Implementation:Datahub project Datahub ProtobufOneOfField

Knowledge Sources	Datahub_project_Datahub
Domains	Protobuf_Integration, Schema_Modeling
Last Updated	2026-02-10 00:00 GMT

Overview

Description

ProtobufOneOfField is a model class that represents a Protocol Buffer oneof field within the DataHub protobuf schema integration. It extends ProtobufField and overrides key methods to provide union-type semantics. The class maps protobuf oneof declarations to DataHub's UnionType schema field type, using the fixed native type string "oneof" and field path type "[type=union]".

The comment extraction logic filters source code locations for ONEOF_DECL_FIELD_NUMBER path entries to locate the specific documentation associated with the oneof declaration.

Usage

Instantiated during protobuf schema graph construction when a oneof declaration is encountered. Participates in the visitor pattern to contribute union-type schema fields to the DataHub metadata output.

Code Reference

Source Location

metadata-integration/java/datahub-protobuf/src/main/java/datahub/protobuf/model/ProtobufOneOfField.java

Signature

@Getter
public class ProtobufOneOfField extends ProtobufField {

    public static final String NATIVE_TYPE = "oneof";
    public static final String FIELD_PATH_TYPE = "[type=union]";

    @Builder(builderMethodName = "oneOfBuilder")
    public ProtobufOneOfField(ProtobufMessage protobufMessage, FieldDescriptorProto fieldProto)

    public String name()
    public String fieldPathType()
    public String nativeType()
    public boolean isMessage()
    public SchemaFieldDataType schemaFieldDataType()
    public String comment()
}

Import

import datahub.protobuf.model.ProtobufOneOfField;

I/O Contract

Inputs

Parameter	Type	Description
protobufMessage	ProtobufMessage	The parent message containing this oneof declaration
fieldProto	FieldDescriptorProto	The field descriptor proto for one of the fields in the oneof

Outputs

Method	Return Type	Description
name()	String	The name of the oneof declaration (from oneOfProto().getName())
fieldPathType()	String	Always returns "[type=union]"
nativeType()	String	Always returns "oneof"
isMessage()	boolean	Always returns false
schemaFieldDataType()	SchemaFieldDataType	Returns a UnionType schema field data type
comment()	String	Extracted comments for the oneof declaration from source code info

Usage Examples

ProtobufOneOfField oneOf = ProtobufOneOfField.oneOfBuilder()
    .protobufMessage(parentMessage)
    .fieldProto(fieldDescriptorProto)
    .build();

String name = oneOf.name();                         // e.g., "value_type"
SchemaFieldDataType type = oneOf.schemaFieldDataType(); // UnionType
String pathType = oneOf.fieldPathType();             // "[type=union]"

Related Pages

• Datahub_project_Datahub_ProtobufMessage -- Parent message model
• Datahub_project_Datahub_ProtobufDescriptorUtils -- Used for comment collapsing
• Datahub_project_Datahub_ProtobufExtensionFieldVisitor -- Visits fields including oneof fields