| /* |
| * Copyright (C) 2017 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.android.server.backup.utils; |
| |
| import android.util.SparseArray; |
| |
| import java.util.HashSet; |
| |
| /** |
| * Helper functions for manipulating instances of {@link SparseArray}. |
| */ |
| public final class SparseArrayUtils { |
| // Statics only |
| private SparseArrayUtils() {} |
| |
| /** |
| * Given a {@link SparseArray<HashSet>}, returns a new {@link HashSet} containing every element |
| * from every set in the array. |
| * |
| * @param sets The array of sets from which to take the union. |
| * @param <V> The type of element contained in the set. |
| * @return The complete set. |
| */ |
| public static<V> HashSet<V> union(SparseArray<HashSet<V>> sets) { |
| HashSet<V> unionSet = new HashSet<>(); |
| int n = sets.size(); |
| for (int i = 0; i < n; i++) { |
| HashSet<V> ithSet = sets.valueAt(i); |
| if (ithSet != null) { |
| unionSet.addAll(ithSet); |
| } |
| } |
| return unionSet; |
| } |
| } |