de.tud.kom.p2psim.impl.network.modular.st.ploss.PingErPacketLoss.java Source code

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Here is the source code for de.tud.kom.p2psim.impl.network.modular.st.ploss.PingErPacketLoss.java

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/*
 * Copyright (c) 2005-2011 KOM - Multimedia Communications Lab
 *
 * This file is part of PeerfactSim.KOM.
 * 
 * PeerfactSim.KOM 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
 * any later version.
 * 
 * PeerfactSim.KOM 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 PeerfactSim.KOM.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package de.tud.kom.p2psim.impl.network.modular.st.ploss;

import org.apache.commons.math.random.RandomGenerator;
import org.apache.log4j.Logger;

import de.tud.kom.p2psim.impl.network.modular.ModularNetLayer;
import de.tud.kom.p2psim.impl.network.modular.ModularNetMessage;
import de.tud.kom.p2psim.impl.network.modular.db.NetMeasurementDB;
import de.tud.kom.p2psim.impl.network.modular.db.NetMeasurementDB.SummaryRelation;
import de.tud.kom.p2psim.impl.network.modular.st.PLossStrategy;
import de.tud.kom.p2psim.impl.simengine.Simulator;
import de.tud.kom.p2psim.impl.util.logging.SimLogger;

/**
 * Applies a packet loss as measured by the PingEr project
 * 
 * @author Leo Nobach <peerfact@kom.tu-darmstadt.de>
 * 
 * @version 05/06/2011
 */
public class PingErPacketLoss implements PLossStrategy {

    RandomGenerator rand = Simulator.getRandom();

    static Logger log = SimLogger.getLogger(PingErPacketLoss.class);

    @Override
    public boolean shallDrop(ModularNetMessage msg, ModularNetLayer nlSender, ModularNetLayer nlReceiver,
            NetMeasurementDB db) {

        if (db == null)
            throw new IllegalArgumentException("The PingER packet loss strategy can not access any network "
                    + "measurement database. You may not have loaded it in the config file.");

        SummaryRelation sumRel = db.getMostAccurateSummaryRelation(nlSender.getDBHostMeta(),
                nlReceiver.getDBHostMeta());

        if (sumRel == null)
            throw new AssertionError("No summary relation could be found for " + nlSender + " - " + nlReceiver);

        // If the message consists of multiple fragments, the loss probability
        // will be the probability that all fragments have arrived, and
        // every fragment itself has the probability of "sumRel.getpLoss()" to
        // be dropped
        double prob = 1d - Math.pow(1d - sumRel.getpLoss() * 0.01, msg.getNoOfFragments());
        log.debug("Dropping with probability " + prob + ", fragments " + msg.getNoOfFragments());
        return rand.nextDouble() < prob;
    }

    @Override
    public void writeBackToXML(BackWriter bw) {
        // No simple/complex types to write back
    }

}