Add ClientMetadata entity.

JAVA-5854

driver-core/src/main/com/mongodb/internal/connection/ClientMetadata.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2008-present MongoDB, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.mongodb.internal.connection;
+
+import com.mongodb.MongoDriverInformation;
+import com.mongodb.lang.Nullable;
+import org.bson.BsonDocument;
+
+import static com.mongodb.internal.connection.ClientMetadataHelper.createClientMetadataDocument;
+import static com.mongodb.internal.connection.ClientMetadataHelper.updateClientMedataDocument;
+
+/**
+ * Represents metadata of the current MongoClient.
+ *
+ * <p>This class is not part of the public API and may be removed or changed at any time</p>
+ */
+public class ClientMetadata {
+    private volatile BsonDocument clientMetadataBsonDocument;
+
+    public ClientMetadata(@Nullable final String applicationName, final MongoDriverInformation mongoDriverInformation) {
+        this.clientMetadataBsonDocument = createClientMetadataDocument(applicationName, mongoDriverInformation);
+    }
+
+    /**
+     * Returns mutable BsonDocument that represents the client metadata.
+     */
+    public BsonDocument getBsonDocument() {
+        return clientMetadataBsonDocument;
+    }
+
+    public void append(final MongoDriverInformation mongoDriverInformation) {
+        this.clientMetadataBsonDocument = updateClientMedataDocument(clientMetadataBsonDocument, mongoDriverInformation);
+    }
+}
+

driver-core/src/main/com/mongodb/internal/connection/InternalStreamConnectionFactory.java

@@ -42,8 +42,8 @@ class InternalStreamConnectionFactory implements InternalConnectionFactory {
     private final MongoCredentialWithCache credential;
 
     InternalStreamConnectionFactory(final ClusterConnectionMode clusterConnectionMode,
-            final StreamFactory streamFactory,
-            @Nullable final MongoCredentialWithCache credential,
+                                    final StreamFactory streamFactory,
+                                    @Nullable final MongoCredentialWithCache credential,
                                     final ClientMetadata clientMetadata,
             final List<MongoCompressor> compressorList,
             final LoggerSettings loggerSettings, @Nullable final CommandListener commandListener, @Nullable final ServerApi serverApi) {
@@ -52,8 +52,8 @@ class InternalStreamConnectionFactory implements InternalConnectionFactory {
     }
 
     InternalStreamConnectionFactory(final ClusterConnectionMode clusterConnectionMode, final boolean isMonitoringConnection,
-            final StreamFactory streamFactory,
-            @Nullable final MongoCredentialWithCache credential,
+                                    final StreamFactory streamFactory,
+                                    @Nullable final MongoCredentialWithCache credential,
                                     final ClientMetadata clientMetadata,
             final List<MongoCompressor> compressorList,
             final LoggerSettings loggerSettings, @Nullable final CommandListener commandListener, @Nullable final ServerApi serverApi) {
@@ -72,7 +72,7 @@ class InternalStreamConnectionFactory implements InternalConnectionFactory {
     public InternalConnection create(final ServerId serverId, final ConnectionGenerationSupplier connectionGenerationSupplier) {
         Authenticator authenticator = credential == null ? null : createAuthenticator(credential);
         InternalStreamConnectionInitializer connectionInitializer = new InternalStreamConnectionInitializer(
-                clusterConnectionMode, authenticator, clientMetadata.getClientMetadataBsonDocument(), compressorList, serverApi);
+                clusterConnectionMode, authenticator, clientMetadata.getBsonDocument(), compressorList, serverApi);
         return new InternalStreamConnection(
                 clusterConnectionMode, authenticator,
                 isMonitoringConnection, serverId, connectionGenerationSupplier,

driver-core/src/test/functional/com/mongodb/internal/connection/ClientMetadataHelperProseTest.java

@@ -341,6 +341,7 @@ void testUpdateClientMetadataDocument() {
                 .driverPlatform("JDK 99")
                 .build();
 
+        //We pass metadataToAppend to a builder and prepend with initial driver information.
         MongoDriverInformation expectedUpdatedMetadata = MongoDriverInformation.builder(metadataToAppend)
                 .driverName("mongo-spark")
                 .driverVersion("2.0.0")