Why is config admin checking for empty collections in Configuration values?

[David Jencks <da...@yahoo.com.INVALID>]

While writing a test I discovered that config admin doesn't like empty collections or collections with empty values as configuration values.  After searching the 5.0 config admin spec for a while I can't find any support for these restrictions, and they are not applied to arrays.  What is the justification for these checks?

Here's the code I'm asking about (CaseInsensitiveDictionary lines 309ff)

            if ( collection.isEmpty() )
            {
                throw new IllegalArgumentException( "Collection must not be empty" );
            }

            // ensure all elements have the same type and to internal list
            Collection internalValue = new ArrayList( collection.size() );
            type = null;
            for ( Iterator ci = collection.iterator(); ci.hasNext(); )
            {
                Object el = ci.next();
                if ( el == null )
                {
                    throw new IllegalArgumentException( "Collection must not contain null elements" );
                }


thanks
david jencks

Re: Why is config admin checking for empty collections in Configuration values?

[Felix Meschberger <fm...@adobe.com>]

Hi David

Hmm, good question. It has always been there - ever since it was first imported into the Felix project as part of FELIX-11.

While an empty collection does not make that much sense, I think the check doesn't either. On the other hand: If empty collections are allowed, then it must be made sure the ConfigurationHandler serializer can also read and write such empty collections.

Regards
Felix

Am 06.08.2014 um 03:35 schrieb David Jencks <da...@yahoo.com.INVALID>:

> While writing a test I discovered that config admin doesn't like empty collections or collections with empty values as configuration values.  After searching the 5.0 config admin spec for a while I can't find any support for these restrictions, and they are not applied to arrays.  What is the justification for these checks?
> 
> Here's the code I'm asking about (CaseInsensitiveDictionary lines 309ff)
> 
>            if ( collection.isEmpty() )
>            {
>                throw new IllegalArgumentException( "Collection must not be empty" );
>            }
> 
>            // ensure all elements have the same type and to internal list
>            Collection internalValue = new ArrayList( collection.size() );
>            type = null;
>            for ( Iterator ci = collection.iterator(); ci.hasNext(); )
>            {
>                Object el = ci.next();
>                if ( el == null )
>                {
>                    throw new IllegalArgumentException( "Collection must not contain null elements" );
>                }
> 
> 
> thanks
> david jencks

Re: Why is config admin checking for empty collections in Configuration values?

[Carsten Ziegeler <cz...@apache.org>]

I didn't find anything either, my first assumption was that there is a test
for this in the CT which doesn't seem to be the case either. So I guess
this check can be removed.

Carsten


2014-08-06 3:35 GMT+02:00 David Jencks <da...@yahoo.com.invalid>:

> While writing a test I discovered that config admin doesn't like empty
> collections or collections with empty values as configuration values.
>  After searching the 5.0 config admin spec for a while I can't find any
> support for these restrictions, and they are not applied to arrays.  What
> is the justification for these checks?
>
> Here's the code I'm asking about (CaseInsensitiveDictionary lines 309ff)
>
>             if ( collection.isEmpty() )
>             {
>                 throw new IllegalArgumentException( "Collection must not
> be empty" );
>             }
>
>             // ensure all elements have the same type and to internal list
>             Collection internalValue = new ArrayList( collection.size() );
>             type = null;
>             for ( Iterator ci = collection.iterator(); ci.hasNext(); )
>             {
>                 Object el = ci.next();
>                 if ( el == null )
>                 {
>                     throw new IllegalArgumentException( "Collection must
> not contain null elements" );
>                 }
>
>
> thanks
> david jencks




-- 
Carsten Ziegeler
Adobe Research Switzerland
cziegeler@apache.org