001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.management.mbean;
018
019/**
020 * Holds the loads averaged over 1min, 5min, and 15min.
021 */
022public final class LoadTriplet {
023
024    // Exponents for EWMA: exp(-INTERVAL / WINDOW) (in seconds)
025    private static final double EXP_1 = Math.exp(-1 / (60.0 * 1.0));
026    private static final double EXP_5 = Math.exp(-1 / (60.0 * 5.0));
027    private static final double EXP_15 = Math.exp(-1 / (60.0 * 15.0));
028
029    private double load01 = Double.NaN;
030    private double load05 = Double.NaN;
031    private double load15 = Double.NaN;
032
033    /**
034     * Update the load statistics
035     *
036     * @param currentReading the current reading
037     */
038    public void update(int currentReading) {
039        load01 = updateLoad(currentReading, EXP_1, load01);
040        load05 = updateLoad(currentReading, EXP_5, load05);
041        load15 = updateLoad(currentReading, EXP_15, load15);
042    }
043
044    private double updateLoad(int reading, double exp, double recentLoad) {
045        return Double.isNaN(recentLoad) ? reading : reading + exp * (recentLoad - reading);
046    }
047
048    public double getLoad1() {
049        return load01;
050    }
051
052    public double getLoad5() {
053        return load05;
054    }
055
056    public double getLoad15() {
057        return load15;
058    }
059
060    @Override
061    public String toString() {
062        return String.format("%.2f, %.2f, %.2f", getLoad1(), getLoad5(), getLoad15());
063    }
064
065}