DATAMONGO-2637 - Fields and projection API are very inconvenient

Author: divyajnu08

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/aggregation/Fields.java

@@ -233,14 +233,9 @@ public AggregationField(String name, @Nullable String target) {
 			String targetToSet = target != null ? cleanUp(target) : null;
 
 			Assert.hasText(nameToSet, "AggregationField name must not be null or empty!");
-
-			if (target == null && name.contains(".")) {
-				this.name = nameToSet.substring(nameToSet.indexOf('.') + 1);
-				this.target = nameToSet;
-			} else {
-				this.name = nameToSet;
-				this.target = targetToSet;
-			}
+			
+			this.name = nameToSet;
+			this.target = target == null ? nameToSet : targetToSet; 
 		}
 
 		private static String cleanUp(String source) {

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/aggregation/ProjectionOperationUnitTests.java

@@ -2255,6 +2255,34 @@ void nestedMappedFieldReferenceInArrayField() {
 		assertThat(doc).isEqualTo(Document.parse(
 				"{ $project: { \"author\" : 1,  \"myArray\" : [ \"$ti_t_le\", \"plain - string\", { \"$sum\" : [\"$ti_t_le\", 10] } ] } } ] }"));
 	}
+	
+	@Test
+	void withNestedFieldsIncludeProjection(){
+
+		Document doc = new ProjectionOperation()
+				.andInclude("foo")
+				.andInclude("foo.bar")
+				.andInclude("foo.bar.baz")
+				.toDocument(Aggregation.DEFAULT_CONTEXT);
+
+		assertThat(doc).isEqualTo(Document.parse(
+				"{\"$project\" : {\"foo\" : 1, \"foo.bar\" : 1, \"foo.bar.baz\" : 1}}"));
+		
+	}
+	
+	@Test
+	void withNestedFieldsExcludeProjection(){
+
+		Document doc = new ProjectionOperation()
+				.andExclude("foo")
+				.andExclude("foo.bar")
+				.andExclude("foo.bar.baz")
+				.toDocument(Aggregation.DEFAULT_CONTEXT);
+
+		assertThat(doc).isEqualTo(Document.parse(
+				"{\"$project\" : {\"foo\" : 0, \"foo.bar\" : 0, \"foo.bar.baz\" : 0}}"));
+		
+	}
 
 	private static Document extractOperation(String field, Document fromProjectClause) {
 		return (Document) fromProjectClause.get(field);