Pagination of results.

Question

Hi All,
Just wondering if anyone has come across a nice way to do pagination of results from a database call. I am getting back a populated container object (extended from Vector, for which I have no control over) in my jsp. I only want to display 10 objects from the container object per page (potentially it could contain 100's of objects). The user needs to be able to go back and forth through the pages as they wish. Any ideas or gotcha's that I should be aware of.
Cheers,
James.
P.S. Would it be easier if I was given the actual ResultSet object from the DB lookup.

Answer 1

I'm not gonna give you the code because it's a nice problem to work out but here's the way I did it:
Write a class called Pager
the constructor takes a Vector of all the objects you're paging over, the number of items you want on the page and the current page.
From there you can splice the Vector into the sublist that you need for the current page.
From there all you need to do is write a few simple methods:
void moveFirst()
void moveNext()
void moveLast()
void moveTo()
int getNumItems()
getCurrent() -> returns whatever you're storing in your Vector
boolean eof()
boolean hasMorePages(Vector allItems)
boolean hasPrevPages()
int getNextPage(int currentPage)
int getPrevPage(int currentPage)
int getStart()
int getEnd()
int getTotalPages(Vector allItems, int pageSize)
int getItemCount()
Good Luck