I'd expect the instanceof check will be much more efficient than
catching an exception. From an OO design point of view, I'd add a
billsOfMaterial() method to the Part class that simply returns
NSArray.emptyArray. ManufacturedPart will then override this to
return the correct result for a ManufacturedPart.
Chuck
On Apr 7, 2008, at 6:34 AM, Bob Stuart wrote:
Try catch seems expensive to me. Why not just check with
if (aPart instanceof ManufacturedPart){
do something with aPart.billsOfMaterial()
}
At 9:12 AM -0400 4/7/08, David Avendasora wrote:
Hi all,
This is more of a Java question than a WO-specific one
I have an Inheritance structure in my app:
Part (abstract Superclass)
RawMaterial (subclass of Part)
ManufacturedPart (subclass of Part)
I have an NSArray of Parts that could be, RawMaterial instances,
ManufacturedPart instances, or most likely, a mixture of the two.
I want to iterate through the Array and get the contents of the
Part.billsOfMaterial() (toMany) relationship. The problem is that
while ManufacturedParts have this relationship, RawMaterials do not.
Right now, I'm using a try-catch block that catches the exception
on RawMaterial.billsOfMaterial() and just ignores it.
I could also add a billsOfMaterial() method to the RawMaterial
class that simply returns NSArray.emptyArray.
Is one way better than the other for any reason?
Thanks,
Dave
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