Merge pull request #175 from yarinvak/fix-method-data-fetcher

Fix method data fetcher problems - now the hirearchy is clearer:
1. if annotated with ``@GraphQLInvokeDetached`` - execute the method. else:
2. if the declaring class is not an instance of the source object, try to construct a declaring class object from the source and return its value. else:
3. if source object is null, return null. else:
4. if source is not null, search for method in source with the field name / get"FieldName" method/ is"FieldName" method / field with the same name which has value

Author: yarinvak

gradle.properties

@@ -7,4 +7,4 @@ org.gradle.jvmargs=-Dfile.encoding=UTF-8
 
 bintray.user=DUMMY_USER
 bintray.key=DUMMY_KEY
-version = 5.2
+version = 5.3

secret2.gpg

@@ -5,7 +5,7 @@
  * 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
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
@@ -27,6 +27,7 @@
 import java.util.Map;
 
 import static graphql.annotations.processor.util.NamingKit.toGraphqlName;
+import static graphql.annotations.processor.util.PrefixesUtil.addPrefixToPropertyName;
 import static graphql.annotations.processor.util.ReflectionKit.constructNewInstance;
 import static graphql.annotations.processor.util.ReflectionKit.newInstance;
 
@@ -58,7 +59,7 @@ public T get(DataFetchingEnvironment environment) {
             }
 
             if (obj == null && environment.getSource() != null) {
-                Object value = getFieldValue(environment.getSource(), method.getName());
+                Object value = getGraphQLFieldValue(environment.getSource(), environment.getField().getName());
                 return (T) value;
             }
 
@@ -135,9 +136,59 @@ private Object buildArg(Type p, GraphQLType graphQLType, Object arg) {
         }
     }
 
-    private Object getFieldValue(Object source, String fieldName) throws IllegalAccessException, NoSuchFieldException {
-        Field field = source.getClass().getDeclaredField(fieldName);
-        field.setAccessible(true);
-        return field.get(source);
+    private Object getGraphQLFieldValue(Object source, String fieldName) throws IllegalAccessException, NoSuchFieldException, InvocationTargetException {
+        Object methodValue = getValueFromMethod(source, fieldName);
+        if (methodValue != null) return methodValue;
+
+        Field field = getField(source.getClass(), fieldName);
+        if (getValueFromField(field)) return field.get(source);
+
+        throw new NoSuchFieldException("No GraphQL field found");
+    }
+
+    private boolean getValueFromField(Field field) throws IllegalAccessException {
+        if (field != null) {
+            field.setAccessible(true);
+            return true;
+        }
+        return false;
     }
+
+    private Object getValueFromMethod(Object source, String fieldName) throws IllegalAccessException, InvocationTargetException {
+        String[] orderedPrefixes = new String[]{"", "get", "is"};
+        for (String orderedPrefix : orderedPrefixes) {
+            Method method = getMethod(source.getClass(), fieldName, orderedPrefix);
+            if (method != null) {
+                return method.invoke(source);
+            }
+        }
+        return null;
+    }
+
+    private Method getMethod(Class<?> clazz, String name, String prefix) {
+        String prefixedName = addPrefixToPropertyName(prefix, name);
+        Method method = null;
+        while (clazz != null && method == null) {
+            try {
+                method = clazz.getDeclaredMethod(prefixedName);
+            } catch (Exception ignored) {
+            }
+            clazz = clazz.getSuperclass();
+        }
+
+        return method;
+    }
+
+    private Field getField(Class<?> clazz, String name) {
+        Field field = null;
+        while (clazz != null && field == null) {
+            try {
+                field = clazz.getDeclaredField(name);
+            } catch (Exception ignored) {
+            }
+            clazz = clazz.getSuperclass();
+        }
+        return field;
+    }
+
 }

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

@@ -32,13 +32,13 @@ public MethodNameBuilder(Method method) {
     @Override
     public String build() {
         if (method.isAnnotationPresent(GraphQLPrettify.class) && !method.isAnnotationPresent(GraphQLName.class)) {
-            return toGraphqlName(pretifyName(method.getName()));
+            return toGraphqlName(prettifyName(method.getName()));
         }
         GraphQLName name = method.getAnnotation(GraphQLName.class);
         return toGraphqlName(name == null ? method.getName() : name.value());
     }
 
-    private String pretifyName(String originalName) {
+    private String prettifyName(String originalName) {
         String name = originalName.replaceFirst("^(is|get|set)(.+)", "$2");
         return Character.toLowerCase(name.charAt(0)) + name.substring(1);
     }

src/main/java/graphql/annotations/processor/retrievers/fieldBuilders/method/MethodNameBuilder.java

@@ -0,0 +1,21 @@
+/**
+ * Copyright 2016 Yurii Rashkovskii
+ *
+ * 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
+ *
+ * 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.processor.util;
+
+public class PrefixesUtil {
+    public static String addPrefixToPropertyName(String prefix, String propertyName) {
+        return prefix + propertyName.substring(0, 1).toUpperCase() + propertyName.substring(1);
+    }
+}