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package se.leap.bitmaskclient.eip;
import static se.leap.bitmaskclient.base.utils.TimezoneHelper.timezoneDistance;
import static se.leap.bitmaskclient.base.utils.TimezoneHelper.getCurrentTimezone;
import android.util.Log;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
public class GatewaySelector {
private final static String TAG = GatewaySelector.class.getSimpleName();
List<Gateway> gateways;
TreeMap<Integer, Set<Gateway>> offsets;
public GatewaySelector(List<Gateway> gateways) {
this.gateways = gateways;
this.offsets = calculateOffsets();
}
public ArrayList<Gateway> getGatewaysSortedByDistance() {
ArrayList<Gateway> list = new ArrayList<>();
int i = 0;
for (Collection<Gateway> gatewayCollection : offsets.values()) {
list.addAll(gatewayCollection);
}
return list;
}
public Gateway select() {
return closestGateway();
}
public Gateway select(int nClosest) {
int i = 0;
for (Map.Entry<Integer,Set<Gateway>> entrySet : offsets.entrySet()) {
for (Gateway gateway : entrySet.getValue()) {
if (i == nClosest) {
return gateway;
}
i = i + 1;
}
}
Log.e(TAG, "There are less than " + (nClosest + 1) + " Gateways available.");
return null;
}
private Gateway closestGateway() {
return offsets.isEmpty() ? null : offsets.firstEntry().getValue().iterator().next();
}
// calculateOffsets randomizes the order of Gateways with the same distance, e.g. from the same location
private TreeMap<Integer, Set<Gateway>> calculateOffsets() {
TreeMap<Integer, Set<Gateway>> offsets = new TreeMap<Integer, Set<Gateway>>();
int localOffset = getCurrentTimezone();
for (Gateway gateway : gateways) {
int dist = timezoneDistance(localOffset, gateway.getTimezone());
Set<Gateway> set = (offsets.get(dist) != null) ?
offsets.get(dist) : new HashSet<Gateway>();
set.add(gateway);
offsets.put(dist, set);
}
return offsets;
}
}
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