Hi,
I think I found a minor problem. It appears with the error handling
of agents and actually is just a minor glitch in the output.
Consider the following session, copied from a terminal:
shell> java -cp clojure.jar clojure.main
Clojure 1.2.0-beta1
user=> (def agt1 (agent "One"))
#'user/agt1
user=> (defn upd-agt1 [current new-val]
(if (= new-val "fail")
(throw (Exception. "Update failed."))
(str "Update: " new-val)))
#'user/upd-agt1
user=> (error-mode agt1)
:fail
user=> (send agt1 upd-agt1 "fail")
#<ag...@21ed5459 FAILED: "One">
It creates an agent and causes an error in the update function. The
error mode of the agent is :fail and it silently fails when calling
the action. The failed status is visible from the printed output of
the agent in the last line. Further attempts to update the agent will
raise an exception.
Now for a second version see the following session, which started
fresh. It does the same thing as the first session, but it makes sure
that the thread-pool for the agents contains more threads, first.
shell> java -cp clojure.jar clojure.main
Clojure 1.2.0-beta1
;; this just creates some threads in the pool
user=> (def agt2 (agent {:count 0}))
#'user/agt2
user=> (defn agt2-action [state]
(println "In Thread" (.getName (Thread/currentThread)))
(if (< (:count state) 5)
(do (send agt2 agt2-action)
(assoc state :count (inc (:count state))))
state))
#'user/agt2-action
user=> (send agt2 agt2-action)
In Thread pool-1-thread-1
#<ag...@4c6504bc: In Thread pool-1-thread-2
In Thread pool-1-thread-3
{:countIn Thread pool-1-thread-4
1}>
In Thread pool-1-thread-4
user=> In Thread pool-1-thread-4
;; now the same as before...
user=> (def agt1 (agent "One"))
#'user/agt1
user=> (defn upd-agt1 [current new-val]
(if (= new-val "fail")
(throw (Exception. "Update failed."))
(str "Update: " new-val)))
#'user/upd-agt1
user=> (error-mode agt1)
:fail
user=> (send agt1 upd-agt1 "fail")
#<ag...@7f11bfbc: "One">
This time the output doesn't show the FAILED status of the agent.
I am by no means sure that this change in behavior is related to the
pool of threads. I found it by accident and could reproduce it
several times.
Kind regards,
Stefan
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