/* * * SchemaCrawler * http://sourceforge.net/projects/schemacrawler * Copyright (c) 2000-2014, Sualeh Fatehi. * * This library is free software; you can redistribute it and/or modify it under the terms * of the GNU Lesser General Public License as published by the Free Software Foundation; * either version 2.1 of the License, or (at your option) any later version. * * This library 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License along with this * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. * */ package sf.util; import java.util.ArrayList; import java.util.HashMap; import java.util.List; public class Multimap<K, V> extends HashMap<K, List<V>> { private static final long serialVersionUID = 1470713639458689002L; public V add(final K key, final V value) { List<V> values = null; if (containsKey(key)) { values = get(key); } if (values == null) { values = new ArrayList<>(); } put(key, values); values.add(value); return value; } }