void (Object object) { if (object instanceof String) { for (HistoryElement element : history) { if (object.equals(element.expression)) { object = element; break; } } } if (object instanceof String) { object = selectedItem.changeExpression((String)object); } if (selectedItem != null && selectedItem != object || selectedItem == null && object != null) { selectedItem = (HistoryElement)object; fireContentsChanged(this, -1, -1); } }