nested interfaces implemented by outer class...

[Mark McDowell]

I was looking on the javaworld site
(http://www.javaworld.com/javaworld/javatips/f_jw-javatip50.html) and
began to try and implement the ideas in the article. Here is the simple
code I attempted:

public class Loader implements LoadParam, SortParam {

public interface LoadParam {
public static final LoadType FROM_MEMORY = new LoadType(1);
public static final LoadType FROM_FLATFILE = new LoadType(2);
public static final LoadType FROM_DB = new LoadType(4);
final class LoadType {
private final int m_loadtype;
private LoadType(int aType) {
m_loadtype = aType;
}
}
}

public interface SortParam {
public static final SortType BY_CITY = new SortType(1);
public static final SortType BY_NAME = new SortType(2);
public static final SortType BY_NUMBER = new SortType(4);
final class SortType {
private final int m_sorttype;
private SortType(int aType) {
m_sorttype = aType;
}
}
}

/** Creates new Loader */
public Loader() {
}
}

However, when I compile it, I get this error:
TestParameterConstants/SiteLoader.java [17:12] cyclic inheritance
involving TestParameterConstants.SiteLoader
public interface LoadParameters {
TestParameterConstants/SiteLoader.java [29:12] cyclic inheritance
involving TestParameterConstants.SiteLoader
public interface SortParameters {
2 errors

Does anyone have ideas about why? I'm using Java SDK 1.3 with Forte.

Mark McDowell

[Amit Kulkarni]

I think you have not posted complete code ,but when I compile it
after I place all *public* classes/interfaces into separate files ,they
compile nicely with jikes but javac gives me

D:\java>javac *.java
sun.tools.java.CompilerError: illegal class modifiers
at
sun.tools.javac.SourceClass.assertModifiers(SourceClass.java:2059)
at sun.tools.javac.SourceClass.compileClass(SourceClass.java:2577)
at sun.tools.javac.SourceClass.compile(SourceClass.java:2039)
at sun.tools.javac.Main.compile(Main.java:567)
at sun.tools.javac.Main.main(Main.java:733)
error: An error has occurred in the compiler; please file a bug report
(http://java.sun.com/cgi-bin/bugreport.cgi).
1 error

"Mark McDowell" <m.mcd...@bigfoot.com> wrote in message
news:MPG.140603cee...@news.ic.ncs.com...

[Margalit Gur-Arie_elidan1]

This does not compile on my JSDK 1.3 either.

On JDK 1.2 it does compile after you fix the error in the first line,

public class Loader implements Loader.LoadParam, Loader.SortParam {

So maybe Sun has a new policy on the subject. I'm going to check the
what's new for 1.3 docs.

[Margalit Gur-Arie_elidan1]

> This does not compile on my JSDK 1.3 either.

> On JDK 1.2 it does compile after you fix the error in the first line,

> public class Loader implements Loader.LoadParam, Loader.SortParam {

> So maybe Sun has a new policy on the subject. I'm going to check the
> what's new for 1.3 docs.

Sure enough ! This behavior has been submitted as bug
http://developer.java.sun.com/developer/bugParade/bugs/4326631.html

But they insist it is not a bug, and refer you to the JLS 2nd Ed., saying
that:
"...the rule against cyclic inheritance has been extended to prohibit
a class or interface from "depending" on itself, directly or
indirectly........."

[Mark McDowell]

In article <966550043.960673@sj-nntpcache-3>, amku...@cisco.com says...

> I think you have not posted complete code ,but when I compile it
> after I place all *public* classes/interfaces into separate files ,they
> compile nicely with jikes but javac gives me

I did provide the entire .java file. The article was apparently written
before 1.3 and Sun made a change to disallow the "cyclic dependency"
where the interface was an inner interface to the class when the class
implements it. Oh, well. Thanks for your help.

Mark

[Mark McDowell]

In article <20000817...@elidan.icon-stl.net>, m...@elidan.icon-
stl.net says...

> Sure enough ! This behavior has been submitted as bug

> http://developer.java.sun.com/developer/bugParade/bugs/4326631.html=20

>
> But they insist it is not a bug, and refer you to the JLS 2nd Ed.,

> saying=20 that:

> "...the rule against cyclic inheritance has been extended to prohibit

> a class or interface from "depending" on itself, directly or=20
> indirectly........."
Thanks so much for the help. I was only trying to implement it exactly,
as it seemed to answer a problem I was working on and seemed to
encapsulate the information and provide type safety at the same time...

Sigh... :)

Mark