For
those of you still following my weblog you all may remember that I had set
Inst.Ant asided for a while while I pondered two problems, transactions and
dynamic properties. I beleive I have solutions for both, but it may be a
wile before I get to playing with them... First on the
issue of dynaimc properties, Costin has been a busy little bee over the holiday
break, and has ported
his changes relating to the dynamic properties support from his
Embed proposal to the main ant line for 1.6. This means an end to evil hacks
a d a more sensible solution to the ant call and properties problems. It
may be a while before I get code written to exploit it, but as it is I need
to wait a bit for PropertyHelper and friends to harden just a little. And
then Ant 1.6 need so ship a FCS, which makes me shipping anything other than
alpha quality code before that kinda useless. To paraphrase the greate M.Python
"Inst.Ant's not dead (yet)." Now about Transactions, how
will I handle things throwing strange exceptions durring their executions
(including ant build failure tasks)? What I plan to do is wrap all of the
<do> targets into a try {} catch (Throwable t) {} block. It's
a pretty wide scope but I want to catch errors too like OutOfMemory. I will
then set an ant property holding the exception and set the execution order
to undo. If the steps taken depend on failure or canceling or undoing then
what that should be done on an error one can set the if= and unless= attributes
to check for that standard property. The same will be done for cancel and
(likely) normal forward back execution. If an error occurs in an undo the
error will be re set, so there is the possibility of both a cancel and error
flag being raised So how does that affect transactions?
It gives some greater control to the author to undo actions if stuff should
fail, such as out of memory errors. While the granularity isn't directly
to the level of individual task in the do/undo that can be fixed by the author
splitting the do tasks to as many mutliples as are needed, to the level of
one per do if that level of granularity is needed. And
in the interest of full disclosure, don't expect new code for a couple of
weeks, at least. Family stuff and paintball is coming up, although I believe
I have saciated my tase for NeverWinter Nights for a while longer. |
