DATAMONGO-1893 - Polishing.

Inherit fields from previous operation if at least one field is excluded. Extend FieldsExposingAggregationOperation to conditionally inherit fields.

Backport to Java 6 code.

Original pull request: #538.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2018 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.
@@ -60,7 +60,7 @@ class AggregationOperationRenderer {
 				FieldsExposingAggregationOperation exposedFieldsOperation = (FieldsExposingAggregationOperation) operation;
 				ExposedFields fields = exposedFieldsOperation.getFields();
 
-				if (operation instanceof InheritsFieldsAggregationOperation) {
+				if (operation instanceof InheritsFieldsAggregationOperation || exposedFieldsOperation.inheritsFields()) {
 					contextToUse = new InheritingExposedFieldsAggregationOperationContext(fields, contextToUse);
 				} else {
 					contextToUse = fields.exposesNoFields() ? DEFAULT_CONTEXT

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2018 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.
@@ -169,6 +169,14 @@ public abstract class BucketOperationSupport<T extends BucketOperationSupport<T,
 		return outputs.asExposedFields();
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+		return false;
+	}
+
 	/**
 	 * Implementation hook to create a new bucket operation.
 	 *

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2018 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.
@@ -62,6 +62,14 @@ public class CountOperation implements FieldsExposingAggregationOperation {
 		return ExposedFields.from(new ExposedField(fieldName, true));
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+		return false;
+	}
+
 	/**
 	 * Builder for {@link CountOperation}.
 	 *

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2017 the original author or authors.
+ * Copyright 2016-2018 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.
@@ -96,6 +96,14 @@ public class FacetOperation implements FieldsExposingAggregationOperation {
 		return facets.asExposedFields();
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+		return false;
+	}
+
 	/**
 	 * Builder for {@link FacetOperation} by adding existing and the new pipeline of {@link AggregationOperation} to the
 	 * new {@link FacetOperation}.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2016 the original author or authors.
+ * Copyright 2013-2018 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.
@@ -34,10 +34,13 @@ public interface FieldsExposingAggregationOperation extends AggregationOperation
 	ExposedFields getFields();
 
 	/**
-	 * Marker interface for {@link AggregationOperation} that inherits fields from previous operations.
+	 * @return {@literal true} to conditionally inherit fields from previous operations.
+	 * @since 1.10.12
 	 */
-	static interface InheritsFieldsAggregationOperation extends FieldsExposingAggregationOperation {
-
-	}
+	boolean inheritsFields();
 
+	/**
+	 * Marker interface for {@link AggregationOperation} that inherits fields from previous operations.
+	 */
+	static interface InheritsFieldsAggregationOperation extends FieldsExposingAggregationOperation {}
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2017 the original author or authors.
+ * Copyright 2016-2018 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.
@@ -132,6 +132,14 @@ public class GraphLookupOperation implements InheritsFieldsAggregationOperation
 		return ExposedFields.from(new ExposedField(as, true));
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+		return true;
+	}
+
 	/**
 	 * @author Mark Paluch
 	 */

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 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.
@@ -32,7 +32,7 @@ import com.mongodb.DBObject;
  * <p>
  * We recommend to use the static factory method {@link Aggregation#group(Fields)} instead of creating instances of this
  * class directly.
- * 
+ *
  * @author Sebastian Herold
  * @author Thomas Darimont
  * @author Oliver Gierke
@@ -53,7 +53,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Creates a new {@link GroupOperation} including the given {@link Fields}.
-	 * 
+	 *
 	 * @param fields must not be {@literal null}.
 	 */
 	public GroupOperation(Fields fields) {
@@ -64,7 +64,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Creates a new {@link GroupOperation} from the given {@link GroupOperation}.
-	 * 
+	 *
 	 * @param groupOperation must not be {@literal null}.
 	 */
 	protected GroupOperation(GroupOperation groupOperation) {
@@ -73,7 +73,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Creates a new {@link GroupOperation} from the given {@link GroupOperation} and the given {@link Operation}s.
-	 * 
+	 *
 	 * @param groupOperation
 	 * @param nextOperations
 	 */
@@ -90,7 +90,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Creates a new {@link GroupOperation} from the current one adding the given {@link Operation}.
-	 * 
+	 *
 	 * @param operation must not be {@literal null}.
 	 * @return
 	 */
@@ -100,7 +100,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Builder for {@link GroupOperation}s on a field.
-	 * 
+	 *
 	 * @author Thomas Darimont
 	 */
 	public static final class GroupOperationBuilder {
@@ -110,7 +110,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Creates a new {@link GroupOperationBuilder} from the given {@link GroupOperation} and {@link Operation}.
-		 * 
+		 *
 		 * @param groupOperation
 		 * @param operation
 		 */
@@ -125,7 +125,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Allows to specify an alias for the new-operation operation.
-		 * 
+		 *
 		 * @param alias
 		 * @return
 		 */
@@ -139,7 +139,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 	 * <p>
 	 * Count expressions are emulated via {@code $sum: 1}.
 	 * <p>
-	 * 
+	 *
 	 * @return
 	 */
 	public GroupOperationBuilder count() {
@@ -148,7 +148,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for a {@code $sum}-expression for the given field-reference.
-	 * 
+	 *
 	 * @param reference
 	 * @return
 	 */
@@ -177,7 +177,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $add_to_set}-expression for the given field-reference.
-	 * 
+	 *
 	 * @param reference
 	 * @return
 	 */
@@ -187,7 +187,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $add_to_set}-expression for the given value.
-	 * 
+	 *
 	 * @param value
 	 * @return
 	 */
@@ -201,7 +201,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $last}-expression for the given field-reference.
-	 * 
+	 *
 	 * @param reference
 	 * @return
 	 */
@@ -212,7 +212,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $last}-expression for the given
 	 * {@link AggregationExpression}.
-	 * 
+	 *
 	 * @param expr
 	 * @return
 	 */
@@ -222,7 +222,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for a {@code $first}-expression for the given field-reference.
-	 * 
+	 *
 	 * @param reference
 	 * @return
 	 */
@@ -233,7 +233,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 	/**
 	 * Generates an {@link GroupOperationBuilder} for a {@code $first}-expression for the given
 	 * {@link AggregationExpression}.
-	 * 
+	 *
 	 * @param expr
 	 * @return
 	 */
@@ -243,7 +243,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $avg}-expression for the given field-reference.
-	 * 
+	 *
 	 * @param reference
 	 * @return
 	 */
@@ -254,7 +254,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $avg}-expression for the given
 	 * {@link AggregationExpression}.
-	 * 
+	 *
 	 * @param expr
 	 * @return
 	 */
@@ -264,7 +264,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $push}-expression for the given field-reference.
-	 * 
+	 *
 	 * @param reference
 	 * @return
 	 */
@@ -274,7 +274,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $push}-expression for the given value.
-	 * 
+	 *
 	 * @param value
 	 * @return
 	 */
@@ -288,7 +288,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $min}-expression that for the given field-reference.
-	 * 
+	 *
 	 * @param reference
 	 * @return
 	 */
@@ -299,7 +299,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $min}-expression that for the given
 	 * {@link AggregationExpression}.
-	 * 
+	 *
 	 * @param expr
 	 * @return
 	 */
@@ -309,7 +309,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $max}-expression that for the given field-reference.
-	 * 
+	 *
 	 * @param reference
 	 * @return
 	 */
@@ -320,7 +320,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 	/**
 	 * Generates an {@link GroupOperationBuilder} for an {@code $max}-expression that for the given
 	 * {@link AggregationExpression}.
-	 * 
+	 *
 	 * @param expr
 	 * @return
 	 */
@@ -379,7 +379,7 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 		return new GroupOperationBuilder(this, new Operation(keyword, null, reference, value));
 	}
 
-	/* 
+	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperationContext#getFields()
 	 */
@@ -395,6 +395,14 @@ public class GroupOperation implements FieldsExposingAggregationOperation {
 		return fields;
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+		return false;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2017 the original author or authors.
+ * Copyright 2016-2018 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.
@@ -73,6 +73,14 @@ public class LookupOperation implements FieldsExposingAggregationOperation, Inhe
 		return ExposedFields.from(as);
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+		return true;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 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.
@@ -40,20 +40,19 @@ import com.mongodb.DBObject;
  * <p>
  * We recommend to use the static factory method {@link Aggregation#project(Fields)} instead of creating instances of
  * this class directly.
- * 
+ *
  * @author Tobias Trelle
  * @author Thomas Darimont
  * @author Oliver Gierke
  * @author Christoph Strobl
  * @author Mark Paluch
  * @since 1.3
- * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/project/">MongoDB Aggregation Framework: $project</a>
+ * @see <a href="https://docs.mongodb.com/manual/reference/operator/aggregation/project/">MongoDB Aggregation Framework:
+ *      $project</a>
  */
 public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	private static final List<Projection> NONE = Collections.emptyList();
-	private static final String EXCLUSION_ERROR = "Exclusion of field %s not allowed. Projections by the mongodb "
-			+ "aggregation framework only support the exclusion of the %s field!";
 
 	private final List<Projection> projections;
 
@@ -66,7 +65,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Creates a new {@link ProjectionOperation} including the given {@link Fields}.
-	 * 
+	 *
 	 * @param fields must not be {@literal null}.
 	 */
 	public ProjectionOperation(Fields fields) {
@@ -76,7 +75,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 	/**
 	 * Copy constructor to allow building up {@link ProjectionOperation} instances from already existing
 	 * {@link Projection}s.
-	 * 
+	 *
 	 * @param current must not be {@literal null}.
 	 * @param projections must not be {@literal null}.
 	 */
@@ -92,7 +91,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Creates a new {@link ProjectionOperation} with the current {@link Projection}s and the given one.
-	 * 
+	 *
 	 * @param projection must not be {@literal null}.
 	 * @return
 	 */
@@ -103,7 +102,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 	/**
 	 * Creates a new {@link ProjectionOperation} with the current {@link Projection}s replacing the last current one with
 	 * the given one.
-	 * 
+	 *
 	 * @param projection must not be {@literal null}.
 	 * @return
 	 */
@@ -116,7 +115,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Creates a new {@link ProjectionOperationBuilder} to define a projection for the field with the given name.
-	 * 
+	 *
 	 * @param name must not be {@literal null} or empty.
 	 * @return
 	 */
@@ -134,7 +133,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Excludes the given fields from the projection.
-	 * 
+	 *
 	 * @param fieldNames must not be {@literal null}.
 	 * @return
 	 */
@@ -146,7 +145,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Includes the given fields into the projection.
-	 * 
+	 *
 	 * @param fieldNames must not be {@literal null}.
 	 * @return
 	 */
@@ -158,7 +157,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Includes the given fields into the projection.
-	 * 
+	 *
 	 * @param fields must not be {@literal null}.
 	 * @return
 	 */
@@ -183,6 +182,25 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		return fields;
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+
+		for (Projection projection : projections) {
+			if (projection instanceof FieldProjection) {
+
+				if (((FieldProjection) projection).isExcluded()) {
+					return true;
+				}
+			}
+		}
+
+		return false;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
@@ -201,7 +219,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Base class for {@link ProjectionOperationBuilder}s.
-	 * 
+	 *
 	 * @author Thomas Darimont
 	 */
 	private static abstract class AbstractProjectionOperationBuilder implements AggregationOperation {
@@ -211,7 +229,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Creates a new {@link AbstractProjectionOperationBuilder} fot the given value and {@link ProjectionOperation}.
-		 * 
+		 *
 		 * @param value must not be {@literal null}.
 		 * @param operation must not be {@literal null}.
 		 */
@@ -224,7 +242,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 			this.operation = operation;
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.mongodb.core.aggregation.AggregationOperation#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
 		 */
@@ -235,7 +253,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Returns the finally to be applied {@link ProjectionOperation} with the given alias.
-		 * 
+		 *
 		 * @param alias will never be {@literal null} or empty.
 		 * @return
 		 */
@@ -262,7 +280,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * An {@link ProjectionOperationBuilder} that is used for SpEL expression based projections.
-	 * 
+	 *
 	 * @author Thomas Darimont
 	 */
 	public static class ExpressionProjectionOperationBuilder extends ProjectionOperationBuilder {
@@ -273,7 +291,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Creates a new {@link ExpressionProjectionOperationBuilder} for the given value, {@link ProjectionOperation} and
 		 * parameters.
-		 * 
+		 *
 		 * @param expression must not be {@literal null}.
 		 * @param operation must not be {@literal null}.
 		 * @param parameters
@@ -321,7 +339,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * A {@link Projection} based on a SpEL expression.
-		 * 
+		 *
 		 * @author Thomas Darimont
 		 * @author Oliver Gierke
 		 */
@@ -334,7 +352,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 			/**
 			 * Creates a new {@link ExpressionProjection} for the given field, SpEL expression and parameters.
-			 * 
+			 *
 			 * @param field must not be {@literal null}.
 			 * @param expression must not be {@literal null} or empty.
 			 * @param parameters must not be {@literal null}.
@@ -350,7 +368,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 				this.params = parameters.clone();
 			}
 
-			/* 
+			/*
 			 * (non-Javadoc)
 			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
 			 */
@@ -368,7 +386,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Builder for {@link ProjectionOperation}s on a field.
-	 * 
+	 *
 	 * @author Oliver Gierke
 	 * @author Thomas Darimont
 	 * @author Christoph Strobl
@@ -384,7 +402,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Creates a new {@link ProjectionOperationBuilder} for the field with the given name on top of the given
 		 * {@link ProjectionOperation}.
-		 * 
+		 *
 		 * @param name must not be {@literal null} or empty.
 		 * @param operation must not be {@literal null}.
 		 * @param previousProjection the previous operation projection, may be {@literal null}.
@@ -400,7 +418,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Creates a new {@link ProjectionOperationBuilder} for the field with the given value on top of the given
 		 * {@link ProjectionOperation}.
-		 * 
+		 *
 		 * @param value
 		 * @param operation
 		 * @param previousProjection
@@ -417,7 +435,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Projects the result of the previous operation onto the current field. Will automatically add an exclusion for
 		 * {@code _id} as what would be held in it by default will now go into the field just projected into.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperation previousOperation() {
@@ -428,7 +446,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Defines a nested field binding for the current field.
-		 * 
+		 *
 		 * @param fields must not be {@literal null}.
 		 * @return
 		 */
@@ -438,7 +456,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Allows to specify an alias for the previous projection operation.
-		 * 
+		 *
 		 * @param alias
 		 * @return
 		 */
@@ -480,7 +498,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Generates an {@code $add} expression that adds the given number to the previously mentioned field.
-		 * 
+		 *
 		 * @param number
 		 * @return
 		 */
@@ -492,7 +510,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Generates an {@code $add} expression that adds the value of the given field to the previously mentioned field.
-		 * 
+		 *
 		 * @param fieldReference
 		 * @return
 		 */
@@ -504,7 +522,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Generates an {@code $subtract} expression that subtracts the given number to the previously mentioned field.
-		 * 
+		 *
 		 * @param number
 		 * @return
 		 */
@@ -517,7 +535,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Generates an {@code $subtract} expression that subtracts the value of the given field to the previously mentioned
 		 * field.
-		 * 
+		 *
 		 * @param fieldReference
 		 * @return
 		 */
@@ -543,7 +561,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Generates an {@code $multiply} expression that multiplies the given number with the previously mentioned field.
-		 * 
+		 *
 		 * @param number
 		 * @return
 		 */
@@ -556,7 +574,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Generates an {@code $multiply} expression that multiplies the value of the given field with the previously
 		 * mentioned field.
-		 * 
+		 *
 		 * @param fieldReference
 		 * @return
 		 */
@@ -582,7 +600,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Generates an {@code $divide} expression that divides the previously mentioned field by the given number.
-		 * 
+		 *
 		 * @param number
 		 * @return
 		 */
@@ -596,7 +614,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Generates an {@code $divide} expression that divides the value of the given field by the previously mentioned
 		 * field.
-		 * 
+		 *
 		 * @param fieldReference
 		 * @return
 		 */
@@ -623,7 +641,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Generates an {@code $mod} expression that divides the previously mentioned field by the given number and returns
 		 * the remainder.
-		 * 
+		 *
 		 * @param number
 		 * @return
 		 */
@@ -1232,7 +1250,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Adds a generic projection for the current field.
-		 * 
+		 *
 		 * @param operation the operation key, e.g. {@code $add}.
 		 * @param values the values to be set for the projection operation.
 		 * @return
@@ -1245,7 +1263,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * A {@link Projection} to pull in the result of the previous operation.
-		 * 
+		 *
 		 * @author Oliver Gierke
 		 */
 		static class PreviousOperationProjection extends Projection {
@@ -1254,7 +1272,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 			/**
 			 * Creates a new {@link PreviousOperationProjection} for the field with the given name.
-			 * 
+			 *
 			 * @param name must not be {@literal null} or empty.
 			 */
 			public PreviousOperationProjection(String name) {
@@ -1262,7 +1280,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 				this.name = name;
 			}
 
-			/* 
+			/*
 			 * (non-Javadoc)
 			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
 			 */
@@ -1274,7 +1292,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * A {@link FieldProjection} to map a result of a previous {@link AggregationOperation} to a new field.
-		 * 
+		 *
 		 * @author Oliver Gierke
 		 * @author Thomas Darimont
 		 * @author Mark Paluch
@@ -1286,7 +1304,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 			/**
 			 * Creates a new {@link FieldProjection} for the field of the given name, assigning the given value.
-			 * 
+			 *
 			 * @param name must not be {@literal null} or empty.
 			 * @param value
 			 */
@@ -1305,7 +1323,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 			/**
 			 * Factory method to easily create {@link FieldProjection}s for the given {@link Fields}. Fields are projected as
 			 * references with their given name. A field {@code foo} will be projected as: {@code foo : 1 } .
-			 * 
+			 *
 			 * @param fields the {@link Fields} to in- or exclude, must not be {@literal null}.
 			 * @return
 			 */
@@ -1315,7 +1333,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 			/**
 			 * Factory method to easily create {@link FieldProjection}s for the given {@link Fields}.
-			 * 
+			 *
 			 * @param fields the {@link Fields} to in- or exclude, must not be {@literal null}.
 			 * @param value to use for the given field.
 			 * @return
@@ -1332,7 +1350,14 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 				return projections;
 			}
 
-			/* 
+			/**
+			 * @return {@literal true} if this field is excluded.
+			 */
+			public boolean isExcluded() {
+				return Boolean.FALSE.equals(value);
+			}
+
+			/*
 			 * (non-Javadoc)
 			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
 			 */
@@ -1371,7 +1396,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 			/**
 			 * Creates a new {@link OperationProjection} for the given field.
-			 * 
+			 *
 			 * @param field the name of the field to add the operation projection for, must not be {@literal null} or empty.
 			 * @param operation the actual operation key, must not be {@literal null} or empty.
 			 * @param values the values to pass into the operation, must not be {@literal null}.
@@ -1425,7 +1450,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 			/**
 			 * Returns the field that holds the {@link OperationProjection}.
-			 * 
+			 *
 			 * @return
 			 */
 			protected Field getField() {
@@ -1448,7 +1473,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 			/**
 			 * Creates a new instance of this {@link OperationProjection} with the given alias.
-			 * 
+			 *
 			 * @param alias the alias to set
 			 * @return
 			 */
@@ -1489,7 +1514,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 				this.fields = fields;
 			}
 
-			/* 
+			/*
 			 * (non-Javadoc)
 			 * @see org.springframework.data.mongodb.core.aggregation.ProjectionOperation.Projection#toDBObject(org.springframework.data.mongodb.core.aggregation.AggregationOperationContext)
 			 */
@@ -1508,7 +1533,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the minute from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractMinute() {
@@ -1517,7 +1542,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the hour from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractHour() {
@@ -1526,7 +1551,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the second from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractSecond() {
@@ -1535,7 +1560,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the millisecond from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractMillisecond() {
@@ -1544,7 +1569,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the year from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractYear() {
@@ -1553,7 +1578,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the month from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractMonth() {
@@ -1562,7 +1587,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the week from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractWeek() {
@@ -1571,7 +1596,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the dayOfYear from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractDayOfYear() {
@@ -1580,7 +1605,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the dayOfMonth from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractDayOfMonth() {
@@ -1589,7 +1614,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Extracts the dayOfWeek from a date expression.
-		 * 
+		 *
 		 * @return
 		 */
 		public ProjectionOperationBuilder extractDayOfWeek() {
@@ -1599,7 +1624,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 	/**
 	 * Base class for {@link Projection} implementations.
-	 * 
+	 *
 	 * @author Oliver Gierke
 	 */
 	private static abstract class Projection {
@@ -1608,7 +1633,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Creates new {@link Projection} for the given {@link Field}.
-		 * 
+		 *
 		 * @param field must not be {@literal null}.
 		 */
 		public Projection(Field field) {
@@ -1619,7 +1644,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 
 		/**
 		 * Returns the field exposed by the {@link Projection}.
-		 * 
+		 *
 		 * @return will never be {@literal null}.
 		 */
 		public ExposedField getExposedField() {
@@ -1629,7 +1654,7 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 		/**
 		 * Renders the current {@link Projection} into a {@link DBObject} based on the given
 		 * {@link AggregationOperationContext}.
-		 * 
+		 *
 		 * @param context will never be {@literal null}.
 		 * @return
 		 */
@@ -1639,14 +1664,14 @@ public class ProjectionOperation implements FieldsExposingAggregationOperation {
 	/**
 	 * @author Thomas Darimont
 	 */
-	static class ExpressionProjection extends Projection {
+	static class ExpressionProjection extends ProjectionOperation.Projection {
 
 		private final AggregationExpression expression;
 		private final Field field;
 
 		/**
 		 * Creates a new {@link ExpressionProjection}.
-		 * 
+		 *
 		 * @param field
 		 * @param expression
 		 */

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2017 the original author or authors.
+ * Copyright 2016-2018 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.
@@ -95,6 +95,14 @@ public class ReplaceRootOperation implements FieldsExposingAggregationOperation
 		return ExposedFields.from();
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+		return false;
+	}
+
 	/**
 	 * Builder for {@link ReplaceRootOperation}.
 	 *

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

@@ -26,7 +26,7 @@ import com.mongodb.DBObject;
  * <p>
  * We recommend to use the static factory method {@link Aggregation#unwind(String)} instead of creating instances of
  * this class directly.
- * 
+ *
  * @author Thomas Darimont
  * @author Oliver Gierke
  * @author Mark Paluch
@@ -117,6 +117,14 @@ public class UnwindOperation
 		return arrayIndex != null ? ExposedFields.from(arrayIndex) : ExposedFields.from();
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.mongodb.core.aggregation.FieldsExposingAggregationOperation#inheritsFields()
+	 */
+	@Override
+	public boolean inheritsFields() {
+		return true;
+	}
+
 	/**
 	 * Get a builder that allows creation of {@link LookupOperation}.
 	 *

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 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.
@@ -211,9 +211,19 @@ public class ProjectionOperationUnitTests {
 	public void excludeShouldAllowExclusionOfFieldsOtherThanUnderscoreId/* since MongoDB 3.4 */() {
 
 		ProjectionOperation projectionOp = new ProjectionOperation().andExclude("foo");
-		Document document = projectionOp.toDocument(Aggregation.DEFAULT_CONTEXT);
-		Document projectClause = DocumentTestUtils.getAsDocument(document, PROJECT);
-		assertThat((Integer) projectClause.get("foo")).isEqualTo(0);
+		DBObject document = projectionOp.toDBObject(Aggregation.DEFAULT_CONTEXT);
+		DBObject projectClause = DBObjectTestUtils.getAsDBObject(document, PROJECT);
+
+		assertThat(projectionOp.inheritsFields(), is(true));
+		assertThat((Integer) projectClause.get("foo"), is(0));
+	}
+
+	@Test // DATAMONGO-1893
+	public void includeShouldNotInheritFields() {
+
+		ProjectionOperation projectionOp = new ProjectionOperation().andInclude("foo");
+
+		assertThat(projectionOp.inheritsFields(), is(false));
 	}
 
 	@Test // DATAMONGO-758
@@ -1548,14 +1558,13 @@ public class ProjectionOperationUnitTests {
 						.andApply(AggregationFunctionExpressions.MULTIPLY.of(Fields.field("total"), Fields.field("discounted")))) //
 				.as("finalTotal").toDBObject(Aggregation.DEFAULT_CONTEXT);
 
-		assertThat(agg,
-				is(JSON.parse("{ $project:{  \"finalTotal\" : { \"$let\": {" + //
-						"\"vars\": {" + //
-						"\"total\": { \"$add\": [ \"$price\", \"$tax\" ] }," + //
-						"\"discounted\": { \"$cond\": { \"if\": \"$applyDiscount\", \"then\": 0.9, \"else\": 1.0 } }" + //
-						"}," + //
-						"\"in\": { \"$multiply\": [ \"$$total\", \"$$discounted\" ] }" + //
-						"}}}}")));
+		assertThat(agg, is(JSON.parse("{ $project:{  \"finalTotal\" : { \"$let\": {" + //
+				"\"vars\": {" + //
+				"\"total\": { \"$add\": [ \"$price\", \"$tax\" ] }," + //
+				"\"discounted\": { \"$cond\": { \"if\": \"$applyDiscount\", \"then\": 0.9, \"else\": 1.0 } }" + //
+				"}," + //
+				"\"in\": { \"$multiply\": [ \"$$total\", \"$$discounted\" ] }" + //
+				"}}}}")));
 	}
 
 	@Test // DATAMONGO-1538
@@ -1572,14 +1581,13 @@ public class ProjectionOperationUnitTests {
 						AggregationFunctionExpressions.MULTIPLY.of(Fields.field("total"), Fields.field("discounted")))
 				.as("finalTotal").toDBObject(Aggregation.DEFAULT_CONTEXT);
 
-		assertThat(agg,
-				is(JSON.parse("{ $project:{ \"finalTotal\" : { \"$let\": {" + //
-						"\"vars\": {" + //
-						"\"total\": { \"$add\": [ \"$price\", \"$tax\" ] }," + //
-						"\"discounted\": { \"$cond\": { \"if\": \"$applyDiscount\", \"then\": 0.9, \"else\": 1.0 } }" + //
-						"}," + //
-						"\"in\": { \"$multiply\": [ \"$$total\", \"$$discounted\" ] }" + //
-						"}}}}")));
+		assertThat(agg, is(JSON.parse("{ $project:{ \"finalTotal\" : { \"$let\": {" + //
+				"\"vars\": {" + //
+				"\"total\": { \"$add\": [ \"$price\", \"$tax\" ] }," + //
+				"\"discounted\": { \"$cond\": { \"if\": \"$applyDiscount\", \"then\": 0.9, \"else\": 1.0 } }" + //
+				"}," + //
+				"\"in\": { \"$multiply\": [ \"$$total\", \"$$discounted\" ] }" + //
+				"}}}}")));
 	}
 
 	@Test // DATAMONGO-1548

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 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.
@@ -22,6 +22,8 @@ import static org.springframework.data.mongodb.core.aggregation.Aggregation.*;
 import static org.springframework.data.mongodb.core.aggregation.Fields.*;
 import static org.springframework.data.mongodb.test.util.IsBsonObject.*;
 
+import lombok.AllArgsConstructor;
+
 import java.util.Arrays;
 import java.util.List;
 
@@ -34,7 +36,7 @@ import org.mockito.runners.MockitoJUnitRunner;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.convert.support.GenericConversionService;
 import org.springframework.data.annotation.Id;
-import org.springframework.data.annotation.PersistenceConstructor;
+import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Sort.Direction;
 import org.springframework.data.mapping.model.MappingException;
 import org.springframework.data.mongodb.core.aggregation.ExposedFields.DirectFieldReference;
@@ -196,6 +198,20 @@ public class TypeBasedAggregationOperationContextUnitTests {
 						.containing("age", "$age.value"));
 	}
 
+	@Test // DATAMONGO-1893
+	public void considersIncludedFieldsFromSingleExclusionsCorrectly() {
+
+		AggregationOperationContext context = getContext(FooPerson.class);
+		TypedAggregation<FooPerson> agg = newAggregation(FooPerson.class, project() //
+				.andExclude("name"), sort(new Sort("age.value", "lastName")));
+
+		DBObject dbo = agg.toDbObject("person", context);
+
+		DBObject sort = getPipelineElementFromAggregationAt(dbo, 1);
+		assertThat(getAsDBObject(sort, "$sort"),
+				is(equalTo((DBObject) new BasicDBObject("age.value", 1).append("last_name", 1))));
+	}
+
 	@Test // DATAMONGO-1133
 	public void shouldHonorAliasedFieldsInGroupExpressions() {
 
@@ -352,18 +368,13 @@ public class TypeBasedAggregationOperationContextUnitTests {
 	}
 
 	@Document(collection = "person")
+	@AllArgsConstructor
 	public static class FooPerson {
 
 		final ObjectId id;
 		final String name;
+		@org.springframework.data.mongodb.core.mapping.Field("last_name") final String lastName;
 		final Age age;
-
-		@PersistenceConstructor
-		FooPerson(ObjectId id, String name, Age age) {
-			this.id = id;
-			this.name = name;
-			this.age = age;
-		}
 	}
 
 	public static class Age {