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Newsgroups: comp.lang.java.programmer
Date: Wed, 17 Apr 2019 06:42:41 -0700 (PDT)
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Subject: Re: Java variable access
From: Eric Douglas <e.d.programmer@gmail.com>
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Xref: csiph.com comp.lang.java.programmer:38923

On Tuesday, April 16, 2019 at 4:46:33 PM UTC-4, Eric Sosman wrote:
>      What is wrong (tm) with
> 
> 	public void setUnitPrice(double unitPrice) {
> 	    if (unitPrice <= 0 || !Double.isFinite(unitPrice)) {
> 	        throw new IllegalArgumentException(
> 	            "bad price: " + unitPrice);
> 	    }
> 	    if (unitPrice != this.unitPrice) {
> 	        this.unitPrice = unitPrice;
> 	        fireChangeEvent(this, PRICE_CHANGED);
> 	    }
> 	}
> 

If you leave off the validation and just declare class variable public double unitPrice, you either validate it where it gets used or never validate assuming it's ok to just throw an error where it would be used if it somehow gets an invalid value.

If you would have a number of variables that you want the same exact validation you could build in a private method:
public void setUnitPrice(double unitPrice) {
  setPositiveValue(values.UNITPRICE,unitPrice);
}
(where UNITPRICE is an enum) ?

or you could just use generated code, with a UI (IDE) or Eclipse plugin type thing.
We do use several languages at my company and one of them we did write our own custom IDE (in C#) which inserts certain common code blocks which have to be in every program but would be tedious to write.