/*
* Copyright (c) 2005-2010 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 .
*
*/
package de.tud.kom.p2psim.impl.vehicular.caching.decision;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import de.tudarmstadt.maki.simonstrator.api.Time;
import de.tudarmstadt.maki.simonstrator.api.component.sensor.environment.data.RoadProperty;
import de.tudarmstadt.maki.simonstrator.api.component.sensor.environment.data.VectoralProperty;
import de.tudarmstadt.maki.simonstrator.api.component.sensor.environment.data.jam.VectoralJamProperty;
import de.tudarmstadt.maki.simonstrator.api.component.vehicular.caching.decision.CacheDecisionStrategy;
import de.tudarmstadt.maki.simonstrator.api.component.vehicular.information.AvailableInformationAttributes;
import de.tudarmstadt.maki.simonstrator.api.component.vehicular.information.PointInformation;
import de.tudarmstadt.maki.simonstrator.api.component.vehicular.information.RoadInformation;
public class TTLbasedCacheDecisionStrategy implements CacheDecisionStrategy {
private static final long SCALING = Time.SECOND;
private static final double ACCURACY_FACTOR = 100000;
private long ttl = 300 * Time.SECOND / SCALING;
private double accuracy = 1;
private double costWrongKeep = 1;
private double costWrongChange = 1;
private Object _lastDecision = false;
public TTLbasedCacheDecisionStrategy(Map pParams) {
for (Entry param : pParams.entrySet()) {
switch (param.getKey()) {
case "ACCURACY":
accuracy = Double.valueOf(param.getValue());
break;
case "COST_RATIO":
double ratio = Double.valueOf(param.getValue());
costWrongChange = 2 / (ratio + 1);
costWrongKeep = 2 - costWrongChange;
break;
default:
break;
}
}
}
public double getCostWrongChange() {
return costWrongChange;
}
public double getCostWrongKeep() {
return costWrongKeep;
}
@Override
public T decideOnCorrectInformation(
List pSimilarPointInformation) {
if (pSimilarPointInformation.size() == 1) {
T decision = pSimilarPointInformation.get(0);
_lastDecision = decision.getValue();
return decision;
} else if (pSimilarPointInformation.size() == 0) {
return null;
}
Collections.sort(pSimilarPointInformation, new Comparator() {
@Override
public int compare(T pArg0, T pArg1) {
return Long.compare(pArg0.getDetectionDate(), pArg1.getDetectionDate());
}
});
long minTimestamp = Long.MAX_VALUE;
long maxTimestamp = 0;
Object value = pSimilarPointInformation.get(0).getValue();
boolean differentValue = false;
for (T t : pSimilarPointInformation) {
if (!t.hasAttribute(AvailableInformationAttributes.TTL)) {
throw new AssertionError("Unable to perform TTL-based majority voting witout TTL");
}
long timestamp = t.getDetectionDate();
if (timestamp < minTimestamp) {
minTimestamp = timestamp;
}
if (timestamp > maxTimestamp) {
maxTimestamp = timestamp;
}
if (!value.equals(t.getValue())) {
differentValue = true;
}
}
if (differentValue) {
long difference = maxTimestamp - minTimestamp;
if (difference == 0) {
return pSimilarPointInformation.get(pSimilarPointInformation.size() - 1);
}
double rate = difference / ((double) (pSimilarPointInformation.size() - 1) * SCALING);
long ttl = (long)pSimilarPointInformation.get(0).getAttribute(AvailableInformationAttributes.TTL) / SCALING;
rate = Math.min(rate, ttl / 10.0);
double b;
if (Boolean.FALSE.equals(_lastDecision)) {
b = determineB(rate, 1 - accuracy, ttl, costWrongKeep, costWrongChange);
} else {
b = determineB(rate, 1 - accuracy, ttl, costWrongChange, costWrongKeep);
}
Map