polish

org.springframework.context/src/main/java/org/springframework/mapping/support/SpelMapper.java

@@ -24,6 +24,7 @@ import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.springframework.core.GenericTypeResolver;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.convert.converter.ConverterRegistry;
@@ -115,6 +116,16 @@ public class SpelMapper implements Mapper<Object, Object> {
 		return mapping;
 	}
 
+	/**
+	 * Adds a Mapper to apply to complex nested property mappings of a specific sourceType/targetType pair.
+	 * The source and target types are determined by introspecting the parameterized types on the implementation's Mapper generic interface.
+	 * @param nestedMapper the nested mapper
+	 */
+	public void addNestedMapper(Mapper<?, ?> nestedMapper) {
+		Class[] typeInfo = getRequiredTypeInfo(nestedMapper);
+		addNestedMapper(typeInfo[0], typeInfo[1], nestedMapper);
+	}
+
 	/**
 	 * Adds a Mapper to apply to complex nested property mappings of a specific sourceType/targetType pair.
 	 * @param sourceType the source nested property type
@@ -159,6 +170,10 @@ public class SpelMapper implements Mapper<Object, Object> {
 
 	// internal helpers
 
+	private Class[] getRequiredTypeInfo(Mapper mapper) {
+		return GenericTypeResolver.resolveTypeArguments(mapper.getClass(), Mapper.class);
+	}
+
 	private EvaluationContext getEvaluationContext(Object object) {
 		return mappableTypeFactory.getMappableType(object).getEvaluationContext(object, this.conversionService);
 	}

org.springframework.context/src/test/java/org/springframework/mapping/support/SpelMapperTests.java

@@ -12,6 +12,7 @@ import java.util.Map;
 
 import org.junit.Test;
 import org.springframework.core.convert.converter.Converter;
+import org.springframework.mapping.Mapper;
 import org.springframework.mapping.MappingException;
 
 public class SpelMapperTests {
@@ -147,7 +148,7 @@ public class SpelMapperTests {
 	}
 
 	@Test
-	public void mapBeanNestedCustomMapper() {
+	public void mapBeanNestedCustomNestedMapper() {
 		PersonDto source = new PersonDto();
 		NestedDto nested = new NestedDto();
 		nested.foo = "bar";
@@ -171,6 +172,31 @@ public class SpelMapperTests {
 		assertEquals("bar and baz", target.nested.foo);
 	}
 
+	@Test
+	public void mapBeanNestedCustomNestedMapperHandCoded() {
+		PersonDto source = new PersonDto();
+		NestedDto nested = new NestedDto();
+		nested.foo = "bar";
+		source.setNested(nested);
+
+		Person target = new Person();
+
+		Mapper nestedMapper = new Mapper<NestedDto, Nested>() {
+			public Object map(NestedDto source, Nested target) {
+				target.foo = source.foo + " and baz";
+				return target;
+			}
+
+		};
+		mapper.addNestedMapper(nestedMapper);
+
+		mapper.setAutoMappingEnabled(false);
+		mapper.addMapping("nested");
+		mapper.map(source, target);
+
+		assertEquals("bar and baz", target.nested.foo);
+	}
+
 	@Test
 	public void mapList() {
 		PersonDto source = new PersonDto();