object.attribute vs. object.getAttribute()

Aurelio Martin Massoni amartin at traza-si.com
Tue Sep 16 13:22:35 CEST 2003


Read this nice article "Why getter and setter methods are evil: Make
your code more maintainable by avoiding accessors"

http://www.javaworld.com/javaworld/jw-09-2003/jw-0905-toolbox.html



"Roy Smith" <roy at panix.com> escribió en el mensaje
news:roy-81B3E5.20291015092003 at reader2.panix.com...
> For the past 6-8 months, I've spent most of my time writing C++ and a
> little bit of Java.  Both of these languages support and encourage the
> use of private data and explicit accessor functions, i.e. instead of
> writing x = foo.bar, you write x = foo.getBar().  Now that I'm back to
> writing Python, I find myself in a quandry.
>
> Historically, I've always avoided accessor functions and just reached
> directly into objects to get the value of their attributes.  Since
> Python doesn't have private data, there really isn't much advantage to
> writing accessors, but somehow I'm now finding that it just feels
wrong
> not to.  I'm not sure if this feeling is just a C++/Java-ism that will
> cure itself with time, or if perhaps it really does make sense and I
> should change the way I code.
>
> On the plus side, accessors/mutators give me:
>
> 1) Implicit documentation of which attributes I intended to be part of
> an object's externally visible state (accessors).
> 2) Hooks to do data checking or invarient assertions (mutators).
> 3) Decoupling classes by hiding the details of data structures.
> 4) Vague feeling that I'm doing a good thing by being more in line
with
> mainstream OO practices :-)
>
> On the minus side:
>
> 1) More typing (which implies more reading, which I think reduces the
> readability of the finished product).
> 2) Need to write (and test) all those silly little functions.
> 3) Performance hit due to function call overhead.
> 4) Only the appearance of private data (modulo some slots hackery).
> 5) Code is harder to change (adding functionality means going back and
> adding more slots).
> 6) Vague feeling that I'm dirtying myself by letting C++ and Java
change
> my Python coding habits :-)
>
> Comments?






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