ConfigBootstrapper.java

class ConfigBootstrapper extends KeyedStateBootstrapFunction<String, TestConfig> {
        ValueState<Integer> threshold;

        @Override
        public void open(Configuration parameters) throws Exception {
            threshold = getRuntimeContext().getState(new ValueStateDescriptor<Integer>("thresholdState", Integer.class));
        }

        @Override
        public void processElement(TestConfig testConfig, Context context) throws Exception {
            threshold.update(testConfig.getThresholdValue());
        }
}