Re: [Geotools-devel] More on calculator package

[Jan J. <h....@ce...>]

Thanks. The List wrapper seems to be the best approach . I will try to =
do so.=20
Cheers,
Jan.
______________________________________________________________
> Od: mar...@ge...
> Komu: Jan Jezek <h....@ce...>
> CC: geotools-devel <geo...@li...>
> Datum: 13.11.2006 18:35
> P=F8edm=ECt: Re: [Geotools-devel] More on calculator package
>
>Jan Jezek a =E9crit :
>> * Make Inner class under MappedTriangulatioFactory that will look li=
ke
old MappedPosition and will be used just for generating map of source a=
nd
destination triangles.
>> OR
>> * Rewrite TriangulationFactory  to be able to work with new
MappedPosition instead of DirectPosition.
>> > I prefer the first approach, but may be you can help me how to do
this better.
>> So what do you think?
>
>
>A third approach is to make MappedPosition extends DirectPosition2D (o=
r
GeneralDirectPosition) like you did :). But while convenient to impleme=
nt,
I'm not sure if it is conceptually correct or not. For now I'm not sure
because I don't know yet the full builder code enough. This is why the =
old
MappedPosition is still around for now.
>
>An other approach which should be efficient and avoid copy is:
>
>   * Changes the Triangulation factory code in order to work with
>     List<DirectPosition> instead of array of type DirectPosition[].
>
>   * Write a small class like the one below:
>
>class MappedPositionList<DirectPosition> extends AbstractList {
>     private final List<MappedPosition> positions;
>
>     MappedPositionList(List<MappedPosition> positions) {
>         this.positions =3D positions;
>     }
>
>     public int size() {
>         return positions.size();
>     }
>
>     public DirectPosition get(int index) {
>         MappedPosition p =3D positions.get(index);
>         return p.getTargetPoint();
>     }
>}
>
>
>Thats all. As you can see, writing List wrappers is pretty easy (we ar=
e
probably going to have a bunch of casts in the code with J2SE 1.4 inste=
ad
of 1.5). We may add a 'boolean' argument in order to select between sou=
rce
and target points. With such wrappers, there is no copy operation at al=
l -
we just create different "view" of the mapped position list. This view =
can
be given to the triangulation factory methods.
>
>Thats why I usually like to recommand usage of Collections over arrays=
 in
API.
>
>What do you think?
>
>	Martin
>