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Groups > comp.lang.java.programmer > #21298

Re: Applet not running on the web

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On 2013-01-09 02:01 Lew wrote:
> emf wrote:
>> Arne Vajhøj wrote:
>>> emf wrote:
>>>> The webpage is:
>>>> httρs://files.nуu.edц/emf202/ρublic/jv/NatalTransits.html
>>>>
>>>> and you can find the code in
>>>>
>>>> httρs://files.nуu.edц/emf202/public/jv/transits/NatalTransitsApplet.java
>>>>
>>>> The applet was working without a problem from the beginning in the
>>>> eclipse applet viewer. Then I managed to make it work on browser from my
>>>> computer by putting the class and the csv files into a transits folder
>>>> (like the package in eclipse) and the html in the higher level
>>>> directory. Then I created the same structure in the webserver. The
> ...
>>> Ooops.
>>>
>>> #FileReader ephemeris = new FileReader("transits/ephemeris.csv");
>>>
>>> applets run client side!
>>>
>>> The user do not have a transits/ephemeris.csv file and the
>>> applet would not have priv to access it anyway.
>>>
>>> Stuff your class files *and* the CSV file in a jar
>>> file and let the Java code retrieve the CSV as a resource!
>>
>> Unfortunately the suggested solutions does not work. I have both
>
> What happens when you try it?
>
> What's the structure of the app inside the JAR?
>
> Where in the JAR did you put the CSV?
>
> How is the code attempting to retrieve the CSV?
>
> I sure hope you aren't calling 'new FileReader()' to get to it!
>
> Oh!
>
> 'FileReader ephemeris = new FileReader("transits/ephemeris.csv");'
>
> That's not how you read it. Use 'getResourceAsStream()' and put a
> 'StreamReader' around it.
>
> See the Javadocs for 'Class<T>'.
>
>> versions on the server:
>>
>> httρs://files.nуu.edц/emf202/public/jv/NatalTransitsA.html
>>
>> uses the jar archive, while
>>
>> httρs://files.nуu.edц/emf202/public/jv/NatalTransits.html
>>
>> uses the transits folder.
>>
>> Both work fine in my browser when running from the local files, but when
>
> Probably because the JAR version can still see the file system.
>
>> running through the Internet they both give a
>> java.security.AccessControlException, after using
>
> Probably because you still haven't changed the code to comply with
> Arne's suggestion.
>
> Additional comments:
>
> - Don't use TAB characters to indent code for public consumption.
> - For Christ's sake, man, Javadoc your code!

I haven't yet started using the Javadoc eclipse feature. Coming soon.

> - 'String textLine = null;' Don't assign values you will never use.

This happens when during the program development the compiler complaints 
that a variable has not been initialized, so you initialize it. In later 
stages of the development you change the code so the initialization is 
superfluous - though it doesn't hurt. At still later stage you may 
realize that it is superfluous, and you remove it.

> - 'String textLine = null;' declared at too broad a scope.
> - 'catch (Exception e)' is far too broad. Catch the particular exceptions.

If I had used catch (Exception e) from the beginning instead of 
IOException, I would have known what was wrong a couple of days earlier. 
So, from bitter experience, I learned that it is wise to use Exception, 
until at a later stage, when everything is working OK, you may return 
and change it, as an icing on the cake.

> - 'String birthday$' Never use '$' in your variable names. Ever.
>    It's for system-generated stuff only.

That was from my good old QBasic days... And I thought it was such a 
great idea! Pity. Anyway, I replaced $ with S when necessary.

>    Follow the naming conventions in the Java Coding Conventions.
> - 'int[][] planetArray' Generally, variable names should not indicate their
>    implementation but their purpose.

Since I learned about it, I enjoy Refactoring class, method, and 
variable names. I will change it when I think of an appropriate one.

> - 'int[][] planetArray' not the best type. You're storing what are essentially
>    strings there, as 'int' values. You can invent your own type if 'String'
>    doesn't suffice.

Ok, I made it String array, and the code is actually simpler now.

> - 'planet1 = (planet1 - planet2 > 21540) ? ...' Magic numbers are bad.

360° * 60' = 21600'. From 29PI00 to 01AR00 it's 2°, not 358°. I added a 
comment.

> - 'package transits;' Good.

As I've said, with the jar I can have everything in the same folder, so 
if eclipse wants to use packages I do not mind.

The new program:

https://files.nyu.edu/emf202/public/jv/NatalTransits.html

and the code

https://files.nyu.edu/emf202/public/jv/NatalTransitsApplet.java

I am grateful that you took the time to correct my mistakes and help me 
effectively in improving my code.

Regards,

Eustace

-- 
Date Calculator with all-purpose JS code
https://files.nyu.edu/emf202/public/js/dateCalculator.html

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Thread

Applet not running on the web emf <emfril@gmail.com> - 2013-01-06 19:46 -0500
  Re: Applet not running on the web Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 19:56 -0500
    Re: Applet not running on the web emf <emfril@gmail.com> - 2013-01-09 01:21 -0500
  Re: Applet not running on the web Arne Vajhøj <arne@vajhoej.dk> - 2013-01-06 19:58 -0500
    Re: Applet not running on the web emf <emfril@gmail.com> - 2013-01-07 03:39 -0500
    Re: Applet not running on the web emf <emfril@gmail.com> - 2013-01-09 01:40 -0500
      Re: Applet not running on the web Lew <lewbloch@gmail.com> - 2013-01-08 23:01 -0800
        Re: Applet not running on the web emf <emfril@gmail.com> - 2013-01-10 07:08 -0500
      Re: Applet not running on the web Arne Vajhøj <arne@vajhoej.dk> - 2013-01-09 20:51 -0500
        Re: Applet not running on the web emf <emfril@gmail.com> - 2013-01-10 07:19 -0500
          Re: Applet not running on the web Arne Vajhøj <arne@vajhoej.dk> - 2013-01-10 07:20 -0500
  Re: Applet not running on the web Roedy Green <see_website@mindprod.com.invalid> - 2013-01-08 22:56 -0800
    Re: Applet not running on the web emf <emfril@gmail.com> - 2013-01-09 02:46 -0500
      Re: Applet not running on the web Roedy Green <see_website@mindprod.com.invalid> - 2013-01-09 11:22 -0800
    Re: Applet not running on the web Arne Vajhøj <arne@vajhoej.dk> - 2013-01-09 20:44 -0500
  Re: Applet not running on the web Roedy Green <see_website@mindprod.com.invalid> - 2013-01-09 11:26 -0800

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