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Posted to users@felix.apache.org by Bart Elen <Ba...@cs.kuleuven.be> on 2007/09/12 17:43:09 UTC

How to check if an optional package is available?

Hello,


When a package is imported with 'resolution:=optional', we have to check if the package is available 
or not before we use it. But how do we do this?

Someone has experience with this problem?



Thanks,

Bart

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Re: How to check if an optional package is available?

Posted by Bart Elen <Ba...@cs.kuleuven.be>.

Thanks for the help Richard!

This solution works.


Greetings,

Bart


Richard S. Hall wrote:
> Bart Elen wrote:
>> Hello,
>>
>>
>> When a package is imported with 'resolution:=optional', we have to 
>> check if the package is available or not before we use it. But how do 
>> we do this?
>>
>> Someone has experience with this problem?
> 
> Just try to load a class from that package and catch any exceptions...if 
> you load the class successfully, then the package is available, if not 
> then don't try to load any more, e.g.:
> 
>    boolean fooAvailable = false;
>    try {
>        this.getClass().getClassLoader().loadClass("org.foo.MyClass");
>        fooAvailable = true;
>    } catch (Exception ex) {
>        // foo is not available.
>    }
> 
> Something like that.
> 
> -> richard
> 
>>
>>
>>
>> Thanks,
>>
>> Bart
>>
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>> To unsubscribe, e-mail: users-unsubscribe@felix.apache.org
>> For additional commands, e-mail: users-help@felix.apache.org
>>
> 
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Re: How to check if an optional package is available?

Posted by "Richard S. Hall" <he...@ungoverned.org>.

Bart Elen wrote:
> Hello,
>
>
> When a package is imported with 'resolution:=optional', we have to 
> check if the package is available or not before we use it. But how do 
> we do this?
>
> Someone has experience with this problem?

Just try to load a class from that package and catch any exceptions...if 
you load the class successfully, then the package is available, if not 
then don't try to load any more, e.g.:

    boolean fooAvailable = false;
    try {
        this.getClass().getClassLoader().loadClass("org.foo.MyClass");
        fooAvailable = true;
    } catch (Exception ex) {
        // foo is not available.
    }

Something like that.

-> richard

>
>
>
> Thanks,
>
> Bart
>
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> To unsubscribe, e-mail: users-unsubscribe@felix.apache.org
> For additional commands, e-mail: users-help@felix.apache.org
>

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