Java-调用方法时加在一起

Question

this might seem daft but I just can't seem to figure this out. Ok so I'm new to programming and I've hit a snag when it comes to doubling an amount by itself.

I'm calling a method from another object class which gives the total price of wine selected from a customer.

ie - winecase.getPrice();

Within the class website (the class im calling the external method from) theres a field called salesTotal which adds the amount of revenue generated from the website. The above method is being called from within the checkout method of the website class (if that makes sense).

I basically want the field to store the value of the getPrice each time the checkout method is called... for example if the case of wine was £30, I want it to be £30 when the method is first called but then £60 the second time £90 the next etc (so effectively doubling itself).

Any help would be greatly appreciated.

Answer 1

You could try using a setter, ie

 BigDecimal salesTotal;

 public BigDecimal getSalesTotal() {
      return salesTotal;
 }

 public void setSalesTotal(BigDecimal salesTotal) {
      this.salesTotal = salesTotal;
 }

and then call

setSalesTotal(this.getSalesTotal() + winecase.getPrice());

or encapsulate this logic in a separate method which will receive an amount of money that has to be added to total as a parameter like this:

calculateSalesTotal(BigDecimal amountToAdd) {
    this.setSalesTotal(this.getSalesTotal() + amountToAdd);
}

and then call it calculateSalesTotal(winecase.getPrice());