public java.lang.String getOrderBy() {
      java.lang.Object ref = orderBy_;
      if (!(ref instanceof java.lang.String)) {
        com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
        java.lang.String s = bs.toStringUtf8();
        orderBy_ = s;
        return s;
      } else {
        return (java.lang.String) ref;
      }
    }
<pre>
Optional. The ordering applied to the [Executions.ListExecutions] results.
By default the ordering is based on descending start time.
The following fields are supported for order by:
executionID, startTime, endTime, duration, state, and workflowRevisionID.
</pre>

<code>string order_by = 6 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The orderBy.
java-workflow-executions/proto-google-cloud-workflow-executions-v1/src/main/java/com/google/cloud/workflows/executions/v1/ListExecutionsRequest.java