| /* |
| * 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.car; |
| |
| import java.util.ArrayDeque; |
| import java.util.Iterator; |
| import java.util.function.Predicate; |
| import java.util.stream.Stream; |
| |
| /** |
| * This class keeps track of a limited fixed number of sample data points, correctly removing |
| * older samples as new ones are added, and it allows inspecting the samples, as well as |
| * easily answering N out of M questions. |
| */ |
| class SlidingWindow<T> implements Iterable<T> { |
| private final ArrayDeque<T> mElements; |
| private final int mMaxSize; |
| |
| public SlidingWindow(int size) { |
| mMaxSize = size; |
| mElements = new ArrayDeque<>(mMaxSize); |
| } |
| |
| public void add(T sample) { |
| if (mElements.size() == mMaxSize) { |
| mElements.removeFirst(); |
| } |
| mElements.addLast(sample); |
| } |
| |
| public void addAll(Iterable<T> elements) { |
| elements.forEach(this::add); |
| } |
| |
| @Override |
| public Iterator<T> iterator() { |
| return mElements.iterator(); |
| } |
| |
| public Stream<T> stream() { |
| return mElements.stream(); |
| } |
| |
| public int size() { |
| return mElements.size(); |
| } |
| |
| public int count(Predicate<T> predicate) { |
| return (int)stream().filter(predicate).count(); |
| } |
| } |