/** * Returns a formatted string version of this set Examples: If set contains "a" and "b", this * method should return the string "{a, b}". If the set is empty, this method should return the * string "{}". */ public String toString() { String result = "{"; if (size() > 0) result += data.get(0); for (int i = 1; i < data.size(); i++) result += ", " + data.get(i); return result + "}"; }
/** * Removes e from the set, and throws an IllegalArgumentException if e is null * * @param e */ public void remove(String e) { if (e == null) throw new IllegalArgumentException(); for (int i = 0; i < data.size(); i++) { if (data.get(i).equals(e)) { data.remove(i); break; } } }
/** * Indicates whether the set contains e, and throws an IllegalArgumentException if e is null. * * @param e * @return true if the set contains e */ public boolean contains(String e) { if (e == null) throw new IllegalArgumentException(); boolean exist = false; for (int i = 0; i < data.size(); i++) { if (data.get(i).equals(e)) { exist = true; } } return exist; }