Command line parameter checking?

[Volker Held]

Hi,

does anybody has a "good" example for
command line parameter checking?

I write a lot of command line tools for
java, recently they have become more
complex and it´s required to check a
number of command line switches in order
to provide successfull execution of the
program.

Now the checking in general is no
problem, but i´m uneasy about which
design approach to use...

Until now i usually used an launcher
class that passes the command line args
to a "validating" module ( class ) that
also sets the class fields if the args
were correct.
I used to set the class fields in the
constructor of the "validating" class
and a lot more... that is i do a lot of
preparation/work in the constructor...
now i ask myself is that really a good
way to go or are there better/more
efficient ways...

Thanks for any advice

Volker

[Per]

Maybe it would be an idea to use xml. You could make an xml file with the
setup condition and then use an xml parser like the one from ibm (free).
Some of the validating could then be performed with the xml's dtd (this validating
is automatic performed by the ibm parser).

If you make use of xml to hold the setup values it can esaly be changed if
you need other values to your application and you will have a great overview
of the data.
If you have not worked with xml and dtd it will take some time to understand
it, but xml and java is working very good together and you will be able to
find a lot of java software on the net that can performe the parsing.

To take a quick look at xml see
http://www.w3schools.com/
There is no java parser on this link.


regards
Per
Volker Held <vheld@gwdg.de> wrote:
>Hi,
>
>does anybody has a "good" example for
>command line parameter checking?
>
>I write a lot of command line tools for
>java, recently they have become more
>complex and it´s required to check a
>number of command line switches in order
>to provide successfull execution of the
>program.
>
>Now the checking in general is no
>problem, but i´m uneasy about which
>design approach to use...
>
>Until now i usually used an launcher
>class that passes the command line args
>to a "validating" module ( class ) that
>also sets the class fields if the args
>were correct.
>I used to set the class fields in the
>constructor of the "validating" class
>and a lot more... that is i do a lot of
>preparation/work in the constructor...
>now i ask myself is that really a good
>way to go or are there better/more
>efficient ways...
>
>Thanks for any advice
>
>Volker
>

[Volker Held]

Hello again Per,

XML is a great idea, haven´t thought of
using it for configuration files yet,
despite the fact that i´m familiar with
parsing XML.

But the main problem is that ( i try to
cut it short ) i have to program an
application that will port XML sources
into a relational DB ( MySQL ) and it
has been specified as a command-line tool.
Even if i write the URL to the DB into
an XML config file, i still have the
problem with authorisation.
Use of the program will be restriced to
a few people ( who in detail is yet
unknown and shall be coded flexible ).
Maybe i´m wrong, but in this case i
think the best way to provide different
user access is to get the username and
password by using the command line
params ( String[] args ) - and i´m
looking for an effective way to check
those...

Per wrote:
> Maybe it would be an idea to use xml. You could make an xml file with the
> setup condition and then use an xml parser like the one from ibm (free).
> Some of the validating could then be performed with the xml's dtd (this validating
> is automatic performed by the ibm parser).
>
> If you make use of xml to hold the setup values it can esaly be changed if
> you need other values to your application and you will have a great overview
> of the data.
> If you have not worked with xml and dtd it will take some time to understand
> it, but xml and java is working very good together and you will be able to
> find a lot of java software on the net that can performe the parsing.
>
> To take a quick look at xml see
> http://www.w3schools.com/
> There is no java parser on this link.
>
>
> regards
> Per
> Volker Held <vheld@gwdg.de> wrote:
>
>>Hi,
>>
>>does anybody has a "good" example for
>>command line parameter checking?
>>
>>I write a lot of command line tools for
>>java, recently they have become more
>>complex and it´s required to check a
>>number of command line switches in order
>>to provide successfull execution of the
>>program.
>>
>>Now the checking in general is no
>>problem, but i´m uneasy about which
>>design approach to use...
>>
>>Until now i usually used an launcher
>>class that passes the command line args
>>to a "validating" module ( class ) that
>>also sets the class fields if the args
>>were correct.
>>I used to set the class fields in the
>>constructor of the "validating" class
>>and a lot more... that is i do a lot of
>>preparation/work in the constructor...
>>now i ask myself is that really a good
>>way to go or are there better/more
>>efficient ways...
>>
>>Thanks for any advice
>>
>>Volker
>>
>
>

[Per]

Hi again
Ohh sorry I misunderstood you.
Hmmm, I have no experience with that myself.
But if you take the input (username, password....) via the command line,
then as I see it you will create an instance of the class each time a user
is tryig to connect. And if a user is trying to connect with an illigal password
he/she will course manuy objects to be created. I know that the garbage collector
will eliminate them, but still.
And if one is using an illigal password then as I see it you will not be
able to count the number of tryings this could be a problem if a hacker is
trying to get access.
I do not no if any of this could be a problem for you and as I said I do
not have any experience with this my self so I can be of no help - sorry

Good luck
Per


Volker Held <vheld@gwdg.de> wrote:
>Hello again Per,
>
>XML is a great idea, haven´t thought of
>using it for configuration files yet,
>despite the fact that i´m familiar with
>parsing XML.
>
>But the main problem is that ( i try to
>cut it short ) i have to program an
>application that will port XML sources
>into a relational DB ( MySQL ) and it
>has been specified as a command-line tool.
>Even if i write the URL to the DB into
>an XML config file, i still have the
>problem with authorisation.
>Use of the program will be restriced to
>a few people ( who in detail is yet
>unknown and shall be coded flexible ).
>Maybe i´m wrong, but in this case i
>think the best way to provide different
>user access is to get the username and
>password by using the command line
>params ( String[] args ) - and i´m
>looking for an effective way to check
>those...
>
>Per wrote:
>> Maybe it would be an idea to use xml. You could make an xml file with
the
>> setup condition and then use an xml parser like the one from ibm (free).
>> Some of the validating could then be performed with the xml's dtd (this
validating
>> is automatic performed by the ibm parser).
>>
>> If you make use of xml to hold the setup values it can esaly be changed
if
>> you need other values to your application and you will have a great overview
>> of the data.
>> If you have not worked with xml and dtd it will take some time to understand
>> it, but xml and java is working very good together and you will be able
to
>> find a lot of java software on the net that can performe the parsing.
>>
>> To take a quick look at xml see
>> http://www.w3schools.com/
>> There is no java parser on this link.
>>
>>
>> regards
>> Per
>> Volker Held <vheld@gwdg.de> wrote:
>>
>>>Hi,
>>>
>>>does anybody has a "good" example for
>>>command line parameter checking?
>>>
>>>I write a lot of command line tools for
>>>java, recently they have become more
>>>complex and it´s required to check a
>>>number of command line switches in order
>>>to provide successfull execution of the
>>>program.
>>>
>>>Now the checking in general is no
>>>problem, but i´m uneasy about which
>>>design approach to use...
>>>
>>>Until now i usually used an launcher
>>>class that passes the command line args
>>>to a "validating" module ( class ) that
>>>also sets the class fields if the args
>>>were correct.
>>>I used to set the class fields in the
>>>constructor of the "validating" class
>>>and a lot more... that is i do a lot of
>>>preparation/work in the constructor...
>>>now i ask myself is that really a good
>>>way to go or are there better/more
>>>efficient ways...
>>>
>>>Thanks for any advice
>>>
>>>Volker
>>>
>>
>>
>

[Volker Held]

Jeez Per,

you just screwed my day!
Haven´t though of a possible DOS/Brute
attack... though it won´t be a problem
with this application - the next i´m
going to write is a GUI client
software... thanks for that reminder.

And thanks... you might haven´t been
able to solve my command line problem,
but XML config files and the reminder of
security issues were great help.

cheers

Volker

Per wrote:
> Hi again
> Ohh sorry I misunderstood you.
> Hmmm, I have no experience with that myself.
> But if you take the input (username, password....) via the command line,
> then as I see it you will create an instance of the class each time a user
> is tryig to connect. And if a user is trying to connect with an illigal password
> he/she will course manuy objects to be created. I know that the garbage collector
> will eliminate them, but still.
> And if one is using an illigal password then as I see it you will not be
> able to count the number of tryings this could be a problem if a hacker is
> trying to get access.
> I do not no if any of this could be a problem for you and as I said I do
> not have any experience with this my self so I can be of no help - sorry
>
> Good luck
> Per
>
>
> Volker Held <vheld@gwdg.de> wrote:
>
>>Hello again Per,
>>
>>XML is a great idea, haven´t thought of
>>using it for configuration files yet,
>>despite the fact that i´m familiar with
>>parsing XML.
>>
>>But the main problem is that ( i try to
>>cut it short ) i have to program an
>>application that will port XML sources
>>into a relational DB ( MySQL ) and it
>>has been specified as a command-line tool.
>>Even if i write the URL to the DB into
>>an XML config file, i still have the
>>problem with authorisation.
>>Use of the program will be restriced to
>>a few people ( who in detail is yet
>>unknown and shall be coded flexible ).
>>Maybe i´m wrong, but in this case i
>>think the best way to provide different
>>user access is to get the username and
>>password by using the command line
>>params ( String[] args ) - and i´m
>>looking for an effective way to check
>>those...
>>
>>Per wrote:
>>
>>>Maybe it would be an idea to use xml. You could make an xml file with
>>
> the
>
>>>setup condition and then use an xml parser like the one from ibm (free).
>>>Some of the validating could then be performed with the xml's dtd (this
>>
> validating
>
>>>is automatic performed by the ibm parser).
>>>
>>>If you make use of xml to hold the setup values it can esaly be changed
>>
> if
>
>>>you need other values to your application and you will have a great overview
>>>of the data.
>>>If you have not worked with xml and dtd it will take some time to understand
>>>it, but xml and java is working very good together and you will be able
>>
> to
>
>>>find a lot of java software on the net that can performe the parsing.
>>>
>>>To take a quick look at xml see
>>>http://www.w3schools.com/
>>>There is no java parser on this link.
>>>
>>>
>>>regards
>>>Per
>>>Volker Held <vheld@gwdg.de> wrote:
>>>
>>>
>>>>Hi,
>>>>
>>>>does anybody has a "good" example for
>>>>command line parameter checking?
>>>>
>>>>I write a lot of command line tools for
>>>>java, recently they have become more
>>>>complex and it´s required to check a
>>>>number of command line switches in order
>>>>to provide successfull execution of the
>>>>program.
>>>>
>>>>Now the checking in general is no
>>>>problem, but i´m uneasy about which
>>>>design approach to use...
>>>>
>>>>Until now i usually used an launcher
>>>>class that passes the command line args
>>>>to a "validating" module ( class ) that
>>>>also sets the class fields if the args
>>>>were correct.
>>>>I used to set the class fields in the
>>>>constructor of the "validating" class
>>>>and a lot more... that is i do a lot of
>>>>preparation/work in the constructor...
>>>>now i ask myself is that really a good
>>>>way to go or are there better/more
>>>>efficient ways...
>>>>
>>>>Thanks for any advice
>>>>
>>>>Volker
>>>>
>>>
>>>
>