| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.android.collect; |
| |
| import android.annotation.UnsupportedAppUsage; |
| import android.util.ArraySet; |
| |
| import java.util.Collections; |
| import java.util.EnumSet; |
| import java.util.HashSet; |
| import java.util.SortedSet; |
| import java.util.TreeSet; |
| |
| /** |
| * Provides static methods for creating mutable {@code Set} instances easily and |
| * other static methods for working with Sets. |
| * |
| */ |
| public class Sets { |
| |
| /** |
| * Creates an empty {@code HashSet} instance. |
| * |
| * <p><b>Note:</b> if {@code E} is an {@link Enum} type, use {@link |
| * EnumSet#noneOf} instead. |
| * |
| * <p><b>Note:</b> if you only need an <i>immutable</i> empty Set, |
| * use {@link Collections#emptySet} instead. |
| * |
| * @return a newly-created, initially-empty {@code HashSet} |
| */ |
| @UnsupportedAppUsage |
| public static <K> HashSet<K> newHashSet() { |
| return new HashSet<K>(); |
| } |
| |
| /** |
| * Creates a {@code HashSet} instance containing the given elements. |
| * |
| * <p><b>Note:</b> due to a bug in javac 1.5.0_06, we cannot support the |
| * following: |
| * |
| * <p>{@code Set<Base> set = Sets.newHashSet(sub1, sub2);} |
| * |
| * <p>where {@code sub1} and {@code sub2} are references to subtypes of {@code |
| * Base}, not of {@code Base} itself. To get around this, you must use: |
| * |
| * <p>{@code Set<Base> set = Sets.<Base>newHashSet(sub1, sub2);} |
| * |
| * @param elements the elements that the set should contain |
| * @return a newly-created {@code HashSet} containing those elements (minus |
| * duplicates) |
| */ |
| @UnsupportedAppUsage |
| public static <E> HashSet<E> newHashSet(E... elements) { |
| int capacity = elements.length * 4 / 3 + 1; |
| HashSet<E> set = new HashSet<E>(capacity); |
| Collections.addAll(set, elements); |
| return set; |
| } |
| |
| /** |
| * Creates an empty {@code SortedSet} instance. |
| * |
| * @return a newly-created, initially-empty {@code SortedSet}. |
| */ |
| @UnsupportedAppUsage |
| public static <E> SortedSet<E> newSortedSet() { |
| return new TreeSet<E>(); |
| } |
| |
| /** |
| * Creates a {@code SortedSet} instance containing the given elements. |
| * |
| * @param elements the elements that the set should contain |
| * @return a newly-created {@code SortedSet} containing those elements (minus |
| * duplicates) |
| */ |
| public static <E> SortedSet<E> newSortedSet(E... elements) { |
| SortedSet<E> set = new TreeSet<E>(); |
| Collections.addAll(set, elements); |
| return set; |
| } |
| |
| /** |
| * Creates a {@code ArraySet} instance. |
| */ |
| @UnsupportedAppUsage |
| public static <E> ArraySet<E> newArraySet() { |
| return new ArraySet<E>(); |
| } |
| |
| /** |
| * Creates a {@code ArraySet} instance containing the given elements. |
| */ |
| @UnsupportedAppUsage |
| public static <E> ArraySet<E> newArraySet(E... elements) { |
| int capacity = elements.length * 4 / 3 + 1; |
| ArraySet<E> set = new ArraySet<E>(capacity); |
| Collections.addAll(set, elements); |
| return set; |
| } |
| } |