DATAMONGO-1548 - Add support for MongoDB 3.4 aggregation operators.

We now support the following MongoDB 3.4 aggregation operators:

$indexOfBytes, $indexOfCP, $split, $strLenBytes, $strLenCP, $substrCP, $indexOfArray, $range, $reverseArray, $reduce, $zip, $in, $isoDayOfWeek, $isoWeek, $isoWeekYear, $switch and $type.

Original pull request: #423.

Author: christophstrobl

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

@@ -22,6 +22,7 @@
 import java.util.List;
 
 import org.springframework.data.mongodb.core.aggregation.ExposedFields.ExposedField;
+import org.springframework.data.mongodb.core.aggregation.Fields.AggregationField;
 import org.springframework.util.Assert;
 import org.springframework.util.CompositeIterator;
 import org.springframework.util.ObjectUtils;
@@ -406,6 +407,11 @@ public Object getReferenceValue() {
 		 */
 		@Override
 		public String toString() {
+
+			if(getRaw().startsWith("$")) {
+				return getRaw();
+			}
+
 			return String.format("$%s", getRaw());
 		}
 

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

@@ -187,20 +187,21 @@ public Iterator<Field> iterator() {
 	}
 
 	/**
-	 *
 	 * @return
 	 * @since 1.10
 	 */
 	public List<Field> asList() {
 		return Collections.unmodifiableList(fields);
 	}
+
 	/**
 	 * Value object to encapsulate a field in an aggregation operation.
 	 * 
 	 * @author Oliver Gierke
 	 */
 	static class AggregationField implements Field {
 
+		private final String raw;
 		private final String name;
 		private final String target;
 
@@ -225,6 +226,7 @@ public AggregationField(String name) {
 		 */
 		public AggregationField(String name, String target) {
 
+			raw = name;
 			String nameToSet = cleanUp(name);
 			String targetToSet = cleanUp(target);
 
@@ -266,6 +268,11 @@ public String getName() {
 		 * @see org.springframework.data.mongodb.core.aggregation.Field#getAlias()
 		 */
 		public String getTarget() {
+
+			if (isLocalVar()) {
+				return this.getRaw();
+			}
+
 			return StringUtils.hasText(this.target) ? this.target : this.name;
 		}
 
@@ -278,6 +285,22 @@ public boolean isAliased() {
 			return !getName().equals(getTarget());
 		}
 
+		/**
+		 * @return {@literal true} in case the field name starts with {@code $$}.
+		 * @since 1.10
+		 */
+		public boolean isLocalVar() {
+			return raw.startsWith("$$") && !raw.startsWith("$$$");
+		}
+
+		/**
+		 * @return
+		 * @since 1.10
+		 */
+		public String getRaw() {
+			return raw;
+		}
+
 		/* 
 		 * (non-Javadoc)
 		 * @see java.lang.Object#toString()

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

@@ -491,8 +491,10 @@ protected Object convert(AggregationExpressionTransformationContext<MethodRefere
 			} else if (ObjectUtils.nullSafeEquals(methodReference.getArgumentType(), ArgumentType.MAP)) {
 
 				DBObject dbo = new BasicDBObject();
-				for (int i = 0; i < methodReference.getArgumentMap().length; i++) {
-					dbo.put(methodReference.getArgumentMap()[i], transform(node.getChild(i), context));
+
+				int i = 0;
+				for(ExpressionNode child : node) {
+					dbo.put(methodReference.getArgumentMap()[i++], transform(child, context));
 				}
 				args = dbo;
 			} else {

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

@@ -90,6 +90,12 @@ public class MethodReferenceNode extends ExpressionNode {
 		map.put("toLower", singleArgumentAggregationMethodReference().forOperator("$toLower"));
 		map.put("toUpper", singleArgumentAggregationMethodReference().forOperator("$toUpper"));
 		map.put("strcasecmp", arrayArgumentAggregationMethodReference().forOperator("$strcasecmp"));
+		map.put("indexOfBytes", arrayArgumentAggregationMethodReference().forOperator("$indexOfBytes"));
+		map.put("indexOfCP", arrayArgumentAggregationMethodReference().forOperator("$indexOfCP"));
+		map.put("split", arrayArgumentAggregationMethodReference().forOperator("$split"));
+		map.put("strLenBytes", singleArgumentAggregationMethodReference().forOperator("$strLenBytes"));
+		map.put("strLenCP", singleArgumentAggregationMethodReference().forOperator("$strLenCP"));
+		map.put("substrCP", arrayArgumentAggregationMethodReference().forOperator("$substrCP"));
 
 		// TEXT SEARCH OPERATORS
 		map.put("meta", singleArgumentAggregationMethodReference().forOperator("$meta"));
@@ -102,6 +108,12 @@ public class MethodReferenceNode extends ExpressionNode {
 		map.put("isArray", singleArgumentAggregationMethodReference().forOperator("$isArray"));
 		map.put("size", singleArgumentAggregationMethodReference().forOperator("$size"));
 		map.put("slice", arrayArgumentAggregationMethodReference().forOperator("$slice"));
+		map.put("reverseArray", singleArgumentAggregationMethodReference().forOperator("$reverseArray"));
+		map.put("reduce", mapArgumentAggregationMethodReference().forOperator("$reduce").mappingParametersTo("input",
+				"initialValue", "in"));
+		map.put("zip", mapArgumentAggregationMethodReference().forOperator("$zip").mappingParametersTo("inputs",
+				"useLongestLength", "defaults"));
+		map.put("in", arrayArgumentAggregationMethodReference().forOperator("$in"));
 
 		// VARIABLE OPERATORS
 		map.put("map", mapArgumentAggregationMethodReference().forOperator("$map") //
@@ -124,6 +136,9 @@ public class MethodReferenceNode extends ExpressionNode {
 		map.put("millisecond", singleArgumentAggregationMethodReference().forOperator("$millisecond"));
 		map.put("dateToString", mapArgumentAggregationMethodReference().forOperator("$dateToString") //
 				.mappingParametersTo("format", "date"));
+		map.put("isoDayOfWeek", singleArgumentAggregationMethodReference().forOperator("$isoDayOfWeek"));
+		map.put("isoWeek", singleArgumentAggregationMethodReference().forOperator("$isoWeek"));
+		map.put("isoWeekYear", singleArgumentAggregationMethodReference().forOperator("$isoWeekYear"));
 
 		// CONDITIONAL OPERATORS
 		map.put("cond", mapArgumentAggregationMethodReference().forOperator("$cond") //
@@ -142,6 +157,9 @@ public class MethodReferenceNode extends ExpressionNode {
 		map.put("stdDevPop", arrayArgumentAggregationMethodReference().forOperator("$stdDevPop"));
 		map.put("stdDevSamp", arrayArgumentAggregationMethodReference().forOperator("$stdDevSamp"));
 
+		// TYPE OPERATORS
+		map.put("type", singleArgumentAggregationMethodReference().forOperator("$type"));
+
 		FUNCTIONS = Collections.unmodifiableMap(map);
 	}