[Bug 62453] Tomcat tries to resolve uninitialized tag attributes in EL as java class names and this behavior causes performance problems.

[bu...@apache.org]

https://bz.apache.org/bugzilla/show_bug.cgi?id=62453

Mark Thomas <ma...@apache.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 OS|                            |All

--- Comment #1 from Mark Thomas <ma...@apache.org> ---
When Tomcat parses "baz.toString()" Tomcat has no way to determine if "baz" is
a class name and "toString" is the name of a static method or if "baz" is an
attribute and "toString" is an instance method. Tomcat has to do the class
lookup to find out.

The optimisation that was implemented in bug 57583 does not apply in this case.

In this simple case removing the "toString()" calls would improve performance
(it would allow the optimisation from bug 57583 to work) as there is an
implicit toString() in the EL evaluation.

In a more complex case the only way for an application to ensure it avoids the
expensive lookup is to use an explicit scope with the attributes. i.e.:

<div>foo:  ${pageScope.foo.toString()}</div>

etc.

Generally, explicitly stating the scope is the best approach. It allows faster
execution and does not depend on any container specific optimisation.

I've been taking a look at the code to see if there is anything further that
can be done in terms of optimisation. There are additional special cases we
could handle in a similar manner to bug 57583 but every special case adds
complexity and maintenance overhead. I'm not sure at this point if the
additional benefits are worth the cost. I need to run a few tests.

-- 
You are receiving this mail because:
You are the assignee for the bug.
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
For additional commands, e-mail: dev-help@tomcat.apache.org