From 9ed5e6886c172b3bc14c89de8bcd64956c0db9f6 Mon Sep 17 00:00:00 2001
From: Oliver Gierke <info@olivergierke.de>
Date: Tue, 26 Jul 2011 23:35:05 +0200
Subject: [PATCH] DATADOC-224 - Inspect value entity metadata in case it's a
 subtype of the declared property.

---
 .../core/convert/MappingMongoConverter.java   | 16 ++++++++--
 .../MappingMongoConverterUnitTests.java       | 29 +++++++++++++++++++
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
index bd2f9c340..3e39e8af2 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
@@ -440,9 +440,11 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 			return;
 		}
 
+		TypeInformation<?> type = prop.getTypeInformation();
+		
 		if (prop.isMap()) {
 			BasicDBObject mapDbObj = new BasicDBObject();
-			writeMapInternal((Map<Object, Object>) obj, mapDbObj, prop.getTypeInformation());
+			writeMapInternal((Map<Object, Object>) obj, mapDbObj, type);
 			dbo.put(name, mapDbObj);
 			return;
 		}
@@ -464,10 +466,18 @@ public class MappingMongoConverter extends AbstractMongoConverter implements App
 		}
 
 		BasicDBObject propDbObj = new BasicDBObject();
-		addCustomTypeKeyIfNecessary(prop.getTypeInformation(), obj, propDbObj);
-		writeInternal(obj, propDbObj, mappingContext.getPersistentEntity(prop.getTypeInformation()));
+		addCustomTypeKeyIfNecessary(type, obj, propDbObj);
+		
+		MongoPersistentEntity<?> entity = isSubtype(prop.getType(), obj.getClass()) ? mappingContext
+				.getPersistentEntity(obj.getClass()) : mappingContext.getPersistentEntity(type);
+		
+		writeInternal(obj, propDbObj, entity);
 		dbo.put(name, propDbObj);
 	}
+	
+	private boolean isSubtype(Class<?> left, Class<?> right) {
+		return left.isAssignableFrom(right) && !left.equals(right);
+	}
 
 	/**
 	 * Returns given object as {@link Collection}. Will return the {@link Collection} as is if the source is a
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java
index d6fa81839..154d0c347 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java
@@ -465,6 +465,35 @@ public class MappingMongoConverterUnitTests {
 		assertThat(converter.maybeConvertObject(null), is(nullValue()));
 	}
 	
+	@Test
+	public void writesGenericTypeCorrectly() {
+		
+		GenericType<Address> type = new GenericType<Address>();
+		type.content = new Address();
+		type.content.city = "London";
+		
+		BasicDBObject result = new BasicDBObject();
+		converter.write(type, result);
+		
+		DBObject content = (DBObject) result.get("content");
+		assertThat(content.get("_class"), is(notNullValue()));
+		assertThat(content.get("city"), is(notNullValue()));
+	}
+	
+	@Test
+	public void readsGenericTypeCorrectly() {
+		
+		DBObject address = new BasicDBObject("_class", Address.class.getName());
+		address.put("city", "London");
+		
+		GenericType<?> result = converter.read(GenericType.class, new BasicDBObject("content", address));
+		assertThat(result.content, is(instanceOf(Address.class)));
+		
+	}
+	
+	class GenericType<T> {
+		T content;
+	}
 	
 	class ClassWithEnumProperty {