DATAMONGO-721 - Updates retain type information for collections properties.

Added test case to demonstrate that the fix for DATACMNS-345 will propagate into Spring Data MongoDB.

Original pull request: #52.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/QueryMapper.java

@@ -99,7 +99,7 @@ public class QueryMapper {
 				Keyword keyword = new Keyword((DBObject) rawValue);
 				result.put(newKey, getMappedKeyword(field, keyword));
 			} else {
-				result.put(newKey, getMappedValue(field, query.get(key)));
+				result.put(newKey, getMappedValue(field, rawValue));
 			}
 		}
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/UpdateMapperUnitTests.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.convert;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+import org.springframework.data.mongodb.MongoDbFactory;
+import org.springframework.data.mongodb.core.DBObjectUtils;
+import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
+import org.springframework.data.mongodb.core.query.Update;
+
+import com.mongodb.DBObject;
+
+/**
+ * Unit tests for {@link UpdateMapper}.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class UpdateMapperUnitTests {
+
+	@Mock MongoDbFactory factory;
+	MappingMongoConverter converter;
+	MongoMappingContext context;
+
+	@Before
+	public void setUp() {
+		context = new MongoMappingContext();
+		converter = new MappingMongoConverter(factory, context);
+	}
+
+	/**
+	 * @see DATAMONGO-721
+	 */
+	@Test
+	public void updateMapperRetainsTypeInformationForCollectionField() {
+
+		Update update = new Update().push("list", new ConcreteChildClass("2", "BAR"));
+		UpdateMapper mapper = new UpdateMapper(converter);
+
+		DBObject mappedObject = mapper.getMappedObject(update.getUpdateObject(),
+				context.getPersistentEntity(ParentClass.class));
+
+		DBObject push = DBObjectUtils.getAsDBObject(mappedObject, "$push");
+		DBObject list = DBObjectUtils.getAsDBObject(push, "list");
+
+		assertThat(list.get("_class"), is((Object) ConcreteChildClass.class.getName()));
+	}
+
+	static class ParentClass {
+
+		String id;
+		List<? extends AbstractChildClass> list;
+
+		public ParentClass(String id, List<? extends AbstractChildClass> list) {
+			this.id = id;
+			this.list = list;
+		}
+
+	}
+
+	static abstract class AbstractChildClass {
+
+		String id;
+		String value;
+
+		public AbstractChildClass(String id, String value) {
+			this.id = id;
+			this.value = value;
+		}
+	}
+
+	static class ConcreteChildClass extends AbstractChildClass {
+
+		public ConcreteChildClass(String id, String value) {
+			super(id, value);
+		}
+	}
+}