1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.android.collect; 18 19 import android.compat.annotation.UnsupportedAppUsage; 20 21 import java.util.ArrayList; 22 import java.util.Collections; 23 24 /** 25 * Provides static methods for creating {@code List} instances easily, and other 26 * utility methods for working with lists. 27 */ 28 public class Lists { 29 30 /** 31 * Creates an empty {@code ArrayList} instance. 32 * 33 * <p><b>Note:</b> if you only need an <i>immutable</i> empty List, use 34 * {@link Collections#emptyList} instead. 35 * 36 * @return a newly-created, initially-empty {@code ArrayList} 37 */ 38 @UnsupportedAppUsage newArrayList()39 public static <E> ArrayList<E> newArrayList() { 40 return new ArrayList<E>(); 41 } 42 43 /** 44 * Creates a resizable {@code ArrayList} instance containing the given 45 * elements. 46 * 47 * <p><b>Note:</b> due to a bug in javac 1.5.0_06, we cannot support the 48 * following: 49 * 50 * <p>{@code List<Base> list = Lists.newArrayList(sub1, sub2);} 51 * 52 * <p>where {@code sub1} and {@code sub2} are references to subtypes of 53 * {@code Base}, not of {@code Base} itself. To get around this, you must 54 * use: 55 * 56 * <p>{@code List<Base> list = Lists.<Base>newArrayList(sub1, sub2);} 57 * 58 * @param elements the elements that the list should contain, in order 59 * @return a newly-created {@code ArrayList} containing those elements 60 */ 61 @UnsupportedAppUsage newArrayList(E... elements)62 public static <E> ArrayList<E> newArrayList(E... elements) { 63 int capacity = (elements.length * 110) / 100 + 5; 64 ArrayList<E> list = new ArrayList<E>(capacity); 65 Collections.addAll(list, elements); 66 return list; 67 } 68 } 69