RE: [DotGNU]Portable.NET Status 22 Feb 2003

[Thong \(Tum\) Nguyen]

> -----Original Message-----
> From: Rhys Weatherley [mailto:address@hidden
> Sent: Saturday, 22 February 2003 4:36 p.m.
> To: Thong (Tum) Nguyen; address@hidden
> Subject: Re: [DotGNU]Portable.NET Status 22 Feb 2003
> 
> On Saturday 22 February 2003 01:30 pm, Thong \(Tum\) Nguyen wrote:
> > Hi Rhys,
> >
> > I would like to help out with this one.
> >
> > Can we model it after the Java2 collections classes rather than the
.NET
> > ones?
> 
> Possibly.  I started with the C# collections, primarily because they
were
> familar to me and other C# programmers.  But the reason why I'm
opening
> this
> up now is so that we can discuss what the generic classes need to look
> like.
> All options are on the table.
> 
> > We can have ADTs like IStack, IQueue, IMap, IList with concrete
> > implementations like ArrayStack, LinkedStack, ArrayQueue,
LinkedQueue,
> > HashMap, TreeMap etc etc.
> >
> > System.Collections makes a mistake in that Stack and Queue are
concrete
> > class rather than interfaces.  This makes it hard to replace the
> > underlying implementations of the ADTs.
> 
> Well spotted.  Yes, that is a problem with the current C# collections.
Do
> you
> want to look into these, or at least give me a pointer to them?

I'll look into it next week (or perhaps over the weekend if I have
time).
Gyro will make it easier to test (at least until portable.net's generics
is complete).

I've had a bit of experience writing generic collections (in C++).
Here's what I hope the C# ones will look like:

ICollection (base interface for all collections)
|
* Add(T)
* AddAll(ICollection<T>)
* Clear
* Contains(ICollection<T>)
* ContainsAll(ICollection<T>)
* Remove(T)
* RemoveAll(ICollection<T>)
* RetainAll(ICollection<T>)
* GetIterator
* IsEmpty
* get_Count
* ToArray
|
+--AbstractCollection (base class for all collections)

  
IList
|
+--AbstractList (default implementations of some methods like AddAll)
   |
   +--ArrayList 
   |
   +--LinkedList
   |
   +--DoublyLinkedList  

IMap
|
+--AbstractMap
   |
   +--HashMap (hash based map)
   |
   +--TreeMap (binary tree based map)

IMapEntry
  * get_Key
  * get_Value


ISet
|
+--AbstractSet
   |
   +--MapBackedSet
      |
      +--HashSet (trivial)
      |
      +--TreeSet (trivial)

IStack
|
+--AbstractStack
   |
   +--ListBackedStack (stack that uses a provided IList implementation)
      |
      +--ArrayStack (trivial)
      |
      +--LinkedListStack (trivial)
      |
      +--DoublyLinkedListStack (trivial)

IQueue
|
+--AbstractQueue
   |
   +--ListBackedQueue (stack that uses any given IList implementation)
      |
      +--ArrayQueue (trivial)
      |
      +--LinkedListQueue (trivial)
      |
      +--DoublyLinkedListQueue (trivial)


All the trivial collections are easily implemented.  They simply call
the base (backing collection's) constructor :).  Once lists and maps are
implemented, stacks, queues and sets will be easy.

> 
> No matter what we do, we should have "Adapter" classes that can be
used to
> bridge the gap with the existing non-generic collection classes in C#.
> There
> are a lot of existing API's that expect ICollection, IEnumerable, etc.
> 

Definitely :).

Regards,

^Tum