public void addAsAlternativeExportForVolume(URI volumeURI,URI exportMaskURI){
  Set<URI> alternatesForVolume=volumeToAlternativeMasks.get(volumeURI);
  if (alternatesForVolume == null) {
    alternatesForVolume=new HashSet<>();
    volumeToAlternativeMasks.put(volumeURI,alternatesForVolume);
  }
  alternatesForVolume.add(exportMaskURI);
}

public void addAsAlternativeExportForVolume ( URI volumeURI , URI exportMaskURI ) { Set < URI > alternatesForVolume = volumeToAlternativeMasks . get ( volumeURI ) ; if ( alternatesForVolume == null ) { alternatesForVolume = new HashSet < > ( ) ; volumeToAlternativeMasks . put ( volumeURI , alternatesForVolume ) ; } alternatesForVolume . add ( exportMaskURI ) ; }
associate that the volume , with given uri , can be potentially be placed into the exportmask , given by its uri .
