public CollectionDragControl(Map<Node,List<Node>> groups,Function<Node,VisualItem> adapter,Function<VisualItem,VisualItem> aggAdapter){
  this.groups=Collections.unmodifiableMap(groups);
  this.aggAdapter=aggAdapter;
  this.adapter=adapter;
  dragged=false;
  selectedItem=null;
}

public CollectionDragControl ( Map < Node , List < Node > > groups , Function < Node , VisualItem > adapter , Function < VisualItem , VisualItem > aggAdapter ) { this . groups = Collections . unmodifiableMap ( groups ) ; this . aggAdapter = aggAdapter ; this . adapter = adapter ; dragged = false ; selectedItem = null ; }
creates a drag control with a copy of the provided map .
