From 9147ccdda99cc77a47c109dcdf84a9fcedb98548 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20G=C5=82=C3=B3wka?= <maciejglowka.pl@gmail.com>
Date: Tue, 24 Aug 2021 04:44:47 +0200
Subject: [PATCH] BAEL-4889: checking whether a field exists or not in MongoDB
 (#11129)

* BAEL-4889: checking whether a field exists or not in MongoDB

* BAEL-4889: fixed test class name

* BAEL-4889: upgraded mongo version

* BAEL-4889: changed test class name
---
 persistence-modules/java-mongodb/pom.xml      |  2 +-
 .../FieldExistenceLiveTest.java               | 50 +++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 persistence-modules/java-mongodb/src/test/java/com/baeldung/existence.field/FieldExistenceLiveTest.java

diff --git a/persistence-modules/java-mongodb/pom.xml b/persistence-modules/java-mongodb/pom.xml
index 15d904b12c..f708a54f46 100644
--- a/persistence-modules/java-mongodb/pom.xml
+++ b/persistence-modules/java-mongodb/pom.xml
@@ -33,7 +33,7 @@
     </dependencies>
 
     <properties>
-        <mongo.version>3.10.1</mongo.version>
+        <mongo.version>3.12.1</mongo.version>
         <flapdoodle.version>1.11</flapdoodle.version>
         <morphia.version>1.5.3</morphia.version>
     </properties>
diff --git a/persistence-modules/java-mongodb/src/test/java/com/baeldung/existence.field/FieldExistenceLiveTest.java b/persistence-modules/java-mongodb/src/test/java/com/baeldung/existence.field/FieldExistenceLiveTest.java
new file mode 100644
index 0000000000..ca37ac6664
--- /dev/null
+++ b/persistence-modules/java-mongodb/src/test/java/com/baeldung/existence.field/FieldExistenceLiveTest.java
@@ -0,0 +1,50 @@
+package com.baeldung.existence.field;
+
+import com.mongodb.BasicDBObject;
+import com.mongodb.MongoClient;
+import com.mongodb.client.MongoCollection;
+import com.mongodb.client.MongoDatabase;
+import com.mongodb.client.model.Filters;
+import org.bson.Document;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class FieldExistenceLiveTest {
+    private MongoClient mongoClient;
+    private MongoDatabase db;
+    private MongoCollection<Document> collection;
+
+    @Before
+    public void setup() {
+        if (mongoClient == null) {
+            mongoClient = new MongoClient();
+            db = mongoClient.getDatabase("existence");
+            collection = db.getCollection("users");
+            collection.insertOne(Document.parse("{'name':'Ben','surname': 'Big'}"));
+        }
+    }
+
+    @Test
+    public void givenMongoCollection_whenUsingFilters_thenCheckingForExistingFieldWorks() {
+        Document nameDoc = collection.find(Filters.exists("name")).first();
+        assertNotNull(nameDoc);
+        assertFalse(nameDoc.isEmpty());
+
+        nameDoc = collection.find(Filters.exists("non_existing")).first();
+        assertNull(nameDoc);
+    }
+
+    @Test
+    public void givenMongoCollection_whenUsingStandardDocumentQuery_thenCheckingForExistingFieldWorks() {
+        Document query = new Document("name", new BasicDBObject("$exists", true));
+        Document doc = collection.find(query).first();
+        assertNotNull(doc);
+        assertFalse(doc.isEmpty());
+
+        query = new Document("non_existing", new BasicDBObject("$exists", true));
+        doc = collection.find(query).first();
+        assertNull(doc);
+    }
+}