Create aggregate method

Signed-off-by: Otavio Santana <[email protected]>

Author: otaviojava

mongodb-driver/src/main/java/org/eclipse/jnosql/communication/mongodb/document/MongoDBDocumentCollectionManager.java

@@ -15,6 +15,7 @@
 
 package org.eclipse.jnosql.communication.mongodb.document;
 
+import com.mongodb.client.AggregateIterable;
 import com.mongodb.client.FindIterable;
 import com.mongodb.client.MongoCollection;
 import com.mongodb.client.MongoDatabase;
@@ -33,6 +34,9 @@
 import org.eclipse.jnosql.communication.document.Documents;
 
 import java.time.Duration;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
@@ -175,8 +179,24 @@ public long delete(String collectionName, Bson filter) {
         return result.getDeletedCount();
     }
 
-    public long aggregate(String collectionName, Bson filter) {
-        return 0L;
+    /**
+     * Aggregates documents according to the specified aggregation pipeline.
+     *
+     * @param collectionName the collection name
+     * @param pipeline the aggregation pipeline
+     * @return the number of documents deleted.
+     * @throws NullPointerException when filter or collectionName is null
+     */
+    public Map<String, Object> aggregate(String collectionName, List<Bson> pipeline) {
+        Objects.requireNonNull(pipeline, "filter is required");
+        Objects.requireNonNull(collectionName, "collectionName is required");
+        MongoCollection<Document> collection = mongoDatabase.getCollection(collectionName);
+        AggregateIterable<Document> aggregate = collection.aggregate(pipeline);
+        for (Document document : aggregate) {
+            BsonDocument bson = document.toBsonDocument();
+            System.out.println(bson);
+        }
+        return Collections.emptyMap();
     }
 
     /**