module examples.Concurrent where
import System.Random
import Java.Net (URL)
import Control.Concurrent as C
main2 args = do
m <- newEmptyMVar
forkIO do
m.put 'x'
m.put 'y'
m.put 'z'
replicateM_ 3 do
c <- m.take
print "got: "
println c
example1 = do
forkIO (replicateM_ 100000 (putChar 'a'))
replicateM_ 100000 (putChar 'b')
example2 = do
s <- getLine
case s.long of
Right n -> forkIO (setReminder n) >> example2
Left _ -> println ("exiting ...")
setReminder :: Long -> IO ()
setReminder n = do
println ("Ok, I remind you in " ++ show n ++ " seconds")
Thread.sleep (1000L*n)
println (show n ++ " seconds is up!")
table = "table"
mainPhil _ = do
[fork1,fork2,fork3,fork4,fork5] <- mapM MVar.new [1..5]
forkIO (philosopher "Kant" fork5 fork1)
forkIO (philosopher "Locke" fork1 fork2)
forkIO (philosopher "Wittgenstein" fork2 fork3)
forkIO (philosopher "Nozick" fork3 fork4)
forkIO (philosopher "Mises" fork4 fork5)
return ()
philosopher :: String -> MVar Int -> MVar Int -> IO ()
philosopher me left right = do
g <- Random.newStdGen
let phil g = do
let (tT,g1) = Random.randomR (60L, 120L) g
(eT, g2) = Random.randomR (80L, 160L) g1
thinkTime = 300L * tT
eatTime = 300L * eT
println(me ++ " is going to the dining room and takes his seat.")
fl <- left.take
println (me ++ " takes up left fork (" ++ show fl ++ ")")
rFork <- right.poll
case rFork of
Just fr -> do
println (me ++ " takes up right fork. (" ++ show fr ++ ")")
println (me ++ " is going to eat for " ++ show eatTime ++ "ms")
Thread.sleep eatTime
println (me ++ " finished eating.")
right.put fr
println (me ++ " took down right fork.")
left.put fl
println (me ++ " took down left fork.")
table.notifyAll
println(me ++ " is going to think for " ++ show thinkTime ++ "ms.")
Thread.sleep thinkTime
phil g2
Nothing -> do
println (me ++ " finds right fork is already in use.")
left.put fl
println (me ++ " took down left fork.")
table.notifyAll
println (me ++ " is going to the bar to await notifications from table.")
table.wait
println (me ++ " got notice that something changed at the table.")
phil g2
inter :: InterruptedException -> IO ()
inter _ = return ()
phil g `catch` inter
getURL xx = do
url <- URL.new xx
con <- url.openConnection
con.connect
is <- con.getInputStream
typ <- con.getContentType
-- stderr.println ("content-type is " ++ show typ)
ir <- InputStreamReader.new is (fromMaybe "UTF-8" (charset typ))
`catch` unsupportedEncoding is
br <- BufferedReader.new ir
br.getLines
where
unsupportedEncoding :: InputStream -> UnsupportedEncodingException -> IO InputStreamReader
unsupportedEncoding is x = do
stderr.println x.catched
InputStreamReader.new is "UTF-8"
charset ctyp = do
typ <- ctyp
case typ of
m~´charset=(\S+)´ -> m.group 1
_ -> Nothing
type SomeException = Throwable
main ["dining"] = mainPhil []
main _ = do
m1 <- MVar.newEmpty
m2 <- MVar.newEmpty
m3 <- MVar.newEmpty
forkIO do
r <- (catchAll . getURL) "http://www.wikipedia.org/wiki/Haskell"
m1.put r
forkIO do
r <- (catchAll . getURL) "htto://www.wikipedia.org/wiki/Java"
m2.put r
forkIO do
r <- (catchAll . getURL) "http://www.wikipedia.org/wiki/Frege"
m3.put r
r1 <- m1.take
r2 <- m2.take
r3 <- m3.take
println (result r1, result r2, result r3)
-- case r3 of
-- Right ss -> mapM_ putStrLn ss
-- Left _ -> return ()
where
result :: (SomeException|[String]) -> (String|Int)
result (Left x) = Left x.getClass.getName
result (Right y) = (Right . sum . map length) y
-- mapM_ putStrLn r2