Fixed a bug where MethodDataFetcher caused NullPointerException

Author: osher-sade

src/main/java/graphql/annotations/dataFetchers/MethodDataFetcher.java

@@ -14,20 +14,19 @@
  */
 package graphql.annotations.dataFetchers;
 
-import graphql.annotations.processor.ProcessingElementsContainer;
 import graphql.annotations.annotationTypes.GraphQLInvokeDetached;
 import graphql.annotations.annotationTypes.GraphQLName;
+import graphql.annotations.processor.ProcessingElementsContainer;
 import graphql.annotations.processor.typeFunctions.TypeFunction;
 import graphql.schema.*;
-import graphql.schema.GraphQLType;
 
 import java.lang.reflect.*;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
-import static graphql.annotations.processor.util.ReflectionKit.constructNewInstance;
 import static graphql.annotations.processor.util.NamingKit.toGraphqlName;
+import static graphql.annotations.processor.util.ReflectionKit.constructNewInstance;
 import static graphql.annotations.processor.util.ReflectionKit.newInstance;
 
 public class MethodDataFetcher<T> implements DataFetcher<T> {
@@ -59,7 +58,13 @@ public T get(DataFetchingEnvironment environment) {
                     return null;
                 }
             }
-            return (T)method.invoke(obj, invocationArgs(environment, container));
+
+            if (obj == null && environment.getSource() != null) {
+                Object value = getFieldValue(environment.getSource(), method.getName());
+                if (value != null) return (T) value;
+            }
+
+            return (T) method.invoke(obj, invocationArgs(environment, container));
         } catch (IllegalAccessException | InvocationTargetException e) {
             throw new RuntimeException(e);
         }
@@ -131,4 +136,14 @@ private Object buildArg(Type p, GraphQLType graphQLType, Object arg) {
             return arg;
         }
     }
+
+    private Object getFieldValue(Object source, String fieldName) throws IllegalAccessException {
+        try {
+            Field field = source.getClass().getDeclaredField(fieldName);
+            field.setAccessible(true);
+            return field.get(source);
+        } catch (NoSuchFieldException e) {
+            return null;
+        }
+    }
 }

src/main/java/graphql/annotations/processor/util/ReflectionKit.java

@@ -69,6 +69,4 @@ public static <T> T newInstance(Class<T> clazz, Object parameter) {
         }
         return null;
     }
-
-
 }

src/test/java/graphql/annotations/MethodDataFetcherTest.java

@@ -14,15 +14,27 @@
  */
 package graphql.annotations;
 
+import graphql.ExecutionResult;
+import graphql.GraphQL;
+import graphql.annotations.annotationTypes.GraphQLDataFetcher;
+import graphql.annotations.annotationTypes.GraphQLField;
+import graphql.annotations.annotationTypes.GraphQLInvokeDetached;
+import graphql.annotations.annotationTypes.GraphQLType;
 import graphql.annotations.dataFetchers.MethodDataFetcher;
 import graphql.annotations.processor.GraphQLAnnotations;
-import graphql.schema.DataFetchingEnvironmentImpl;
+import graphql.schema.*;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Map;
 
+import static graphql.schema.GraphQLSchema.newSchema;
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+
+@SuppressWarnings("unchecked")
 public class MethodDataFetcherTest {
 
     @BeforeMethod
@@ -41,10 +53,84 @@ public String method() throws TestException {
     @Test(expectedExceptions = RuntimeException.class)
     public void exceptionRethrowing() {
         try {
-            MethodDataFetcher methodDataFetcher = new MethodDataFetcher(getClass().getMethod("method"),null,null);
-            methodDataFetcher.get(new DataFetchingEnvironmentImpl(this, new HashMap<String,Object>(), null, null, null, new ArrayList<>(), null, null, null, null, null, null, null));
+            MethodDataFetcher methodDataFetcher = new MethodDataFetcher(getClass().getMethod("method"), null, null);
+            methodDataFetcher.get(new DataFetchingEnvironmentImpl(this, new HashMap<>(), null, null, null, new ArrayList<>(), null, null, null, null, null, null, null));
         } catch (NoSuchMethodException e) {
             e.printStackTrace();
         }
     }
+
+
+    @GraphQLType
+    public static class ApiType {
+        @GraphQLField
+        public int a() {
+            return 1;
+        }
+
+        @GraphQLField
+        @GraphQLInvokeDetached
+        public int b() {
+            return 2;
+        }
+    }
+
+    public static class InternalType {
+        public int a = 123;
+        public int b;
+    }
+
+    @GraphQLType
+    public static class Query {
+        @GraphQLField
+        @GraphQLDataFetcher(MyFetcher.class)
+        public ApiType field;
+
+        @GraphQLField
+        @GraphQLDataFetcher(MyApiFetcher.class)
+        public ApiType apiField;
+    }
+
+    public static class MyFetcher implements DataFetcher<InternalType> {
+        public InternalType get(DataFetchingEnvironment environment) {
+            return new InternalType();
+        }
+    }
+
+    public static class MyApiFetcher implements DataFetcher<ApiType> {
+        public ApiType get(DataFetchingEnvironment environment) {
+            return new ApiType();
+        }
+    }
+
+    @Test
+    public void queryingOneFieldNotAnnotatedWithGraphQLInvokeDetached_valueIsDeterminedByEntity() {
+        GraphQLObjectType object = GraphQLAnnotations.object(Query.class);
+        GraphQLSchema schema = newSchema().query(object).build();
+
+        ExecutionResult result = GraphQL.newGraphQL(schema).build().execute("query { field { a } }");
+        assertTrue(result.getErrors().isEmpty());
+        assertEquals(((Map<String, Map<String, Integer>>) result.getData()).get("field").get("a").toString(), "123");
+    }
+
+    @Test
+    public void queryingOneFieldAnnotatedWithGraphQLInvokeDetached_valueIsDeterminedByApiEntity() {
+        GraphQLObjectType object = GraphQLAnnotations.object(Query.class);
+        GraphQLSchema schema = newSchema().query(object).build();
+
+        ExecutionResult result = GraphQL.newGraphQL(schema).build().execute("query { field { b } }");
+        assertTrue(result.getErrors().isEmpty());
+        assertEquals(((Map<String, Map<String, Integer>>) result.getData()).get("field").get("b").toString(), "2");
+    }
+
+    @Test
+    public void queryingFieldsFromApiEntityFetcher_valueIsDeterminedByApiEntity() {
+        GraphQLObjectType object = GraphQLAnnotations.object(Query.class);
+        GraphQLSchema schema = newSchema().query(object).build();
+
+        ExecutionResult result = GraphQL.newGraphQL(schema).build().execute("query { apiField { a b } }");
+        assertTrue(result.getErrors().isEmpty());
+        assertEquals(((Map<String, Map<String, Integer>>) result.getData()).get("apiField").get("a").toString(), "1");
+        assertEquals(((Map<String, Map<String, Integer>>) result.getData()).get("apiField").get("b").toString(), "2");
+    }
 }