How can I change a value in a set method depending on a boolean's answer in Java?

I’m trying to change the VAT rate of an item depending if it’s a luxury item or not.

I’ve tried using an if inside of my set method but it only uses the pre-set value that I gave it.

private double vat = 0.08;

is my preset value. My get and set methods are:

public double getVat() {
    return this.vat;
}

public void setVat(double vat) {
    if(lux=true) {
    this.vat = 0.10;
    }
    
    else if(lux=false) {
    this.vat = vat;
    }
}

and the variable lux is

private boolean lux;

Also, this is what my constructor looks like:

public ProductTest(String pname, double price, boolean lux) {
    this.pname = pname;
    
    if(price>0) {
    this.price = price;
    }
    else {
    this.price = 0;
    }
    
    this.lux = lux; //If product type is luxury , =true ----- if product type is not luxury, =false
    
}

When I create and object and mark the lux variable as true or false, VAT takes the value of 0.08.

ProductTest p = new ProductTest("apple", 10, true);
System.out.println(p.getVat());

Output: 0.08

ProductTest p = new ProductTest("apple", 10, false);
System.out.println(p.getVat());

Output: 0.08

What can I do to overcome this? Thanks.

>Solution :

You nede to call setVat in the constructor to apply the logic

public ProductTest(String pname, double price, boolean lux) {
    this.pname = pname;
    this.price = Math.max(0, price);
    this.lux = lux;
    setVat(vat);
}

public void setVat(double vat) {
    if (lux) {
        this.vat = 0.10;
    } else {
        this.vat = vat;
    }
}

Could even be shorter with ternary operator

public void setVat(double vat) {
    this.vat = lux ? 0.10 : vat;
}

Or do it differently by putting the logic in the getVat

public ProductTest(String pname, double price, boolean lux) {
    this.pname = pname;
    this.price = Math.max(0, price);
    this.lux = lux;
}

public double getVat() {
    return lux ? 0.10 : vat;
}

public void setVat(double vat) {
    this.vat = vat;
}