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Re: Educate me on generics please...
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Re: Educate me on generics please...


  • Subject: Re: Educate me on generics please...
  • From: Ian Joyner <email@hidden>
  • Date: Thu, 7 Feb 2008 10:46:08 +1100

On 07/02/2008, at 9:20 AM, James Cicenia wrote:

Hmmm,

And to think I learned that method of qualifier creation from either a book or Apples own docs years ago.

But mixing the objects in the List was confusing me, which is what Johann said about just using <Object>

That's probably why Java recommends using Interfaces as your generic types – interfaces have multiple inheritance (generics really need real multiple inheritance, not this weak interface stuff). You use the type as the generic that has the common routines that you need to process all the objects in the collection.


In the key/value example there is really nothing in common between the key (a string) and the value (an arbitrary object). But you would probably be better off using a dictionary <k, v>, but I guess that is not the way EOF is designed, so hence generics are not very useful in this example.

Ian


-j-

On Feb 6, 2008, at 3:52 PM, Mr. Pierre Frisch wrote:

I completely disagree on this one. Your example is bad as it mixes different type of objects in the List. The point of generics is to catch type cast exception at compile time instead of run time. if you mix objects in the same array then it has no value but this is bad style anyway.

Pierre
--
Pierre Frisch
email@hidden


On Feb 6, 2008, at 12:37, Chuck Hill wrote:


On Feb 6, 2008, at 12:33 PM, James Cicenia wrote:

Well I have decided to to start going to 1.5 now.

this is something I do all the time:

NSMutableArray args2 = new NSMutableArray();
args2.addObject("portfolio");
args2.addObject(portfolio);
myQualifier2 = EOQualifier.qualifierWithQualifierFormat("%@ = %@", args2);

NSArray results = EOQualifier .filteredArrayWithQualifier(portfolioUserGroups(),myQualifier2);


How do I make that "generic Java 1.5" friendly?


From Art:

http://weblogs.java.net/blog/arnold/archive/2005/06/generics_consid_1.html
http://www.mindview.net/WebLog/log-0050

YMMV  :-)

Chuck

--

Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems.
http://www.global-village.net/products/practical_webobjects






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References: 
 >Educate me on generics please... (From: James Cicenia <email@hidden>)
 >Re: Educate me on generics please... (From: Chuck Hill <email@hidden>)
 >Re: Educate me on generics please... (From: "Mr. Pierre Frisch" <email@hidden>)
 >Re: Educate me on generics please... (From: James Cicenia <email@hidden>)

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