GenericsType

[Alex Tkachman]

Hi!

Does anybody know why do we have


    public ClassNode getLowerBound() {
        return lowerBound;
    }

but

    public ClassNode[] getUpperBounds() {
        return upperBounds;
    }

One type in 1st case instead of array at the second

Best regards
Alex

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[Jochen Theodorou]

Alex Tkachman schrieb:

> Hi!
>
> Does anybody know why do we have
>
>
>     public ClassNode getLowerBound() {
>         return lowerBound;
>     }
>
> but
>
>     public ClassNode[] getUpperBounds() {
>         return upperBounds;
>     }
>
> One type in 1st case instead of array at the second

 From
http://www.angelikalanger.com/GenericsFAQ/FAQSections/TypeArguments.html#FAQ203
"""
A wildcard can have only one bound, either  a lower or an upper bound.
A list of wildcard bounds is not permitted.

A type parameter, in contrast, can have several bounds, but there is no
such thing as a lower bound for a type parameter.
"""

According to the second one there is no such thing as a lower bound for
a type parameter so I assumed upper bounds, and an array of them

<T extends GroovyObject & Runnable & Clonable>

would be an example. I think we don't check, that you can have at most
one class in there.

bye blackdrag

--
Jochen "blackdrag" Theodorou
The Groovy Project Tech Lead (http://groovy.codehaus.org)
http://blackdragsview.blogspot.com/


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[Alex Tkachman]

Wow, thanks a lot.
I totally forgot that if ever knew.

On Wed, Oct 21, 2009 at 1:14 PM, Jochen Theodorou <blackdrag@...> wrote:

> Alex Tkachman schrieb:
>>
>> Hi!
>>
>> Does anybody know why do we have
>>
>>
>>    public ClassNode getLowerBound() {
>>        return lowerBound;
>>    }
>>
>> but
>>
>>    public ClassNode[] getUpperBounds() {
>>        return upperBounds;
>>    }
>>
>> One type in 1st case instead of array at the second
>
> From
> http://www.angelikalanger.com/GenericsFAQ/FAQSections/TypeArguments.html#FAQ203
> """
> A wildcard can have only one bound, either  a lower or an upper bound. A
> list of wildcard bounds is not permitted.
>
> A type parameter, in contrast, can have several bounds, but there is no such
> thing as a lower bound for a type parameter.
> """
>
> According to the second one there is no such thing as a lower bound for a
> type parameter so I assumed upper bounds, and an array of them
>
> <T extends GroovyObject & Runnable & Clonable>
>
> would be an example. I think we don't check, that you can have at most one
> class in there.
>
> bye blackdrag
>
> --
> Jochen "blackdrag" Theodorou
> The Groovy Project Tech Lead (http://groovy.codehaus.org)
> http://blackdragsview.blogspot.com/
>
>
> ---------------------------------------------------------------------
> To unsubscribe from this list, please visit:
>
>   http://xircles.codehaus.org/manage_email
>
>
>

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