[rules-users] Are there second-rate fact types?

[Wolfgang Laun]

On 10/06/2014, Davide Sottara <dsotty at gmail.com> wrote:
> java.util.Collections (and descendants) are not @typesafe by default,
> I'll check the reason for that.

OK.

> More generally, if a fact is declared as not @typesafe, the runtime
> failure should be more graceful.

But (according to you)  java.util.Collections is *not* @typesafe, and
this runtime failure cannot be called "graceful".

Can a java.util.X be declared as @typesafe? If so, how? Is any of this
documented anywhere?

-W

> Davide
>
> On 06/10/2014 01:26 PM, Wolfgang Laun wrote:
>> Consider:
>>
>>    class Foo { /*...*/ }
>>
>>    rule checkFoo
>>    when
>>       Foo( noSuchField > 0 )
>>    then ... end
>>
>> DRL compilation reports an error (Error: unable to resolve method ...)
>> and identifies rule, line and column, which is fine.
>>
>> Now let's look at:
>>
>>    import java.util.ArrayList;
>>    rule checkArrayList
>>    when
>>       ArrayList( noSuchField > 0 )
>>    then ... end
>>
>> The same DRL compiler (checked with 5.5.0 and 6.0.0) accepts this, and
>> there is a nasty exception thrown at runtime. This is inconvenient,
>> since the exception can be thrown by any code inserting an ArrayList
>> object, and the faulty rule isn't identified.
>>
>> Why are certain classes second-rate?
>>
>> -W
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>>
>
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