[rules-users] Using field values of an ENUM in the decision table

[Viswanathan Nageswaran]

Erik,

Thanks for your comment. In your suggestion, you have compared the memory
field with MEM.CONST1 and are setting the price to MEM.value.
But, the requirement is to restrict the field memory with the value of
CONST1 (like 512, 1024, 2048) in the decision table and based on that set
the price which is not really an attribute of the CONST MEM.CONST1 (so
MEM.getValue() doesn't fetch the price), but is a set of pre defined values
mapped to the actual memory values.

If someone in this group has used ENUMs in Decision tables, I would be very
interested in those examples. Can you share the same? Please.

Thanks in advance,
-Visu



                                                                           
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             08/07/2009 22:55          Re: [rules-users] Using field       
                                       values of an ENUM in the decision   
                                       table                               
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Are you sure you have to have a Memory object inserted as a fact ?

Don't this rule works (not tested and I'm so not a drools expert)

rule "memory"
 when
  $c : Computer(memory == MEM1 || memory == MEM2 || memory == MEM3)
 then
  modify($c) { setPrice(MEM1.getValue() };
 end



On Wed, 8 Jul 2009 09:50:16 -0700 (PDT), Visu Nageswaran
<visu.nageswaran at in.ibm.com> wrote:
> I was able to achieve this using a join-column in the decision table
> equivalent to the below rule:
> WHEN $m: Memory(value == "512") $c: Computer(memory == $m)
> THEN modify($c){ setPrice(100) };
>
> However, a Memory instance needs to be inserted into the session. For
every
> discrete valued field, it would then be required for them to be inserted
> into the session to be considered in rule propogation. If there is a
better
> way / simpler way, I am very interested. Thanks in advance..
>
>
> Visu Nageswaran wrote:
>>
>> Hello, I am posting a simpler version of the actual requirement:
>> Class Computer has a field 'memory' of the enum type 'Memory' which is
>> defined over integer values
>> - - - - - - - - - -
>> public enum Memory{
>> MEM1(512), MEM2(1024), MEM3(2048);
>> public int value;
>> Memory(int i){this.value = i;}
>> public int getValue(){return value;}
>> }
>> - - - - - - - - - -
>> There is a requirement to model a decision table between memory and
price
>>
>> I am looking for the field constraint on the memory field to match to
the
>> values:
>>
>> memory.???--> Price
>> 512 --> 100
>> 1024 --> 200
>> 2048 --> 300
>>
>> I tried memory.name, memory.name(), memory.value, memory.getValue();
Does
>> this have to be done using template expressions say something like
memory
>> == Memory.reverseLookupEnum($param)
>>
>> Any help, pointers in this regard would be appreciated. thanks.
>> -Visu
>>
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