DATADOC-144 - Added @FieldName annotation to allow defining the name of the field a property shall be stored to.

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/mapping/BasicMongoPersistentProperty.java

@@ -21,6 +21,8 @@ import java.math.BigInteger;
 import java.util.HashSet;
 import java.util.Set;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.bson.types.ObjectId;
 import org.springframework.data.mapping.AnnotationBasedPersistentProperty;
 import org.springframework.data.mapping.model.Association;
@@ -34,6 +36,8 @@ import com.mongodb.DBObject;
  */
 public class BasicMongoPersistentProperty extends AnnotationBasedPersistentProperty<MongoPersistentProperty> implements
 		MongoPersistentProperty {
+	
+	private static final Log LOG = LogFactory.getLog(BasicMongoPersistentProperty.class);
 
 	private static final Set<Class<?>> SUPPORTED_ID_TYPES = new HashSet<Class<?>>();
 	private static final Set<String> SUPPORTED_ID_PROPERTY_NAMES = new HashSet<String>();
@@ -56,6 +60,10 @@ public class BasicMongoPersistentProperty extends AnnotationBasedPersistentPrope
 	 */
 	public BasicMongoPersistentProperty(Field field, PropertyDescriptor propertyDescriptor, MongoPersistentEntity<?> owner) {
 		super(field, propertyDescriptor, owner);
+		
+		if (isIdProperty() && field.isAnnotationPresent(FieldName.class)) {
+			LOG.warn(String.format("Invalid usage of %s on id property. Field name will not be considered!", FieldName.class));
+		}
 	}
 
 	/* (non-Javadoc)
@@ -87,7 +95,13 @@ public class BasicMongoPersistentProperty extends AnnotationBasedPersistentPrope
 	 * @return
 	 */
 	public String getKey() {
-		return isIdProperty() ? "_id" : getName();
+		
+		if (isIdProperty()) {
+			return "_id";
+		}
+		
+		FieldName annotation = getField().getAnnotation(FieldName.class);
+		return annotation != null ? annotation.value() : getName();
 	}
 
 	/* (non-Javadoc)

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/mapping/FieldName.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2011 by the original author(s).
+ *
+ * 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.document.mongodb.mapping;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation to allow defining the name of the field a property should use in a Mongo document. This will cause the
+ * property annotated being persisted to a field with the configured name as wells as being read from it.
+ * 
+ * @author Oliver Gierke
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.FIELD })
+public @interface FieldName {
+
+	String value();
+}

spring-data-mongodb/src/test/java/org/springframework/data/document/mongodb/mapping/BasicMongoPersistentPropertyUnitTests.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2011 by the original author(s).
+ *
+ * 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.document.mongodb.mapping;
+
+import static org.junit.Assert.*;
+import static org.hamcrest.CoreMatchers.*;
+import java.lang.reflect.Field;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.util.ClassTypeInformation;
+import org.springframework.util.ReflectionUtils;
+
+/**
+ * Unit test for {@link BasicMongoPersistentProperty}.
+ * 
+ * @author Oliver Gierke
+ */
+public class BasicMongoPersistentPropertyUnitTests {
+	
+	MongoPersistentEntity<Person> entity;
+	
+	@Before
+	public void setup() {
+		entity = new BasicMongoPersistentEntity<Person>(ClassTypeInformation.from(Person.class));
+	}
+
+	@Test
+	public void usesAnnotatedFieldName() {
+		
+		Field field = ReflectionUtils.findField(Person.class, "firstname");
+		assertThat(getPropertyFor(field).getKey(), is("foo"));
+	}
+	
+	@Test
+	public void returns_IdForIdProperty() {
+		Field field = ReflectionUtils.findField(Person.class, "id");
+		MongoPersistentProperty property = getPropertyFor(field);
+		assertThat(property.isIdProperty(), is(true));
+		assertThat(property.getKey(), is("_id"));
+	}
+	
+	@Test
+	public void returnsPropertyNameForUnannotatedProperties() {
+		
+		Field field = ReflectionUtils.findField(Person.class, "lastname");
+		assertThat(getPropertyFor(field).getKey(), is("lastname"));
+	}
+	
+	private MongoPersistentProperty getPropertyFor(Field field) {
+		return new BasicMongoPersistentProperty(field, null, entity);
+	}
+	
+	class Person {
+		
+		@Id
+		String id;
+		
+		@FieldName("foo")
+		String firstname;
+		String lastname;
+	}
+}

spring-data-mongodb/src/test/java/org/springframework/data/document/mongodb/mapping/MappingMongoConverterUnitTests.java

@@ -190,6 +190,33 @@ public class MappingMongoConverterUnitTests {
 		assertThat(result.sampleEnum, is(SampleEnum.FIRST));
 	}
 	
+	/**
+	 * @see DATADOC-144
+	 */
+	@Test
+	public void considersFieldNameWhenWriting() {
+		
+		Person person = new Person();
+		person.firstname ="Oliver";
+		
+		DBObject result = new BasicDBObject();
+		converter.write(person, result);
+		
+		assertThat(result.containsField("foo"), is(true));
+		assertThat(result.containsField("firstname"), is(false));
+	}
+	
+	/**
+	 * @see DATADOC-144
+	 */
+	@Test
+	public void considersFieldNameWhenReading() {
+		
+		DBObject dbObject = new BasicDBObject("foo", "Oliver");
+		Person result = converter.read(Person.class, dbObject);
+		
+		assertThat(result.firstname, is("Oliver"));
+	}
 	
 	class ClassWithEnumProperty {
 		
@@ -211,6 +238,9 @@ public class MappingMongoConverterUnitTests {
 
 	public static class Person implements Contact {
 		LocalDate birthDate;
+		
+		@FieldName("foo")
+		String firstname;
 	}
 
 	static class ClassWithMapProperty {