A cheap way to run a compiled function (keeping with your "test"
function) in threadsafe manner:
Script script = ...; // you obtain this from somewhere, cache it, etc.
It's shared
Context cx = Context.enter(); // Consider using ContextFactory.call()
instead
ScriptableObject scope = cx.initStandardObjects();
script.exec(cx, scope);
Object retval = ScriptableObject.callMethod(cx, scope, "test", args);
Context.exit();
There will be one class generated for your "test" function (as you
compiled the script only once), so no permgen exhaustion -
script.exec() will create new instances of that single class.
You can also have a pre-created "standard" scope with
initStandardObjects() run in it, seal it (so it's read-only) and set
it as prototype of any per-request scopes, that way you can even avoid
javing to run initStandardObjects() on a per request basis:
// On system initalization:
Context cx = Context.enter();
ScriptableObject standardScope = cx.initStandardObjects();
... you can even add some further proprietary "standard" objects and
global functions here by executing a script into standardScope
standardScope.seal();
Context.exit();
// This is per request:
Script script = ...; // you obtain this from somewhere, cache it, etc.
It's shared
Context cx = Context.enter(); // Consider using ContextFactory.call()
instead
> ScriptableObject scope = cx.newObject(standardScope);
> scope.setPrototype(standardScope);
script.exec(cx, scope);
Object retval = ScriptableObject.callMethod(cx, scope, "test", args);
Context.exit();
Note lines marked with ">" have changed. This is as efficient as it
gets.
Attila.
--
home: http://www.szegedi.org
twitter: http://twitter.com/szegedi
weblog: http://constc.blogspot.com
On 2008.12.10., at 17:28, Johan Compagner wrote:
came pretty much to the same conclusion
I guess we just have to run in interpreted mode because the class
generations is really killing on the server for our customers
Some have hundreds if not thousands of functions (and those are per
session)
So we get perm mem heap problems
I am going to profile a bit what the cost is running it in
interpreted mode.
johan
On Wed, Dec 10, 2008 at 17:20, Attila Szegedi <[EMAIL PROTECTED]>
wrote:
On 2008.12.10., at 16:35, Johan Compagner wrote:
also all our code are standalone functions like
function test()
{
// code
}
if i compile that as a script and say exec() then nothing happens
because
it
doesnt exec the function but just the scripts (which doesnt do
anything)
It does. It creates a function object and binds it to the property
name
"test" within the scope.
besides that suddenly having arguments also is not possible for us
because
many of our customers use "arguments" we cant just change that. So
using a
Script instead of a Function is just not possible
I am currently investigating why it is that function object cant
just be
as
a script, why we really need to have suddenly a parent and
prototype scope
which a Script (which also can have the same function it it)
doesnt seem
to
need
Here's a distinction:
As the JS spec does not define a runtime representation for the
program, a
script is not a first-class JS object. It is Rhino's implementation-
specific
representation of a JS program. There's no way to access or
manipulate it
within the program itself.
A function, on the other hand, is a first-class object in
JavaScript. I.e.
it is a Scriptable, and it also has a prototype (the standard
Function
object, which is why you need to have a scope with standard objects
in it to
create a function). As such, function objects are bound to a scope,
scripts
are not. Function objects are really created when a program
executes a
function statement or a function expression; and as any other first-
class JS
object, function objects are mutable (sort of - you can add/remove
arbitrary
properties to them, but you can't modify their code).
johan
Attila.
--
home: http://www.szegedi.org
twitter: http://twitter.com/szegedi
weblog: http://constc.blogspot.com
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