package examples.pilib
import scala.concurrent.pilib._
/** Two-place buffer specification and implementation. */
object twoPlaceBuffer extends Application {
/**
* Specification.
*/
def Spec[A](in: Chan[A], out: Chan[A]) {
def B0: Unit = choice (
in * (x => B1(x))
)
def B1(x: A): Unit = choice (
out(x) * (B0),
in * (y => B2(x, y))
)
def B2(x: A, y: A): Unit = choice (
out(x) * (B1(y))
)
B0
}
/**
* Implementation using two one-place buffers.
*/
def Impl[A](in: Chan[A], out: Chan[A]) {
///- ... complete here ...
// one-place buffer
def OnePlaceBuffer[A](in: Chan[A], out: Chan[A]) {
def B0: Unit = choice ( in * (x => B1(x)) )
def B1(x: A): Unit = choice ( out(x) * (B0))
B0
}
val hidden = new Chan[A]
spawn < OnePlaceBuffer(in, hidden) | OnePlaceBuffer(hidden, out) >
///+
}
val random = new util.Random()
def Producer(n: Int, in: Chan[String]) {
Thread.sleep(random.nextInt(1000))
val msg = "" + n
choice (in(msg) * {})
Producer(n + 1, in)
}
def Consumer(out: Chan[String]) {
Thread.sleep(random.nextInt(1000))
choice (out * { msg => () })
Consumer(out)
}
val in = new Chan[String]
in.attach(s => println("put " + s))
val out = new Chan[String]
out.attach(s => println("get " + s))
//spawn < Producer(0, in) | Consumer(out) | Spec(in, out) >
spawn < Producer(0, in) | Consumer(out) | Impl(in, out) >
}