Here you can find the source of unionAdd(List
This method adds obj to vect if and only if vect does not already contain obj.
public static <E> void unionAdd(List<E> vect, E obj)
//package com.java2s; /*/*from w w w .j av a2 s .c o m*/ VectorUtils.java Convenience methods for working with Lists.. provides efficient Union, Intersection, and Difference methods. Created: 21 July 1998 Module By: Jonathan Abbey, jonabbey@arlut.utexas.edu ----------------------------------------------------------------------- Directory Directory Management System Copyright (C) 1996-2012 The University of Texas at Austin Ganymede is a registered trademark of The University of Texas at Austin Contact information Web site: http://www.arlut.utexas.edu/gash2 Author Email: ganymede_author@arlut.utexas.edu Email mailing list: ganymede@arlut.utexas.edu US Mail: Computer Science Division Applied Research Laboratories The University of Texas at Austin PO Box 8029, Austin TX 78713-8029 Telephone: (512) 835-3200 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ import java.util.List; public class Main { /** * <p>This method adds obj to vect if and only if vect does not * already contain obj.</p> */ public static <E> void unionAdd(List<E> vect, E obj) { if (obj == null) { return; } if (vect.contains(obj)) { return; } vect.add(obj); } }