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Posted to dev@commons.apache.org by Henri Yandell <ba...@generationjava.com> on 2003/12/31 21:28:26 UTC

[beanutils] BeanComparator wrapping NullComparator?

Currently BeanComparator will fall over on a null, as
'testCompareWithNulls' unit test shows.

Is there a lot of objection to making it more user friendly and making it
wrap NullComparator instead of ComparableComparator so that nulls do not
break?

[NullComparator wraps ComparableComparator by default].

Hen


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Re: [beanutils] BeanComparator wrapping NullComparator?

Posted by robert burrell donkin <ro...@blueyonder.co.uk>.
i think i'd expect the default implementation to gracefully cope with 
null's. null's first or nulls last is an arbitrary choice and most 
users would probably prefer to accept this than null. i suspect that 
there may be some wrinkles making this work properly.

- robert

On 31 Dec 2003, at 21:07, Henri Yandell wrote:

>
> Dunno. If I supply my own Comparator to BeanComparator, I think it's 
> up to
> me as to whether it blows up. "No magic".
>
> For the first/last question, it's easy. Use whathever NullComparator 
> does
> by default. Someone is always free to specify NullComparator(true) as a
> comparator to beancomparator.
>
> Or they can specify ComparableComparator as an argument to make Null's
> blow, but I reckon the average user will want the gentlest choices to 
> be
> made, without restricting their option to choose otherwise.
>
> Hen
>
> On Wed, 31 Dec 2003, Tim O'Brien wrote:
>
>> I know that some have objected to this in the past, but I think this 
>> is a
>> good idea.
>>
>> I think that BeanComparator should work with nulls
>> "out-of-the-box" the question arises - are nulls first or last?   
>> There is
>> an old issue that deals with this:
>> http://issues.apache.org/bugzilla/show_bug.cgi?id=18791
>>
>> I'm of the opinion that it isn't necessarily straightforward to wrap
>> NullComparator.  I think people expect BeanComparator *not* to blow 
>> up on
>> a null property value, and it would be generally easy to implement.
>>
>> Tim
>>
>>
>> On Wed, 31 Dec 2003, Henri Yandell wrote:
>>
>>>
>>> Currently BeanComparator will fall over on a null, as
>>> 'testCompareWithNulls' unit test shows.
>>>
>>> Is there a lot of objection to making it more user friendly and 
>>> making it
>>> wrap NullComparator instead of ComparableComparator so that nulls do 
>>> not
>>> break?
>>>
>>> [NullComparator wraps ComparableComparator by default].
>>>
>>> Hen
>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
>>> For additional commands, e-mail: commons-dev-help@jakarta.apache.org
>>>
>>>
>>>
>>
>> --
>> ----------------------
>> Tim O'Brien
>> Evanston, IL
>> (847) 863-7045
>> tobrien@discursive.com
>>
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
>> For additional commands, e-mail: commons-dev-help@jakarta.apache.org
>>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
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>


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Re: [beanutils] BeanComparator wrapping NullComparator?

Posted by Henri Yandell <ba...@generationjava.com>.
Dunno. If I supply my own Comparator to BeanComparator, I think it's up to
me as to whether it blows up. "No magic".

For the first/last question, it's easy. Use whathever NullComparator does
by default. Someone is always free to specify NullComparator(true) as a
comparator to beancomparator.

Or they can specify ComparableComparator as an argument to make Null's
blow, but I reckon the average user will want the gentlest choices to be
made, without restricting their option to choose otherwise.

Hen

On Wed, 31 Dec 2003, Tim O'Brien wrote:

> I know that some have objected to this in the past, but I think this is a
> good idea.
>
> I think that BeanComparator should work with nulls
> "out-of-the-box" the question arises - are nulls first or last?   There is
> an old issue that deals with this:
> http://issues.apache.org/bugzilla/show_bug.cgi?id=18791
>
> I'm of the opinion that it isn't necessarily straightforward to wrap
> NullComparator.  I think people expect BeanComparator *not* to blow up on
> a null property value, and it would be generally easy to implement.
>
> Tim
>
>
> On Wed, 31 Dec 2003, Henri Yandell wrote:
>
> >
> > Currently BeanComparator will fall over on a null, as
> > 'testCompareWithNulls' unit test shows.
> >
> > Is there a lot of objection to making it more user friendly and making it
> > wrap NullComparator instead of ComparableComparator so that nulls do not
> > break?
> >
> > [NullComparator wraps ComparableComparator by default].
> >
> > Hen
> >
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
> > For additional commands, e-mail: commons-dev-help@jakarta.apache.org
> >
> >
> >
>
> --
> ----------------------
> Tim O'Brien
> Evanston, IL
> (847) 863-7045
> tobrien@discursive.com
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: commons-dev-help@jakarta.apache.org
>


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Re: [beanutils] BeanComparator wrapping NullComparator?

Posted by Tim O'Brien <to...@discursive.com>.
I know that some have objected to this in the past, but I think this is a 
good idea.  

I think that BeanComparator should work with nulls 
"out-of-the-box" the question arises - are nulls first or last?   There is 
an old issue that deals with this:
http://issues.apache.org/bugzilla/show_bug.cgi?id=18791

I'm of the opinion that it isn't necessarily straightforward to wrap 
NullComparator.  I think people expect BeanComparator *not* to blow up on 
a null property value, and it would be generally easy to implement.

Tim


On Wed, 31 Dec 2003, Henri Yandell wrote:

> 
> Currently BeanComparator will fall over on a null, as
> 'testCompareWithNulls' unit test shows.
> 
> Is there a lot of objection to making it more user friendly and making it
> wrap NullComparator instead of ComparableComparator so that nulls do not
> break?
> 
> [NullComparator wraps ComparableComparator by default].
> 
> Hen
> 
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: commons-dev-help@jakarta.apache.org
> 
> 
> 

-- 
----------------------
Tim O'Brien
Evanston, IL
(847) 863-7045
tobrien@discursive.com



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