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.android.car.internal.util; 18 19 import android.util.ArraySet; 20 21 import java.util.Collections; 22 import java.util.EnumSet; 23 import java.util.HashSet; 24 import java.util.SortedSet; 25 import java.util.TreeSet; 26 27 // Copy from frameworks/base/core/java/com/google/android/collect 28 29 /** 30 * Provides static methods for creating mutable {@code Set} instances easily and 31 * other static methods for working with Sets. 32 * 33 * @hide 34 */ 35 public class Sets { 36 /** 37 * Creates an empty {@code HashSet} instance. 38 * 39 * <p><b>Note:</b> if {@code E} is an {@link Enum} type, use {@link 40 * EnumSet#noneOf} instead. 41 * 42 * <p><b>Note:</b> if you only need an <i>immutable</i> empty Set, 43 * use {@link Collections#emptySet} instead. 44 * 45 * @return a newly-created, initially-empty {@code HashSet} 46 */ newHashSet()47 public static <K> HashSet<K> newHashSet() { 48 return new HashSet<K>(); 49 } 50 51 /** 52 * Creates a {@code HashSet} instance containing the given elements. 53 * 54 * <p><b>Note:</b> due to a bug in javac 1.5.0_06, we cannot support the 55 * following: 56 * 57 * <p>{@code Set<Base> set = Sets.newHashSet(sub1, sub2);} 58 * 59 * <p>where {@code sub1} and {@code sub2} are references to subtypes of {@code 60 * Base}, not of {@code Base} itself. To get around this, you must use: 61 * 62 * <p>{@code Set<Base> set = Sets.<Base>newHashSet(sub1, sub2);} 63 * 64 * @param elements the elements that the set should contain 65 * @return a newly-created {@code HashSet} containing those elements (minus 66 * duplicates) 67 */ newHashSet(E... elements)68 public static <E> HashSet<E> newHashSet(E... elements) { 69 int capacity = elements.length * 4 / 3 + 1; 70 HashSet<E> set = new HashSet<E>(capacity); 71 Collections.addAll(set, elements); 72 return set; 73 } 74 75 /** 76 * Creates an empty {@code SortedSet} instance. 77 * 78 * @return a newly-created, initially-empty {@code SortedSet}. 79 */ newSortedSet()80 public static <E> SortedSet<E> newSortedSet() { 81 return new TreeSet<E>(); 82 } 83 84 /** 85 * Creates a {@code SortedSet} instance containing the given elements. 86 * 87 * @param elements the elements that the set should contain 88 * @return a newly-created {@code SortedSet} containing those elements (minus 89 * duplicates) 90 */ newSortedSet(E... elements)91 public static <E> SortedSet<E> newSortedSet(E... elements) { 92 SortedSet<E> set = new TreeSet<E>(); 93 Collections.addAll(set, elements); 94 return set; 95 } 96 97 /** 98 * Creates a {@code ArraySet} instance. 99 */ newArraySet()100 public static <E> ArraySet<E> newArraySet() { 101 return new ArraySet<E>(); 102 } 103 104 /** 105 * Creates a {@code ArraySet} instance containing the given elements. 106 */ newArraySet(E... elements)107 public static <E> ArraySet<E> newArraySet(E... elements) { 108 int capacity = elements.length * 4 / 3 + 1; 109 ArraySet<E> set = new ArraySet<E>(capacity); 110 Collections.addAll(set, elements); 111 return set; 112 } 113 } 114