CpuManagementSysmon.java

/**
 * This file is part of Waarp Project.
 * 
 * Copyright 2009, Frederic Bregier, and individual contributors by the @author tags. See the
 * COPYRIGHT.txt in the distribution for a full listing of individual contributors.
 * 
 * All Waarp Project is free software: you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 * 
 * Waarp is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along with Waarp . If not, see
 * <http://www.gnu.org/licenses/>.
 */
package org.waarp.common.cpu;

import com.jezhumble.javasysmon.CpuTimes;
import com.jezhumble.javasysmon.JavaSysMon;

/**
 * @author bregier
 * 
 */
class CpuManagementSysmon implements CpuManagementInterface {
    public static long delay = 1000;

    JavaSysMon sysMon;

    CpuTimes cpuTimesOld;
    CpuTimes cpuTimesOldNext;
    long time;

    /**
     * 
     * @throws UnsupportedOperationException
     *             if System Load Average is not supported
     */
    public CpuManagementSysmon() throws UnsupportedOperationException {
        sysMon = new JavaSysMon();
        cpuTimesOld = sysMon.cpuTimes();
        cpuTimesOldNext = cpuTimesOld;
        time = System.currentTimeMillis();
    }

    /**
     * 
     * @return the load average
     */
    public double getLoadAverage() {
        long newTime = System.currentTimeMillis();
        CpuTimes cpuTimes = sysMon.cpuTimes();
        double rate = cpuTimes.getCpuUsage(cpuTimesOld);
        long delta = newTime - time;
        if ((delta) > delay) {
            if ((delta) > 10 * delay) {
                time = newTime;
                cpuTimesOldNext = cpuTimes;
                cpuTimesOld = cpuTimes;
            } else {
                time = newTime;
                cpuTimesOldNext = cpuTimes;
                cpuTimesOld = cpuTimesOldNext;
            }
        }
        return rate;
    }

}