Java tutorial
//package com.java2s; /** * Aptana Studio * Copyright (c) 2005-2011 by Appcelerator, Inc. All Rights Reserved. * Licensed under the terms of the GNU Public License (GPL) v3 (with exceptions). * Please see the license.html included with this distribution for details. * Any modifications to this file must keep this entire header intact. */ import java.util.ArrayList; import java.util.List; public class Main { /** * Convert a vararg list of items into a List. An empty list is returned if items is null * * @param <T> * Any type of object * @param items * A variable length list of items of type T * @return Returns a new ArrayList<T> or an empty list */ public static final <T> List<T> newList(T... items) { return addToList(new ArrayList<T>(items != null ? items.length : 0), items); } /** * Add a varargs list of items to the specified list. If the list or items array are null, then no action is * performed. Note that the destination list has no requirements other than it must be a List of the source item's * type. This allows the destination to be used, for example, as an accumulator.<br> * <br> * Note that this method is not thread safe. Users of this method will need to maintain type safety against the * list. * * @param list * A list to which items will be added * @param items * A list of items to add */ public static final <T, U extends T> List<T> addToList(List<T> list, U... items) { if (list != null && items != null) { for (int i = 0; i < items.length; i++) { list.add(items[i]); } if (list instanceof ArrayList) { ((ArrayList<T>) list).trimToSize(); } } return list; } /** * Add a varargs list of items to the specified list. If the list or items array are null, then no action is * performed. Note that the destination list has no requirements other than it must be a List of the source item's * type. This allows the destination to be used, for example, as an accumulator.<br> * <br> * Note that this method is not thread safe. Users of this method will need to maintain type safety against the * list. * * @param list * A list to which items will be added * @param items * A list of items to add */ public static final <T, U extends T> List<T> addToList(List<T> list, List<U> items) { if (list != null && items != null) { list.addAll(items); } return list; } }