/**
* Iterates through the provided list and classifies the mobility mode for each list item.
*
* @param sensorDataPoints the data points to classify
* @return a list of ClassifiedPoints. The list will be in the same order as the provided list.
* @throws IllegalArgumentException if the provided list is null
*/
public static List<ClassifiedPoint> classify(List<SensorDataPoint> sensorDataPoints) {
if (sensorDataPoints == null) {
throw new IllegalArgumentException("sensorDataPoints is required");
}
if (sensorDataPoints.contains(null)) {
throw new IllegalArgumentException("sensorDataPoints contains null");
}
List<ClassifiedPoint> classifiedPoints = new ArrayList<ClassifiedPoint>();
// This could be an instance variable because it is stateless
MobilityClassifier mobilityClassifier = new MobilityClassifier();
WifiScan previousWifiScan = null;
String previousMode = null;
for (SensorDataPoint sensorDataPoint : sensorDataPoints) {
Classification classification =
mobilityClassifier.classify(
sensorDataPoint.getAccelerometerSamples(),
sensorDataPoint.getSpeed(),
sensorDataPoint.getWifiScan(),
previousWifiScan,
previousMode);
previousWifiScan = sensorDataPoint.getWifiScan();
previousMode = classification.getMode();
classifiedPoints.add(new ClassifiedPoint(sensorDataPoint.getId(), classification));
}
return classifiedPoints;
}
/**
* Runs the classifier against all of the Mobility points in the list.
*
* @param mobilityPoints The Mobility points that are to be classified by the server.
* @throws ServiceException Thrown if there is an error with the classification service.
*/
public void classifyData(final String uploadersUsername, final List<MobilityPoint> mobilityPoints)
throws ServiceException {
// If the list is empty, just exit.
if (mobilityPoints == null) {
return;
}
// Create a new classifier.
MobilityClassifier classifier = new MobilityClassifier();
// Create place holders for the previous data.
String previousWifiMode = null;
List<WifiScan> previousWifiScans = new LinkedList<WifiScan>();
// This is a bit more involved now that we are doing everything through
// the observers.
/*
if(mobilityPoints.size() > 0) {
try {
MobilityPoint firstPoint = mobilityPoints.get(0);
DateTime startDate = new DateTime();
startDate =
new DateTime(
firstPoint.getTime() -
MAX_MILLIS_OF_PREVIOUS_WIFI_DATA);
List<MobilityPoint> previousPoints =
userMobilityQueries.getMobilityInformation(
uploadersUsername,
startDate,
new DateTime(firstPoint.getTime()),
null,
null,
null);
for(MobilityPoint previousPoint : previousPoints) {
try {
previousWifiScans.add(previousPoint.getWifiScan());
}
catch(DomainException e) {
// This point does not have a WifiScan, so we will skip
// it.
}
}
}
catch(DataAccessException e) {
throw new ServiceException(e);
}
}
*/
// For each of the Mobility points,
for (MobilityPoint mobilityPoint : mobilityPoints) {
// If the data point is of type error, don't attempt to classify
// it.
if (mobilityPoint.getMode().equals(Mode.ERROR)) {
continue;
}
// If the SubType is sensor data,
if (MobilityPoint.SubType.SENSOR_DATA.equals(mobilityPoint.getSubType())) {
SensorData currSensorData = mobilityPoint.getSensorData();
// Get the Samples from this new point.
List<Sample> samples;
try {
samples = mobilityPoint.getSamples();
} catch (DomainException e) {
throw new ServiceException("There was a problem retrieving the samples.", e);
}
// Get the new WifiScan from this new point.
WifiScan wifiScan;
if (mobilityPoint.getSensorData().getWifiData() == null) {
wifiScan = null;
} else {
try {
wifiScan = mobilityPoint.getWifiScan();
} catch (DomainException e) {
throw new ServiceException("The Mobility point does not contain WiFi data.", e);
}
}
// Prune out the old WifiScans that are more than 10 minutes
// old.
long minPreviousTime = mobilityPoint.getTime() - MAX_MILLIS_OF_PREVIOUS_WIFI_DATA;
Iterator<WifiScan> previousWifiScansIter = previousWifiScans.iterator();
while (previousWifiScansIter.hasNext()) {
if (previousWifiScansIter.next().getTime() < minPreviousTime) {
previousWifiScansIter.remove();
} else {
// Given the fact that the list is ordered, we can now
// be assured that all of the remaining WiFi scans are
// invalid.
break;
}
}
// Classify the data.
Classification classification =
classifier.classify(
samples, currSensorData.getSpeed(), wifiScan, previousWifiScans, previousWifiMode);
// Update the place holders for the previous data.
if (wifiScan != null) {
previousWifiScans.add(wifiScan);
}
previousWifiMode = classification.getWifiMode();
// If the classification generated some results, pull them out
// and store them in the Mobility point.
if (classification.hasFeatures()) {
try {
mobilityPoint.setClassifierData(
classification.getFft(),
classification.getVariance(),
classification.getAverage(),
MobilityPoint.Mode.valueOf(classification.getMode().toUpperCase()));
} catch (DomainException e) {
throw new ServiceException(
"There was a problem reading the classification's information.", e);
}
}
// If the features don't exist, then create the classifier data
// with only the mode.
else {
try {
mobilityPoint.setClassifierModeOnly(
MobilityPoint.Mode.valueOf(classification.getMode().toUpperCase()));
} catch (DomainException e) {
throw new ServiceException("There was a problem reading the classification's mode.", e);
}
}
}
}
}
