@java.lang.Override
  public long getParentSpanId() {
    return parentSpanId_;
  }
<pre>
Optional. ID of the parent span, if any.
</pre>

<code>fixed64 parent_span_id = 6 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The parentSpanId.
java-trace/proto-google-cloud-trace-v1/src/main/java/com/google/devtools/cloudtrace/v1/TraceSpan.java