A Java 5 question

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Aleksandar Pecanov - 05 Apr 2005 16:47 GMT

Hi

( This is the first time to post something to the newsgroup so please
don't be harsh )
This is not exactly a problem, I'm just trying to figure out some things
in JDK 5. I have the following method:

public boolean addClass( Class c ) {
if( !c.isAnnotationPresent( SomeAnnotation.class ) )
throw new InvalidJdbcObjectException("Missing annotation for type: "+c);
...
}

... now, in the second line a warning is indicated: "The method
isAnnotationPresent(Class) belongs to the raw type Class. References to
generic type Class<T> should be parameterized"...
Is there a way of avoiding this warning through a standard procedur
(withoud compiler params, just code workaround or something).

Thank you.

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Tor Iver Wilhelmsen - 05 Apr 2005 22:40 GMT

> if( !c.isAnnotationPresent( SomeAnnotation.class ) )

Your use is consistent with Sun's example at

http://java.sun.com/j2se/1.5.0/docs/guide/language/generics.html

despite the JLS saying that Foo.class is of the ungeneric type
"Class".

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Fred - 06 Apr 2005 14:40 GMT

So why not parameterize the parameter?

public boolean addClass( Class<? extends Object>c ) would be somewhat
flexible. Or if you know the type of class that will be used as an
argument, that'd be even more appropriate (i.e. Class<this_type> c ).

That's just off the cuff, though, which is to say I've not tried to
compile either.

-Fred

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A Java 5 question

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