Re: efficiency of JList setElementAt()

Raymond Cruz wrote: 
I have an application that displays about 130 text lines in a scrollable
JList via the DefaultListModel.  Approximately 1 entry is modified each
second which is done by determining the position of the item and invoking
setElementAt of the DefaultListModel object.  My Athlon XP-1800+ machine
consumes 31% of the system CPU when these operations occur but if I execute
all the program logic with the single exception of the setElementAt call, it
consumes only 3% of the CPU.  Is it reasonable that modifying one element of
a list once a second would consume so much CPU?  Also, the modification time
increases approximately linearly with list size.  If I make the list 1/2 the
size about 19% of the CPU is consumed.

It seems that if my list size grows, frequency of updates increases, or if I
operate more than a single list at a time (all of which are planned), I will
drag even a quite fast machine to its knees.  Are there more efficient
alternatives available?  The target machine is Windows, JRE 1.4.2_08 and the
development environment is Eclipse 3.1.

PL&F revalidates and repaints the entire list if any of it changes. Fortunately, there should only be so much on the screen that can be revalidate and repainted. However, the quoted times do seem excessive.

Tom Hawtin
--
Unemployed English Java programmer
http://jroller.com/page/tackline/
.

Relevant Pages

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