Resolve an external domain class by traversing class hierarchy

Author: nakamura-to

src/main/java/org/seasar/doma/internal/util/ClassUtil.java

@@ -23,6 +23,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.function.Function;
 
 import org.seasar.doma.internal.WrapException;
 
@@ -152,4 +153,30 @@ public static Class<?> toBoxedPrimitiveTypeIfPossible(Class<?> clazz) {
         }
         return clazz;
     }
+
+    public static <R> R traverse(Class<?> clazz, Function<Class<?>, R> f) {
+        assertNotNull(clazz);
+        {
+            R result = f.apply(clazz);
+            if (result != null) {
+                return result;
+            }
+        }
+        for (Class<?> c : clazz.getInterfaces()) {
+            R result = traverse(c, f);
+            if (result != null) {
+                return result;
+            }
+        }
+        Class<?> superclass = clazz.getSuperclass();
+        if (superclass == null) {
+            return null;
+        }
+        R result = traverse(superclass, f);
+        if (result != null) {
+            return result;
+        }
+        return null;
+    }
+
 }

src/main/java/org/seasar/doma/jdbc/domain/DomainTypeFactory.java

@@ -151,10 +151,21 @@ public static <BASIC, DOMAIN> DomainType<BASIC, DOMAIN> getExternalDomainType(
         if (classHelper == null) {
             throw new DomaNullPointerException("classHelper");
         }
-        String domainTypeClassName = Constants.EXTERNAL_DOMAIN_METATYPE_ROOT_PACKAGE
-                + "." + Conventions.toFullMetaName(domainClass.getName());
+        Class<?> clazz = ClassUtil.traverse(domainClass, c -> {
+            String domainTypeClassName = Constants.EXTERNAL_DOMAIN_METATYPE_ROOT_PACKAGE
+                    + "." + Conventions.toFullMetaName(c.getName());
+            try {
+                return classHelper.forName(domainTypeClassName);
+            } catch (WrapException e) {
+                return null;
+            } catch (Exception e) {
+                return null;
+            }
+        });
+        if (clazz == null) {
+            return null;
+        }
         try {
-            Class<DOMAIN> clazz = classHelper.forName(domainTypeClassName);
             Method method = ClassUtil.getMethod(clazz, "getSingletonInternal");
             return MethodUtil.invoke(method, null);
         } catch (WrapException e) {

src/test/java/org/seasar/doma/internal/util/ClassUtilTest.java

@@ -17,6 +17,7 @@
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
+import java.util.ArrayList;
 import java.util.List;
 
 import junit.framework.TestCase;
@@ -70,4 +71,39 @@ public void testGetEnclosingNames_nestedClass() {
         assertEquals("Ddd", names.get(1));
     }
 
+    public void testTraverse() throws Exception {
+        List<Class<?>> list = new ArrayList<>();
+        ClassUtil.traverse(Ccc.class, c -> {
+            list.add(c);
+            return null;
+        });
+        assertEquals(8, list.size());
+        assertEquals(Ccc.class, list.get(0));
+        assertEquals(ICcc.class, list.get(1));
+        assertEquals(Bbb.class, list.get(2));
+        assertEquals(IBbb.class, list.get(3));
+        assertEquals(IAaa.class, list.get(4));
+        assertEquals(Aaa.class, list.get(5));
+        assertEquals(IAaa.class, list.get(6));
+        assertEquals(Object.class, list.get(7));
+    }
+
+    private interface IAaa {
+    }
+
+    private interface IBbb extends IAaa {
+    }
+
+    private interface ICcc {
+    }
+
+    private static class Aaa implements IAaa {
+    }
+
+    private static class Bbb extends Aaa implements IBbb {
+    }
+
+    private static class Ccc extends Bbb implements ICcc {
+    }
+
 }