Fix GenericType resolution in parameterized classes

Port the code from geantryref.TypeToken#extractType for classes passed into GenericType. Fixes jdbi#2305
hgschmie · Mar 24, 2023 · a53d152 · a53d152
1 parent 118c1cc
commit a53d152
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diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
@@ -1,5 +1,6 @@
 # Unreleased
 
+  - fix `GenericType` creation in parameterized classes (#2305)
   - add `SqlStatements#setAttachAllStatementsForCleanup`. Setting this configuration flag will attach all created statements to their handles for resource cleanup. Default is `false`. (#2293, thanks @jodastephen)
   - add `SqlStatements#setAttachCallbackStatementsForCleanup`. Setting this configuration flag will attach all created statements within one of the `Jdbi` callback methods to the handle. This allows code that uses the `Jdbi` callback methods to delegate resource management fully to Jdbi. This flag is set by default. (#2293, thanks @jodastephen)
   - fix problem when using the jdbi bom in spring projects (#2295, thanks @jedvardsson)

diff --git a/core/src/main/java/org/jdbi/v3/core/generic/GenericTypes.java b/core/src/main/java/org/jdbi/v3/core/generic/GenericTypes.java
@@ -13,6 +13,8 @@
  */
 package org.jdbi.v3.core.generic;
 
+import java.lang.reflect.AnnotatedParameterizedType;
+import java.lang.reflect.AnnotatedType;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
@@ -100,7 +102,20 @@ public static Optional<Type> findGenericParameter(Type type, Class<?> parameteri
      * @return the parameter on the supertype, if it is concretely defined.
      * @throws ArrayIndexOutOfBoundsException if n &gt; the number of type variables the type has
      */
+    @SuppressWarnings("PMD.AvoidDeeplyNestedIfStmts")
     public static Optional<Type> findGenericParameter(Type type, Class<?> parameterizedSupertype, int n) {
+        if (type instanceof Class) {
+            // this is the same code as TypeToken#extractType
+            AnnotatedType t = ((Class) type).getAnnotatedSuperclass();
+            if (t instanceof AnnotatedParameterizedType) {
+                AnnotatedParameterizedType pt = (AnnotatedParameterizedType) t;
+                if (((ParameterizedType) pt.getType()).getRawType() == parameterizedSupertype) {
+                    return Optional.ofNullable(pt.getAnnotatedActualTypeArguments()[n]).map(AnnotatedType::getType);
+                }
+            }
+        }
+
+        // fall back to the type reflector
         return Optional.ofNullable(GenericTypeReflector.getTypeParameter(type, parameterizedSupertype.getTypeParameters()[n]));
     }
 

diff --git a/core/src/test/java/org/jdbi/v3/core/generic/GenericTypesTest.java b/core/src/test/java/org/jdbi/v3/core/generic/GenericTypesTest.java
@@ -14,6 +14,7 @@
 package org.jdbi.v3.core.generic;
 
 import java.lang.reflect.Type;
+import java.util.List;
 import java.util.Optional;
 
 import org.junit.jupiter.api.Test;
@@ -77,6 +78,17 @@ public void findMultipleGenericParameters() throws NoSuchMethodException {
             .contains(Void.class);
     }
 
+    @Test
+    void testGenericTypeWorksInParameterizedClasses() {
+        class Foo<T> {
+            Type getType() {
+                return new GenericType<List<String>>() {}.getType();
+            }
+        }
+
+        assertThat(new Foo<>().getType()).isNotNull();
+    }
+
     @Test
     public void resolveType() throws NoSuchMethodException {
         abstract class A<T> {