type fieldType, (string|int)[] path = [],
+                           ServerCacheConfig? cacheConfig = (), readonly & string[] parentArgHashes = []) {
         self.engine = engine;
         self.context = context;
         self.path = path;

ballerina/types.bal

@@ -70,7 +70,7 @@ public type Graphiql record {|
 # + enabled - State of the caching
 # + maxAge - TTL of the cache in seconds
 # + maxSize - Maximum number of cache entries
-public type ServerCacheConfig record {|
+public type ServerCacheConfig  readonly & record{|
     boolean enabled = true;
     decimal maxAge = 60;
     int maxSize = 120;

docs/spec/spec.md

@@ -104,14 +104,14 @@ The conforming implementation of the specification is released and included in t
         * 7.1.6 [Service Interceptors](#716-service-interceptors)
         * 7.1.7 [Introspection Configurations](#717-introspection-configurations)
         * 7.1.8 [Constraint Configurations](#718-constraint-configurations)
-        * 7.1.9 [Operation Cache Configurations](#719-operation-cache-configurations)
+        * 7.1.9 [Operation-level Cache Configurations](#719-operation-level-cache-configurations)
             * 7.1.9.1 [The `enabled` Field](#7191-the-enabled-field)
             * 7.1.9.2 [The `maxAge` Field](#7192-the-maxage-field)
             * 7.1.9.3 [The `maxSize` Field](#7193-the-maxsize-field)
     * 7.2 [Resource Configuration](#72-resource-configuration)
         * 7.2.1 [Field Interceptors](#721-field-interceptors)
         * 7.2.2 [Prefetch Method Name Configuration](#722-prefetch-method-name-configuration)
-        * 7.2.3 [Field Cache Configurations](#723-field-cache-configuration)
+        * 7.2.3 [Field-level Cache Configurations](#723-field-level-cache-configuration)
     * 7.3 [Interceptor Configuration](#73-interceptor-configuration)
         * 7.3.1 [Scope Configuration](#731-scope-configuration)
     * 7.4 [ID Annotation](#74-id-annotation)
@@ -202,8 +202,8 @@ The conforming implementation of the specification is released and included in t
             * 10.6.3.3 [Define the Corresponding `prefetch` Method](#10633-define-the-corresponding-prefetch-method)
     * 10.7 [Caching](#107-caching)
         * 10.7.1 [Server-side Caching](#1071-server-side-caching)
-            * 10.7.1.1 [Operation Caching](#10711-operation-caching)
-            * 10.7.1.2 [Field Caching](#10712-field-caching)
+            * 10.7.1.1 [Operation-level Caching](#10711-operation-level-caching)
+            * 10.7.1.2 [Field-level Caching](#10712-field-level-caching)
             * 10.7.1.3 [Cache Eviction](#10713-cache-eviction)
                 * 10.7.1.3.1 [The `invalidate` Method](#107131-the-invalidate-method)
                 * 10.7.1.3.2 [The `invalidateAll` Method](#107132-the-invalidateall-method)
@@ -1774,43 +1774,46 @@ service on new graphql:Listener(9090) {
 }
 ```
 
-#### 7.1.9 Operation Cache Configurations
+#### 7.1.9 Operation-level Cache Configurations
 
-The `cacheConfig` field is used to provide the GraphQL operation cache configuration to enable the caching for `query` operations.
+The `cacheConfig` field is used to provide the GraphQL operation-level cache configuration to enable the caching for `query` operations.
 
-###### Example: Operation Cache Configurations
+###### Example: Enable Operation-level Cache with Default Values
 
 ```ballerina
 @graphql:ServiceConfig {
-    cacheConfig: {
-        enabled: true,
-        maxAge: 60,
-        maxSize: 120
-    }
+    cacheConfig: {}
 }
 service on new graphql:Listener(9090) {
     // ...
 }
 ```
 
-###### Example: Enable Operation Cache with Default Values
+###### Example: Operation-level Cache Configurations
 
 ```ballerina
 @graphql:ServiceConfig {
-    cacheConfig: {}
+    cacheConfig: {
+        enabled: false
+        maxAge: 100,
+        maxSize: 150
+    }
 }
 service on new graphql:Listener(9090) {
     // ...
 }
 ```
 
 ##### 7.1.9.1 The `enabled` Field
+
 The optinal field `enabled` accepts a `boolean` that denotes whether the server-side operation cache is enabled or not. By default, it has been set to `true`.
 
 ##### 7.1.9.2 The `maxAge` Field
-The optional field `maxAge` accepts a valid `decimal` value which considers as the TTL(Time To Live) in seconds. The default maxAge is `60` seconds.
+
+The optional field `maxAge` accepts a valid `decimal` value which is considerd as the TTL(Time To Live) in seconds. The default maxAge is `60` seconds.
 
 ##### 7.1.9.3 The `maxSize` Field
+
 The optional field `maxSize` accepts an int that denotes the maximum number of cache entries in the cache table. By default, it has been set to `120`.
 
 ### 7.2 Resource Configuration
@@ -1873,20 +1876,20 @@ service on new graphql:Listener(9090) {
 }
 ```
 
-#### 7.2.3 Field Cache Configuration
+#### 7.2.3 Field-level Cache Configuration
 
-The `cacheConfig` field is used to provide the field cache configs. The fields are as same as the operation cache configs. The field configurations override the operation configurations.
+The `cacheConfig` field is used to provide the field-level cache configs. The fields are as same as the operation cache configs. The field configurations override the operation configurations.
 
-###### Example: Field Cache Configs
+###### Example: Field-level Cache Configs
 
 ```ballerina
 service on new graphql:Listener(9090) {
 
     @graphql:ResourceConfig {
         cacheConfig: {
             enabled: true,
-            maxAge: 60,
-            maxSize: 120
+            maxAge: 90,
+            maxSize: 80
         }
     }
     resource function get name(int id) returns string {
@@ -3595,7 +3598,7 @@ distinct service class Author {
 }
 ```
 
-###### Example: Overriding the Defalut `prefetch` Method Name
+###### Example: Overriding the Default `prefetch` Method Name
 
 ```ballerina
 distinct service class Author {
@@ -3612,7 +3615,7 @@ distinct service class Author {
 }
 ```
 
-Bringing everything together, the subsequent examples demonstrates how to engage a DataLoader with a GraphQL service.
+Bringing everything together, the subsequent examples demonstrate how to engage a DataLoader with a GraphQL service.
 
 ###### Example: Utilizing a DataLoader in a GraphQL Service
 
@@ -3753,15 +3756,15 @@ This section describes the caching mechanisms in the Ballerina GraphQL module.
 
 #### 10.7.1 Server-side Caching
 
-The Ballerina GraphQL module offers built-in server-side caching for GraphQL `query` operations. The caching operates as in-memory caching, implemented using the Ballerina cache module. The GraphQL module generates cache keys based on the arguments and the path. In server-side caching, the `errors` and `null` values are skipped when caching. There are two different ways called `operation caching` and `field caching` to enable server-side caching.
+The Ballerina GraphQL module offers built-in server-side caching for GraphQL `query` operations. The caching operates as in-memory caching, implemented using the Ballerina cache module. The GraphQL module generates cache keys based on the arguments and the path. In server-side caching, the `errors` and `null` values are skipped when caching. There are two different ways called `operation-level caching` and `field-level caching` to enable server-side caching.
 
-##### 10.7.1.1 Operation Caching
+##### 10.7.1.1 Operation-level Caching
 
-Operation caching can be used to cache the entire operation, and this can be enabled by providing the [operation cache configurations](#719-operation-cache-configurations). Once enabled, the GraphQL server initiates caching for all subfields of `query` operations. The fields requested through query operations will be cached based on the specified cache configurations
+Operation-level caching can be used to cache the entire operation, and this can be enabled by providing the [operation cache configurations](#719-operation-level-cache-configurations). Once enabled, the GraphQL server initiates caching for all subfields of `query` operations. The fields requested through query operations will be cached based on the specified cache configurations
 
-##### 10.7.1.2 Field Caching
+##### 10.7.1.2 Field-level Caching
 
-The GraphQL field caching can be enabled only for a specific field. This can be done by providing the [field cache configurations](#723-field-cache-configuration). Once the field caching is enabled for a field, it will be applied to the sub-fields of that field.
+The GraphQL field-level caching can be enabled only for a specific field. This can be done by providing the [field cache configurations](#723-field-level-cache-configuration). Once the field-level caching is enabled for a field, it will be applied to the sub-fields of that field.
 
 #### 10.7.1.3 Cache Eviction
 
@@ -3783,7 +3786,7 @@ The `invalidateAll` method can be used to clear the entire cache table. This met
 public isolated function invalidateAll() returns error? {}
 ```
 
-###### Example: Operation Cache Enabling and Eviction
+###### Example: Operation-level Cache Enabling and Eviction
 
 ```ballerina
 import ballerina/graphql;
@@ -3816,7 +3819,7 @@ service /graphql on new graphql:Listener(9090) {
 
 In this example, caching is enabled at the operation level. Therefore, the field `name` and `type` will be cached. When updating the name with a mutation, the cached values become invalid. Hence, the `invalidate` function can be used to evict the existing cache values.
 
-###### Example: Field Cache Enabling and Eviction
+###### Example: Field-level Cache Enabling and Eviction
 
 ```ballerina
 import ballerina/graphql;
@@ -3883,4 +3886,4 @@ public isolated distinct service class Person {
 }
 ```
 
-In this example, GraphQL field caching is enabled for the `age` field via the resource configurations. When the age is changed using the `updateAge` operation, the `invalidate` method is used to remove the existing cache entries related to the age field.
+In this example, GraphQL field-level caching is enabled for the `age` field via the resource configurations. When the age is changed using the `updateAge` operation, the `invalidate` method is used to remove the existing cache entries related to the age field.