IIRC, there has been some discussion among Drools developers<br>to add this instanceof test automatically. But right now, the<br>instanceof is required - not necessarily in the posted way.<br><br>(1) Whether a Step object contains L as a subset<br>
of its List<DescribedAddress> or in any other way should not be<br>exposed to the clients of this class. So, add a<br> List<VendorAddress> getVendorAddresses() <br>to Step and hide the dirty details where they belong.<br>
<br>(2) With or without (1), in this particular situation, an accumulate<br>would be indicated which determines the VendorAddress with<br>maximum abcScore in one pass over all objects.<br><br>-W<br><br><div class="gmail_quote">
On 26 August 2011 22:04, lhorton <span dir="ltr"><<a href="mailto:LHorton@abclegal.com">LHorton@abclegal.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
The following code works, but I think it's ugly.<br>
<br>
the classes are:<br>
DescribedAddress is a base class for addresses<br>
VendorAddress extends DescribedAddress and implements method abcScore()<br>
Step getLocations() is defined as a list of DescribedAddress objects but it<br>
can also contain VendorAddress objects since they are a kind of<br>
DescribedAddress<br>
<br>
the LHS of the rule below extracts the VendorAddress with the highest<br>
abcScore from step.locations<br>
<br>
if I omit the eval(), i get ClassCastException on any DescribedAddress in<br>
locations, since DescribedAddress cannot be cast to VendorAddress.<br>
<br>
is there a more elegant / clean / efficient way to get only the<br>
VendorAddress objects from locations?<br>
<br>
rule "Find highest scored address"<br>
dialect "mvel"<br>
when<br>
$step : Step()<br>
$location : VendorAddress (eval($location instanceof VendorAddress ),<br>
abcScore>9) from $step.getLocations()<br>
<br>
not $addr : VendorAddress (eval($addr instanceof VendorAddress<br>
),abcScore > $location.abcScore) from $step.getLocations()<br>
<br>
then<br>
System.out.println("high score is: " + $location.getAbcScore());<br>
end<br>
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