protected Supplier<Map<String,String>> buildDruidWebServiceHeaderSupplier(){
  Supplier<Map<String,String>> supplier=null;
  String customSupplierClassString=SYSTEM_CONFIG.getStringProperty(DRUID_HEADER_SUPPLIER_CLASS,null);
  if (customSupplierClassString != null && customSupplierClassString.equals("")) {
    try {
      Class<?> c=Class.forName(customSupplierClassString);
      Constructor<?> constructor=c.getConstructor();
      supplier=(Supplier<Map<String,String>>)constructor.newInstance();
    }
 catch (    Exception e) {
      LOG.error("Unable to load the Druid query header supplier, className: {}, exception: {}",customSupplierClassString,e);
      throw new IllegalStateException(e);
    }
  }
  return supplier;
}

protected Supplier < Map < String , String > > buildDruidWebServiceHeaderSupplier ( ) { Supplier < Map < String , String > > supplier = null ; String customSupplierClassString = SYSTEM_CONFIG . getStringProperty ( DRUID_HEADER_SUPPLIER_CLASS , null ) ; if ( customSupplierClassString != null && customSupplierClassString . equals ( "" ) ) { try { Class < ? > c = Class . forName ( customSupplierClassString ) ; Constructor < ? > constructor = c . getConstructor ( ) ; supplier = ( Supplier < Map < String , String > > ) constructor . newInstance ( ) ; } catch ( Exception e ) { LOG . error ( "Unable to load the Druid query header supplier, className: {}, exception: {}" , customSupplierClassString , e ) ; throw new IllegalStateException ( e ) ; } } return supplier ; }
build the supplier for druid data request headers .
