refactoring sample

test1.java

if (date.before(SUMMER_START) || date.after(SUMMER_END))
    charge = quantity * _winterRate + _winterServiceCharge;
else charge = quantity * _summerRate;


if (notSummer(date))
    charge = winterCharge(quantity);
else charge = summerCharge(quantity);

private boolean notSummer(Date date) {
    return date.before(SUMMER_START) || date.after(SUMMER_END);
}
private double summerCharge(int quantity)
{
    return quantity * _summerRate;
}
private double winterCharge(int quantity)
{
    return quantity * _winterRate + _winterServiceCharge;
}