COLLECTION:
USING PROGRESS.Lang.*.
USING app.core.util.Node.

CLASS app.core.util.Collection:
  DEF private property currentNode AS Node NO-UNDO GET. private SET.
  DEF private property headNode AS Node NO-UNDO GET. private SET.
  DEF private property lastNode AS Node NO-UNDO GET. private SET.
  DEF public property OffEnd AS LOG NO-UNDO GET. private SET.

  CONSTRUCTOR Collection():
    THIS-OBJECT:currentNode = ?.
    THIS-OBJECT:headNode = ?.
    THIS-OBJECT:OffEnd = yes.
  END CONSTRUCTOR.

  METHOD public void AddObject(obj AS Object):
    DEF VAR newNode AS Node NO-UNDO.

    newNode = NEW Node(obj).
    IF THIS-OBJECT:headNode EQ ? THEN DO:
      THIS-OBJECT:headNode = newNode.
      THIS-OBJECT:currentNode = newNode.
      THIS-OBJECT:lastNode = newNode.
      THIS-OBJECT:OffEnd = no.
    END.
    ELSE DO:
      THIS-OBJECT:lastNode:SetNext(newNode).
      THIS-OBJECT:lastNode = newNode.
    END.
  END METHOD.

  METHOD public void NextNode():
    IF THIS-OBJECT:currentNode:NextNode() NE ? THEN DO:
      THIS-OBJECT:currentNode = THIS-OBJECT:currentNode:NextNode().
    END.
    ELSE DO:
      THIS-OBJECT:OffEnd = yes.
    END.
  END METHOD.

  METHOD public PROGRESS.Lang.Object GetObject():
    RETURN THIS-OBJECT:currentNode:GetObject().
  END METHOD.

  METHOD public void NodeReset():
    THIS-OBJECT:currentNode = THIS-OBJECT:headNode.
  END METHOD.
END CLASS.

NODE:
USING PROGRESS.Lang.*.

CLASS app.core.util.Node:
  DEF private property nextNode AS app.core.util.Node NO-UNDO GET. private SET.
  DEF private property nodeObject AS PROGRESS.Lang.Object NO-UNDO GET. private SET.

  CONSTRUCTOR Node(nodeObject AS PROGRESS.Lang.Object):
    THIS-OBJECT:nodeObject = nodeObject.
    THIS-OBJECT:nextNode = ?.
  END CONSTRUCTOR.

  METHOD public PROGRESS.Lang.Object GetObject():
    RETURN THIS-OBJECT:nodeObject.
  END METHOD.

  METHOD public app.core.util.Node NextNode():
    RETURN THIS-OBJECT:nextNode.
  END METHOD.

  METHOD public void SetNext(nextNode AS app.core.util.Node):
    THIS-OBJECT:nextNode = nextNode.
  END METHOD.
END CLASS.

USAGE:
   mycont = NEW Collection().
   mycont:AddObject(NEW Object()).
   mycont:AddObject(NEW Object()).
   mycont:AddObject(NEW Object()).
   myObj = mycont:GetObject().

   col-loop:
   REPEAT:
     IF mycont:OffEnd EQ yes THEN LEAVE col-loop.
     myObj = mycont:GetObject().
     mycont:NextNode().
     temphtml = temphtml + "<p>Another</p>".
   END.