Moved all validation into the validator.Now it also checks that the

@GraphQLConnection is used correctly on fields

Author: guy120494

src/main/java/graphql/annotations/connection/ConnectionDataFetcher.java

@@ -14,16 +14,12 @@
  */
 package graphql.annotations.connection;
 
-import graphql.annotations.ExtensionDataFetcherWrapper;
 import graphql.relay.Connection;
 import graphql.schema.DataFetcher;
 import graphql.schema.DataFetchingEnvironment;
-import graphql.schema.FieldDataFetcher;
-import graphql.schema.PropertyDataFetcher;
 
 import java.lang.reflect.Constructor;
 import java.util.Arrays;
-import java.util.List;
 import java.util.Optional;
 
 import static graphql.annotations.ReflectionKit.constructNewInstance;
@@ -32,10 +28,8 @@ public class ConnectionDataFetcher<T> implements DataFetcher<Connection<T>> {
     private final Class<? extends ConnectionFetcher<T>> connection;
     private final DataFetcher<PaginatedData<T>> actualDataFetcher;
     private final Constructor<ConnectionFetcher<T>> constructor;
-    private final List<Class<?>> blackListOfDataFetchers = Arrays.asList(PropertyDataFetcher.class, FieldDataFetcher.class);
 
     public ConnectionDataFetcher(Class<? extends ConnectionFetcher<T>> connection, DataFetcher<T> actualDataFetcher) {
-        validateDataFetcher(actualDataFetcher);
         this.connection = connection;
         this.actualDataFetcher = (DataFetcher<PaginatedData<T>>) actualDataFetcher;
         Optional<Constructor<ConnectionFetcher<T>>> constructor =
@@ -50,17 +44,6 @@ public ConnectionDataFetcher(Class<? extends ConnectionFetcher<T>> connection, D
         }
     }
 
-    private void validateDataFetcher(DataFetcher<?> dataFetcher) {
-        if( dataFetcher instanceof ExtensionDataFetcherWrapper) {
-            dataFetcher = ((ExtensionDataFetcherWrapper) dataFetcher).getUnwrappedDataFetcher();
-        }
-        final DataFetcher<?> finalDataFetcher = dataFetcher;
-        if(blackListOfDataFetchers.stream().anyMatch(aClass -> aClass.isInstance(finalDataFetcher))) {
-            throw new GraphQLConnectionException("Please don't use @GraphQLConnection on a field without @GraphQLDataFetcher, because " +
-                    "neither PropertyDataFetcher nor FieldDataFetcher know how to handle connection");
-        }
-    }
-
     @Override
     public Connection<T> get(DataFetchingEnvironment environment) {
         ConnectionFetcher<T> conn = constructNewInstance(constructor, actualDataFetcher);

src/main/java/graphql/annotations/connection/ConnectionTypeValidator.java

@@ -1,33 +1,40 @@
 /**
  * Copyright 2016 Yurii Rashkovskii
- *
+ * <p>
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  */
 package graphql.annotations.connection;
 
+import graphql.annotations.GraphQLDataFetcher;
+
 import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 
 public class ConnectionTypeValidator {
 
     public void validate(AccessibleObject field) {
-        if(field instanceof Field) {
-            if(!PaginatedData.class.isAssignableFrom(((Field)field).getType())) {
+        if (field instanceof Field) {
+            if (field.isAnnotationPresent(GraphQLConnection.class) && !field.isAnnotationPresent(GraphQLDataFetcher.class)) {
+                throw new GraphQLConnectionException("Please don't use @GraphQLConnection on" + ((Field) field).getName() +
+                        " without @GraphQLDataFetcher, because " +
+                        "neither PropertyDataFetcher nor FieldDataFetcher know how to handle connection");
+            }
+
+            if (!PaginatedData.class.isAssignableFrom(((Field) field).getType())) {
                 throw new GraphQLConnectionException(((Field) field).getName() + " type must be PaginatedData");
             }
-        }
-        else {
-            if(!PaginatedData.class.isAssignableFrom(((Method)field).getReturnType())){
+        } else {
+            if (!PaginatedData.class.isAssignableFrom(((Method) field).getReturnType())) {
                 throw new GraphQLConnectionException(((Method) field).getName() + " return type must be PaginatedData");
             }
         }