Re: Extending Inner Classes

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 08 Nov 2007 09:26:54 -0500
Message-ID:
<k7qdnf-Ag-Yyga7anZ2dnUVZ_u2mnZ2d@comcast.com>
RFleming@NationalSteel.com wrote:

I have a package Some Data.
     A Class DataGroup1
         A Method public ParseData getParseData
                 ParseData retValue = new ParseData(args,args....);
                 return retValue;

         A Public Static InnerClass ParseData
            A Method Public getParsedData

     A Class DataGroup2 extends DataGroup1
         A Method public ParseData getParseData
                 ParseData retValue = new ParseData(args,args....);
                 return retValue;

         A Public Static InnerClass ParseData
            A Method Public getParsedData


I am not able to compile your example.
<http://www.physci.org/codes/sscce.html>

There is no such thing as a "static inner class". An inner class is not
static, by definition. You mean a static nested class.

The problem I am getting is I cannot seem to overide the superclasses
method as DataGroup1.ParseData is a different return type than
DataGroup2.ParseData. Am I doint something impossible as it is layed
out above?


I cannot say because you have not provided any code, but it looks wrong on the
face of it. You say "ParseData()" is a method, but you spell it with an
initial upper-case letter and indicate constructor syntax for it, which means
it's a class and not a method. You have "ParseData" in every outer and nested
class. You don't show the subclass is supposed to use ParseData, nor which
one it's supposed to use. Your example is a mess.

Review
<http://www.physci.org/codes/sscce.html>
and try again.

I thought about making the inner class it's own separate class in the package, but if I do I would prefer it was 'protected' to
be only viewable to classes in that package and do not know how to
accomplish that.


You can make it a top-level class and declare it as package-private (no access
modifier whatsoever). It can even be in the same source file as a public
class, although that's probably not wise.

I could also just make the inner class part of the DataGroup Classes, but that would require some serious re-coding.


Your outline suggest that you've already made the (not inner) nested class
part of the DataGroup class(es?).

Any suggestions, or hints would be greatly appreciated!


Provide an example we can actually run through our compilers.
<http://www.physci.org/codes/sscce.html>

More importantly, tell us what you're trying to accomplish. Not the specific
strategy of overriding ParseData, whatever you think that might mean, but the
goal of what such an ovverride is supposed to accomplish. If we don't know
what you're trying to accomplish it's hard to help.

<http://www.physci.org/codes/sscce.html>

--
Lew

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