Re: ArrayList called with specific object constructors

From:
Zio Jerry <ale.mito@tiscali.it>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 29 Apr 2009 02:33:44 -0700 (PDT)
Message-ID:
<5d18113c-017d-4745-bc8a-0781004ce2a3@n7g2000prc.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


Thanks for your code, it has solved all my problems !
Thanks also to all the people who has answered to this post.

Alessandro

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