Merge pull request #229 from jhaber/master

Better detection of map type parameters

Author: oliemansm

pom.xml

@@ -50,6 +50,11 @@
             <artifactId>graphql-java</artifactId>
             <version>11.0</version>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml</groupId>
+            <artifactId>classmate</artifactId>
+            <version>1.4.0</version>
+        </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-core</artifactId>

src/main/kotlin/com/coxautodev/graphql/tools/GenericType.kt

@@ -1,5 +1,6 @@
 package com.coxautodev.graphql.tools
 
+import com.fasterxml.classmate.ResolvedType
 import com.google.common.primitives.Primitives
 import org.apache.commons.lang3.reflect.TypeUtils
 import sun.reflect.generics.reflectiveObjects.ParameterizedTypeImpl
@@ -131,6 +132,14 @@ internal open class GenericType(protected val mostSpecificType: JavaType, protec
                     val actualTypeArguments = type.actualTypeArguments.map { replaceTypeVariable(it) }.toTypedArray()
                     ParameterizedTypeImpl.make(type.rawType as Class<*>?, actualTypeArguments, type.ownerType)
                 }
+                is ResolvedType -> {
+                    if (type.typeParameters.isEmpty()) {
+                        type.erasedType
+                    } else {
+                        val actualTypeArguments = type.typeParameters.map { replaceTypeVariable(it) }.toTypedArray()
+                        ParameterizedTypeImpl.make(type.erasedType, actualTypeArguments, null)
+                    }
+                }
                 is TypeVariable<*> -> {
                     if (declaringType is ParameterizedType) {
                         TypeUtils.getRawType(type, declaringType)

src/main/kotlin/com/coxautodev/graphql/tools/PropertyMapResolver.kt

@@ -1,9 +1,9 @@
 package com.coxautodev.graphql.tools
 
+import com.fasterxml.classmate.TypeResolver
 import graphql.language.FieldDefinition
 import graphql.schema.DataFetcher
 import graphql.schema.DataFetchingEnvironment
-import java.lang.reflect.ParameterizedType
 
 /**
  * @author Nick Weedon
@@ -14,12 +14,17 @@ internal class PropertyMapResolver(field: FieldDefinition, search: FieldResolver
 
     var mapGenericValue : JavaType = getMapGenericType(relativeTo)
 
+    /**
+     * Takes a type which implements Map and tries to find the
+     * value type of that map. For some reason, mapClass is losing
+     * its generics somewhere along the way and is always a raw
+     * type
+     */
     fun getMapGenericType(mapClass : JavaType) : JavaType {
-        if(mapClass is ParameterizedType) {
-            return mapClass.actualTypeArguments[1]
-        } else {
-            return Object::class.java
-        }
+        val resolvedType = TypeResolver().resolve(mapClass)
+
+        val typeParameters = resolvedType.typeParametersFor(Map::class.java)
+        return typeParameters.elementAtOrElse(1) { Object::class.java }
     }
 
     override fun createDataFetcher(): DataFetcher<*> {