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Re: Object Oriented Subclassing Question
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Re: Object Oriented Subclassing Question


  • Subject: Re: Object Oriented Subclassing Question
  • From: Jonathan Rochkind <email@hidden>
  • Date: Mon, 8 Mar 2004 11:46:05 -0600

[I've restricted my reply to just one list. I have a personal pet peeve against cross posting to both lists].

The idea of 'overriding' _variables_ in Java is a confusing one. You can't really over-ride variables in Java. By giving a variable the same name in a sub-class and a super-class, you've "shadowed" the superclass implementation, not over-ridden it. The super-class variable is still there, it's just kind of hidden.

The whole thing has never made much sense to me, so I can't explain it very well. I try to avoid the need to deal with it, by over-ridding _methods_, which work as expected, and leaving variables alone.

But look up info on the web about Java and variables and "shadowing" and such. Or get a book on Java. Here's one web page, just the first one I find on Google:
http://java.sun.com/developer/TechTips/2000/tt1010.html#tip2


--Jonathan

At 1:18 PM -0600 3/6/04, James Cicenia wrote:
Hello -

I have a component called EditLists and I want to subclass it
for each of my lists.  i.e. EditRoles, EditSystems, etc.

at the top of my EditLists class I have:

	/** @TypeInfo eo.PortfolioRole */
	public PortfolioRole newItem;
	public PortfolioRole theItem;
	public String QUERY_DELETE_VALUE = "rosterMembers.role.value";
	public String QUERY_OBJECT = "PortfolioRole";


Can I override those public variables? It seems I can't. My component thinks the subclass is actually the superclass. Newbie OO question I am sure, but would like to understand this pattern a bit more. I just need to change those and everything should work great.

-James Cicenia



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References: 
 >Object Oriented Subclassing Question (From: James Cicenia <email@hidden>)

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