[rules-dev] need advice re null handling

[Mark Proctor]

Its not about giving it up, its how we handle when those fields are 
null, do we treat it like a primitive and assume its 0, or do we say it 
can't be equal to anything else but null.

In the following example neither y or z is defined, thus y is null and z 
is 0;

int x = 0;
Integer y;
in z;
x == y // is false;
x == z // is true
y == null // is true

Mark

Tom Gonzalez wrote:
> The flexibility provided by an Object is very valuable. We use Integer 
> and String objects all over the place today in our facts with drools. 
> I would hate to give it up.
>  
> Tom G
>
> ------------------------------------------------------------------------
> *From:* rules-dev-bounces at lists.jboss.org 
> [mailto:rules-dev-bounces at lists.jboss.org] *On Behalf Of *Mark Proctor
> *Sent:* Thursday, March 15, 2007 6:29 AM
> *To:* Rules Dev List
> *Subject:* Re: [rules-dev] need advice re null handling
>
> if bar is an integer it will be 0, if its an Integer it will be null. 
> The Q is do we make Integer work like the primitive, or do we make it 
> work like an Object.
>
> Mark
> Michael Neale wrote:
>> http://jira.jboss.com/jira/browse/JBRULES-627
>>
>> OK, this much is clear:
>>
>> Foo(field == null) can be true if field is null.
>>
>> but, what about Foo(field > 3), and field is null? should that be 
>> false? what about Foo(field != 3) - should that be true?
>>
>> in SQL, null will always result in a false condition, unless you 
>> explicitly use null.
>>
>> Thoughts?
>>
>> Michael.
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>>
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