/**
* Calculates the fuel economy (based on the user's preferences) since the previous fill-up.
*
* @return the fuel economy since the previous fill-up.
*/
public double calcEconomy() {
if (m_partial) {
return -1D;
}
if (m_economy == 0D) {
FillUp previous = getPrevious();
if (previous == null) {
return -1D;
}
double distance = calcDistance();
double fuel = getAmount();
while (previous != null) {
if (previous.isPartial() == false) {
break;
}
// partial; we need to keep iterating
distance += previous.calcDistance();
fuel += previous.getAmount();
previous = previous.getPrevious();
}
m_economy = m_calculator.calculateEconomy(distance, fuel);
}
return m_economy;
}
