Make ClientInsertOneResult.getInsertedId return Optional

JAVA-5527

Author: stIncMale

driver-core/src/main/com/mongodb/client/result/bulk/ClientInsertOneResult.java

@@ -18,10 +18,11 @@
 import com.mongodb.annotations.Evolving;
 import com.mongodb.bulk.WriteConcernError;
 import com.mongodb.client.model.bulk.ClientWriteModel;
-import com.mongodb.lang.Nullable;
 import org.bson.BsonValue;
 import org.bson.RawBsonDocument;
 
+import java.util.Optional;
+
 /**
  * The result of a successful {@linkplain ClientWriteModel individual insert one operation}.
  * Note that {@link WriteConcernError}s are not considered as making individuals operations unsuccessful.
@@ -33,10 +34,10 @@ public interface ClientInsertOneResult {
     /**
      * The {@code "_id"} of the inserted document.
      *
-     * @return The {@code "_id"} of the inserted document, or {@code null} if one is not available,
-     * which happens when a {@link RawBsonDocument} without {@code "_id"} is inserted,
-     * because the driver does not generate missing {@code "_id"} fields for {@link RawBsonDocument}s.
+     * @return The {@code "_id"} of the inserted document.
+     * {@linkplain Optional#isPresent() Present} unless a {@link RawBsonDocument} is inserted,
+     * because the driver neither generates the missing {@code "_id"} field for a {@link RawBsonDocument},
+     * nor does it read the {@code "_id"} field from a {@link RawBsonDocument} when inserting it.
      */
-    @Nullable
-    BsonValue getInsertedId();
+    Optional<BsonValue> getInsertedId();
 }

driver-core/src/main/com/mongodb/internal/client/result/bulk/ConcreteClientInsertOneResult.java

@@ -20,6 +20,9 @@
 import org.bson.BsonValue;
 
 import java.util.Objects;
+import java.util.Optional;
+
+import static java.util.Optional.ofNullable;
 
 /**
  * This class is not part of the public API and may be removed or changed at any time.
@@ -33,9 +36,8 @@ public ConcreteClientInsertOneResult(@Nullable final BsonValue insertedId) {
     }
 
     @Override
-    @Nullable
-    public BsonValue getInsertedId() {
-        return insertedId;
+    public Optional<BsonValue> getInsertedId() {
+        return ofNullable(insertedId);
     }
 
     @Override