@Override public String toString() { String s = ""; for (int i = 0; i < items.size(); i++) { SearchConditionItem item = items.get(i); if (item instanceof SearchConditionGroupItem) { s += "(" + item.toString() + ")"; } else { s += item.toString(); } if (i != items.size()) { s += " " + this.getRelation() + " "; } } return s; }