Relay your custom options to Dataflow, assuming your are using Flex Templates

RelayOptions.java

import org.apache.beam.runners.dataflow.options.DataflowPipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;


public static void main(String[] args) {
  PipelineOptions opts =
    PipelineOptionsFactory.fromArgs(args);

  DataflowPipelineOptions dataflowPipelineOptions =
    opts.as(DataflowPipelineOptions.class);
  
  if (opts.iWantStreamingEngine) {
    dataflowPipelineOptions.setEnableStreamingEngine(true);
  } else {
    dataflowPipelineOptions.setEnableStreamingEngine(false);
  }
 
  ...
}