September 2017 Update

Task/Metered-concurrency/Go/metered-concurrency-3.go

@@ -1,56 +0,0 @@
-package main
-
-import (
-    "log"
-    "os"
-    "sync"
-    "time"
-)
-
-var fmt = log.New(os.Stdout, "", 0)
-
-func main() {
-    // three operations per task description
-    acquire := make(chan int)
-    release := make(chan int)
-    count := make(chan chan int)
-
-    // library analogy per WP article
-    go librarian(acquire, release, count, 10)
-    nStudents := 20
-    var studied sync.WaitGroup
-    studied.Add(nStudents)
-    for i := 0; i < nStudents; i++ {
-        go student(acquire, release, count, &studied)
-    }
-    // wait until all students have studied before terminating program
-    studied.Wait()
-}
-
-func librarian(a, r chan int, c chan chan int, count int) {
-    p := a // acquire operation is served or not depending on count
-    for {
-        select {
-        case <-p:       // acquire/p/wait operation
-            count--
-            if count == 0 {
-                p = nil
-            }
-        case <-r:       // release/v operation
-            count++
-            p = a
-        case cc := <-c: // count operation
-            cc <- count
-        }
-    }
-}
-
-func student(a, r chan int, c chan chan int, studied *sync.WaitGroup) {
-    cc := make(chan int)
-    a <- 0                      // acquire
-    c <- cc                     // request count
-    fmt.Printf("Room entered.  Count is %d.  Studying...\n", <-cc)
-    time.Sleep(2 * time.Second) // sleep per task description
-    r <- 0                      // release
-    studied.Done()              // signal done
-}