private com.google.protobuf.SingleFieldBuilderV3<
              com.google.storagetransfer.v1.proto.TransferTypes.HttpData,
              com.google.storagetransfer.v1.proto.TransferTypes.HttpData.Builder,
              com.google.storagetransfer.v1.proto.TransferTypes.HttpDataOrBuilder>
          getHttpDataSourceFieldBuilder() {
        if (httpDataSourceBuilder_ == null) {
          if (!(dataSourceCase_ == 3)) {
            dataSource_ =
                com.google.storagetransfer.v1.proto.TransferTypes.HttpData.getDefaultInstance();
          }
          httpDataSourceBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.storagetransfer.v1.proto.TransferTypes.HttpData,
                  com.google.storagetransfer.v1.proto.TransferTypes.HttpData.Builder,
                  com.google.storagetransfer.v1.proto.TransferTypes.HttpDataOrBuilder>(
                  (com.google.storagetransfer.v1.proto.TransferTypes.HttpData) dataSource_,
                  getParentForChildren(),
                  isClean());
          dataSource_ = null;
        }
        dataSourceCase_ = 3;
        onChanged();
        return httpDataSourceBuilder_;
      }
<pre>
An HTTP URL data source.
</pre>

<code>.google.storagetransfer.v1.HttpData http_data_source = 3;</code>
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java