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