Why is "Set()" function better than modifying public variable?

Question

This one is bothering me for a while now :)

Suppose we have a variable - why is writing a Set function better practice than simply modifying variable's data (and setting the variable to be public instead of private)?

It's less coding that way and I can't see any "security" issues.

Because one day you want to add something, like a simple null check, and you have 1001 methods breaking up when trying to pass that public variable to a setter. — devoured elysium, Feb 26 '12 at 22:53
Yes, it does. In Python, for example, many of the arguments in favour of using getters/setters don't apply, and so they're relatively rare. — DSM, Feb 26 '12 at 22:58
possible duplicate of [Why use getters and setters?](http://stackoverflow.com/questions/1568091/why-use-getters-and-setters) — DNA, Feb 26 '12 at 22:59
Because I have an anroid Runnable and I was wondering why doing Set() instead of public variable. — c0dehunter, Feb 27 '12 at 07:47

eouw0o83hf · Accepted Answer · 2012-02-27T13:26:33.647

7

Sometimes when setting a variable, you may want to do something else with the given value other than instantly place it in the class's variable: for instance, you may want to validate it or update another value that is related.

Basically, it lets the class which owns that variable control what can be done to it, and the specific series of events that occur when it is altered.

edited Feb 27 '12 at 13:26

answered Feb 26 '12 at 22:56

eouw0o83hf

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score 2 · Answer 2 · answered Feb 26 '12 at 23:18

It also needs to be mentioned that it is not always better to use "set" methods. Blind compliance with patterns may lead to overcomplicated code. If class acts as just simple (really simple) data container, then public access is often acceptable. In example, look at java.awt.Rectangle or at java.awt.Point classes.

score 0 · Answer 3 · answered Feb 26 '12 at 22:58

It all has to do with object orientation and how strict you are in that doctrine. If you strictly follow all the guidelines, it is bad to directly use methods and identifiers from one class, by the other. Technically there is no objection.

This discussion is the same as the static - no static discussion. The (self proclaimed) guru, found that sacrilege, but you put your computer no obstacle in the way, if you put your whole program is static.

Why is "Set()" function better than modifying public variable?

3 Answers3