public void setSortBy(String sortBy) {
        this.sortBy = sortBy;
    }
<p>
The field that the result list is sorted by.
</p>
<p>
When you choose to sort by <code>serviceName</code>, service instances within each service are sorted by service
instance name.
</p>
<p>
Default: <code>serviceName</code>
</p>

@param sortBy
       The field that the result list is sorted by.</p>
       <p>
       When you choose to sort by <code>serviceName</code>, service instances within each service are sorted by
       service instance name.
       </p>
       <p>
       Default: <code>serviceName</code>
@see ListServiceInstancesSortBy
aws-java-sdk-proton/src/main/java/com/amazonaws/services/proton/model/ListServiceInstancesRequest.java