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Re: Best Way® to test for existence of a relationsh ip
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Re: Best Way® to test for existence of a relationsh ip


  • Subject: Re: Best Way® to test for existence of a relationsh ip
  • From: Chuck Hill <email@hidden>
  • Date: Mon, 7 Apr 2008 07:22:37 -0700

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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Bob Stuart
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  • Follow-Ups:
    • Re: Best Way® to test for existence of a relationsh ip
      • From: Mike Schrag <email@hidden>
References: 
 >Best Way® to test for existence of a relationship (From: David Avendasora <email@hidden>)
 >Re: Best Way® to test for existence of a relationsh ip (From: Bob Stuart <email@hidden>)

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