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Re: How do you update the view space of a JTable?

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On 10/31/2017 9:13 AM, Eric Douglas wrote:
> On Tuesday, October 31, 2017 at 8:33:09 AM UTC-4, Eric Sosman wrote:
>>>
>>> https://pastebin.com/zrUESqc4
>>
>>       Ah, yes, how silly of me: I should have looked in a completely
>> different thread to find your link.  Pray accept my apologies for
>> being so lax.
>>
> 
> That is what I said, check the other thread, so far no one responded there.  I can move that conversation here if it'll help.

     A brief look at the code reveals one serious error (of the
kind you'll "usually" get away with), one serious error that no
Java programmer should ever commit, a few venial sins, and some
opportunities for stylistic improvement.  What it doesn't reveal
is the code's purpose nor how it fails to fulfill that purpose,
which makes it a little hard to diagnose ...

     Herewith, the problems apparent to my brief inspection:

     - Serious: Swing is not thread-safe, and almost all
Swingstuff must be done on the event dispatching thread (EDT).
Your code constructs and launches a JFrame and all its contents from
whatever thread executes main().  You'll "usually" get away with this,
because Murphy waits until the Big Demo for the Big Boss.  See
https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html

     - Serious: `catch (Exception e)'?  Are you KIDDING?

     - Venial: Various constructors call potentially overridable
methods, which could be a problem if any of your classes are someday
extended.  You could cure this by making the involved classes final,
or by making the methods final, or (since you probably don't need to
override some of them) by explicitly calling the superclass' method,
as in `super.getContentPane()' instead of just `getContentPane()'.
Or, you could just hope no one will ever extend the class and find
some reason to override setAutoResizeMode() or whatever.

     - Venial: Various constructors leak the `this' reference before
`this' is fully constructed.  The transgression would ordinarily be
worse than venial, but adding event listeners "should probably be"
safe since they're unlikely to be called until a good deal later.
IMHO this is an infelicity in the architecture of Swing/AWT: You
would *like* a constructor to deliver a fully-functional ready-to-
rumble instance of a JFrame or whatever, but if you're really not
supposed to register event listeners in a constructor ...  The
squeaky-clean approach, I guess, is to have a post-construction
init() method, which strikes me as Ugly.  Or ignore it and hope.

     - Venial: The `MyTable' class is package-private, yet some
`public' methods either return it or use it as a parameter.  Either
make the class `public' or make the methods package-private: Pay
attention to your access levels.

     - Style: Sleekness could be improved with a lambda expression
instead of an anonymous inner subclass of AdjustmentListener.

     - Style: Use `intValue' instead of `new Integer(intValue)' and
let auto-boxing take care of wrapping it.  (May produce a tiny gain
in efficiency, too.)

     - Style: Instead of calling System.exit() on a window-close event,
you could just `setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)'.

     - Style: The types of some fields are unnecessarily specific:
`AbstractTableModel' instead of `TableModel', that sort of thing.
It is usually "better form" to use the least specific declaration
that's suitable -- often, an interface rather than a particular
implementation of that interface.  That way, you retain flexibility
to change the implementation later with little or no upheaval.

     I sincerely doubt that fixing any of the above will help you
in the least with whatever problem you're having in the pursuit of
whatever goal you're after, but "Cleanliness is next to Godliness,
also next to impossible."

-- 
esosman@comcast-dot-net.invalid
Eleven hundred seventy-seven days to go.

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Thread

How do you update the view space of a JTable? Eric Douglas <e.d.programmer@gmail.com> - 2017-10-17 08:47 -0700
  Re: How do you update the view space of a JTable? Eric Douglas <e.d.programmer@gmail.com> - 2017-10-18 06:11 -0700
  Re: How do you update the view space of a JTable? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-10-30 17:41 +0100
    Re: How do you update the view space of a JTable? Eric Douglas <e.d.programmer@gmail.com> - 2017-10-30 10:29 -0700
      Re: How do you update the view space of a JTable? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-10-31 11:10 +0100
        Re: How do you update the view space of a JTable? Eric Douglas <e.d.programmer@gmail.com> - 2017-10-31 04:46 -0700
          Re: How do you update the view space of a JTable? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-10-31 07:59 -0400
            Re: How do you update the view space of a JTable? Eric Douglas <e.d.programmer@gmail.com> - 2017-10-31 05:21 -0700
              Re: How do you update the view space of a JTable? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-10-31 08:32 -0400
                Re: How do you update the view space of a JTable? Eric Douglas <e.d.programmer@gmail.com> - 2017-10-31 06:13 -0700
                Re: How do you update the view space of a JTable? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-10-31 17:13 -0400
                Re: How do you update the view space of a JTable? Daniele Futtorovic <da.futt.news@laposte.net> - 2017-10-31 23:33 +0100
                Re: How do you update the view space of a JTable? Eric Douglas <e.d.programmer@gmail.com> - 2017-11-01 06:29 -0700
                Re: How do you update the view space of a JTable? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-11-01 10:37 -0400
                Re: How do you update the view space of a JTable? Eric Douglas <e.d.programmer@gmail.com> - 2017-11-01 08:37 -0700
                Re: How do you update the view space of a JTable? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-11-01 13:20 -0400

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