DATAMONGO-1538 - Polishing.

Use InheritingExposedFieldsAggregationOperationContext instead of anonymous context class. Drop aggregation input collections before tests. Minor reformatting.

Author: mp911de

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

@@ -28,7 +28,6 @@
 import org.springframework.data.mongodb.core.aggregation.AggregationExpressions.Filter.AsBuilder;
 import org.springframework.data.mongodb.core.aggregation.AggregationExpressions.Let.ExpressionVariable;
 import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
-import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
 import org.springframework.data.mongodb.core.query.CriteriaDefinition;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -3905,21 +3904,8 @@ public static AsBuilder filter(List<?> values) {
 		 */
 		@Override
 		public DBObject toDbObject(final AggregationOperationContext context) {
-
-			return toFilter(new ExposedFieldsAggregationOperationContext(ExposedFields.from(as), context) {
-
-				@Override
-				public FieldReference getReference(Field field) {
-
-					FieldReference ref = null;
-					try {
-						ref = context.getReference(field);
-					} catch (Exception e) {
-						// just ignore that one.
-					}
-					return ref != null ? ref : super.getReference(field);
-				}
-			});
+			return toFilter(
+					new InheritingExposedFieldsAggregationOperationContext(ExposedFields.from(as), context));
 		}
 
 		private DBObject toFilter(AggregationOperationContext context) {
@@ -6019,22 +6005,7 @@ public Map andApply(final AggregationExpression expression) {
 
 		@Override
 		public DBObject toDbObject(final AggregationOperationContext context) {
-
-			return toMap(new ExposedFieldsAggregationOperationContext(
-					ExposedFields.synthetic(Fields.fields(itemVariableName)), context) {
-
-				@Override
-				public FieldReference getReference(Field field) {
-
-					FieldReference ref = null;
-					try {
-						ref = context.getReference(field);
-					} catch (Exception e) {
-						// just ignore that one.
-					}
-					return ref != null ? ref : super.getReference(field);
-				}
-			});
+			return toMap(new InheritingExposedFieldsAggregationOperationContext(ExposedFields.synthetic(Fields.fields(itemVariableName)), context));
 		}
 
 		private DBObject toMap(AggregationOperationContext context) {
@@ -6792,22 +6763,7 @@ public interface LetBuilder {
 
 		@Override
 		public DBObject toDbObject(final AggregationOperationContext context) {
-
-			return toLet(new ExposedFieldsAggregationOperationContext(
-					ExposedFields.synthetic(Fields.fields(getVariableNames())), context) {
-
-				@Override
-				public FieldReference getReference(Field field) {
-
-					FieldReference ref = null;
-					try {
-						ref = context.getReference(field);
-					} catch (Exception e) {
-						// just ignore that one.
-					}
-					return ref != null ? ref : super.getReference(field);
-				}
-			});
+			return toLet(new InheritingExposedFieldsAggregationOperationContext(ExposedFields.synthetic(Fields.fields(getVariableNames())), context));
 		}
 
 		private String[] getVariableNames() {
@@ -6816,14 +6772,15 @@ private String[] getVariableNames() {
 			for (int i = 0; i < this.vars.size(); i++) {
 				varNames[i] = this.vars.get(i).variableName;
 			}
+
 			return varNames;
 		}
 
 		private DBObject toLet(AggregationOperationContext context) {
 
 			DBObject letExpression = new BasicDBObject();
-
 			DBObject mappedVars = new BasicDBObject();
+
 			for (ExpressionVariable var : this.vars) {
 				mappedVars.putAll(getMappedVariable(var, context));
 			}

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

@@ -13,17 +13,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package org.springframework.data.mongodb.core.aggregation;
 
 import org.springframework.data.mongodb.core.aggregation.ExposedFields.FieldReference;
-import org.springframework.util.Assert;
 
 /**
  * {@link ExposedFieldsAggregationOperationContext} that inherits fields from its parent
  * {@link AggregationOperationContext}.
  *
  * @author Mark Paluch
+ * @since 1.9
  */
 class InheritingExposedFieldsAggregationOperationContext extends ExposedFieldsAggregationOperationContext {
 
@@ -40,7 +39,7 @@ public InheritingExposedFieldsAggregationOperationContext(ExposedFields exposedF
 			AggregationOperationContext previousContext) {
 
 		super(exposedFields, previousContext);
-		Assert.notNull(previousContext, "PreviousContext must not be null!");
+
 		this.previousContext = previousContext;
 	}
 

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

@@ -143,6 +143,8 @@ private void cleanDb() {
 		mongoTemplate.dropCollection(MeterData.class);
 		mongoTemplate.dropCollection(LineItem.class);
 		mongoTemplate.dropCollection(InventoryItem.class);
+		mongoTemplate.dropCollection(Sales.class);
+		mongoTemplate.dropCollection(Sales2.class);
 	}
 
 	/**