Re: ArrayList called with specific object constructors

From:

Zio Jerry <ale.mito@tiscali.it>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 29 Apr 2009 01:25:14 -0700 (PDT)

Message-ID:

<1d1b278a-cece-474a-bde2-f1d88e3a4c8b@a5g2000pre.googlegroups.com>

On 29 Apr, 02:59, Lew <no...@lewscanon.com> wrote:

Alessandro wrote:

The idea is that you want to be able to use a factor of Integers (e.g.=

)

to fill a list of Numbers. The other way of doing this is to do this:
public <T> List<? super T> makeList(Factory<T> factory)

That's clear, but I have problems with calling the interface Factory.
Still viewed Robert code but it can't work because instantiating an
interface.

You don't instantiate interfaces. You instantiate a concrete class and=

assign

its reference to an interface-typed variable.

This is my edited fragment:

//START
*** Factory interface ***
public interface Factory<T> {
public T makeObject(String s1, String s2);
}
*** class calling generic method (implements Factory ??? implements
Factory<T> ???***
...
ArrayList<Ric> ricList=xmlService.xml2ListGEN(new Factory<Ric>());

Nope. Instead of 'new Factory <Ric>()' try something like Robert Klemm=

e's

anonymous class trick, or define a named class like:

public class RicFactory implements Factory <Ric>
{
   public Ric makeObject( String s1, String s2 )
   {
     return new Ric( s1, s2 );
   }}

====
  List <Ric> rics = makeList( new RicFactory() );
  ...

--
Lew

Many thanks, now that's all clear and working !
Thanks also to all people have contributed about this post.

Alessandro