@java.lang.Override
        public java.lang.String getNodeIdPrefix() {
          java.lang.Object ref = nodeIdPrefix_;
          if (ref instanceof java.lang.String) {
            return (java.lang.String) ref;
          } else {
            com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
            java.lang.String s = bs.toStringUtf8();
            nodeIdPrefix_ = s;
            return s;
          }
        }
<pre>
Prefix of node_ids in case of multi-node request
Should follow the `^[A-Za-z0-9_.~+%-]+$` regex format.
If node_count = 3 and node_id_prefix = "np", node ids of nodes
created will be "np-0", "np-1", "np-2". If this field is not
provided we use queued_resource_id as the node_id_prefix.
</pre>

<code>string node_id_prefix = 2;</code>

@return The nodeIdPrefix.
java-tpu/proto-google-cloud-tpu-v2alpha1/src/main/java/com/google/cloud/tpu/v2alpha1/QueuedResource.java