Hi, people
I have created a quite large framework for business applications in
Lua, and we are now addressing the stress tests in order to improve the
performance.
Since I have created a lot of somewhat sophisticated tables to
represent fields in a Business Entity, I am having a little problem
duplicating some of those fields in instantiation. My field is a table
full of functions and attributes, and I have to copy a lot of things
from the 'fieldClass' table to a new 'fieldInstance' table to create
every field in an Entity - and that´s quite expensive.
I am begining to redesign it now (thinking of using metatables), and I
would like to know if there is any proven idiom for this kind of stuff
in lua.
Here´s what I am thinking:
I´ll separate the field class table in two inner tables: one for
attributes and one for methods. The attributes one I will copy (no help
there). The methods one I will replace in the instance with a metatable
that redirects to the class table' methods table whenever a method is
called.
The code will look like this:
local fieldClass = {
['#methods'] = {
get = function(Self)
return Self.value
end,
set = function(Self,value)
Self.value = value
end,
teste = function( Self, x, y )
return Self.msg .. tostring(x) .. tostring(y)
end,
-- some methods to fill some slack
a = function() print('') end,
b = function() print('') end,
c = function() print('') end,
d = function() print('') end,
e = function() print('') end,
f = function() print('') end,
g = function() print('') end,
h = function() print('') end,
i = function() print('') end,
j = function() print('') end,
},
-- attributes must stay flat
value = '',
type = '',
form = '',
mask = '',
height = '',
weight = '',
food = '',
color = '',
bla = '',
blabla = '',
msg = 'New Message'
}
-- metatable to locate methods
__defaultFieldMetaTable = {
__index = function(tabela, nome)
if(not rawget(tabela, nome)) then
if(not rawget( rawget(tabela, '#methods'), nome
) ) then
return nil;
else
local methodTable = rawget(tabela, '#methods')
local theMethod = rawget(methodTable, nome)
return function(...)
return theMethod(tabela, ...)
end
end
else
return rawget(tabela, nome);
end
end,
}
setmetatable( fieldClass, __defaultFieldMetaTable )
-- my clone function
clone = function(aTable)
local newTable = {}
for _,v in pairs(aTable) do
newTable[_] = aTable[_]
end
setmetatable( newTable, getmetatable(aTable) )
return newTable
end
-- measuring time
cloneTime = 0
new = function()
local newEntity = {}
for i=0, 50 do
local t = os.clock()
newEntity['field' .. i] = clone(fieldClass)
cloneTime = cloneTime + (os.clock() - t)
newEntity['field' .. i].set(i)
end
return newEntity
end
-- testing...
allEntities = {}
t = os.clock()
for i=0, 4000 do
table.insert(allEntities, new())
end
print("total: " .. os.clock() - t)
print("clone time: " .. cloneTime)
My problem being: Performance still sucks.
My question: is there anything I could still do in Lua or shall I begin
to prepare to move into userdata?
Thanks in advance,
Luís Eduardo Jason Santos