🚀 go-pugleaf

On Fri, 29 Dec 2000 22:51:29 -0000, Niall Pemberton wrote:

> your table cell renderer is strange...I'm not an expert but I
> don't think you need a setValue() method in it ... you need to
> implement a getTableCellRendererComponent() method as below,

James's renderer is derived from DefaultTableCellRenderer, which 
provides the getTableCellRendererComponent() method, and uses the 
setValue() method to get the cell value.  It also sets the foreground 
and background colors and draws selection borders.

But I much prefer your code, since a renderer is pretty easy to write 
from scratch, and DefaultTableCellRenderer does not really help much, 
especially if you want to change the foreground and background colors.  
I have also found that it gets in the way at times.

But you might want to look at the code for DefaultTableCellRenderer to 
see how it implements the getTableCellRendererComponent() method.  
There are some optimizations that it does that can make a difference in 
rendering performance.

> On the subject of initialising the values, you don't have to
> do it. Set up your own Table Model as below, using a HashMap
> to only store values when you actually have one:

I agree that it is better to not store the PcCharacter values for 
"empty" cells (see my other message).  But for efficiency, I would use 
a two dimensional array to store the values rather than a HashMap.

The HashMap might make a lot of sense if the size of the table was 
unbounded, or it was *very* sparse.  But I don't think the added 
overhead of a HashMap makes sense in this case, since the table size is 
fixed and probably not that sparse.

The HashMap implementation also has some allocations that would occur 
during rendering, while the array implementation has no additional 
allocations.  Please note that I think it is seldom a good idea to 
sacrifice the clarity of the code or design in the name of efficiency, 
but the array implementation is at least as clear as a HashMap, and I 
think that rendering code is one place where a little extra attention 
to performance makes sense.

-- 
Regards,

John McGrath [TeamB]

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