A3: realy close to the finish line

go/TrafficLights/TrafficLight.go

@@ -2,47 +2,29 @@ package main
 
 import (
 	"fmt"
+	"runtime"
 )
 
-var printDebugMessages = false
-
-type CardinalDirection string
+//Definition CardinalDirection als enum
+type CardinalDirection int
 
 const (
-	north = CardinalDirection("North")
-	south = CardinalDirection("South")
-	east  = CardinalDirection("East")
-	west  = CardinalDirection("West")
+	north = iota
+	east
+	south
+	west
 )
 
-func nextDirection(currentDirection CardinalDirection) CardinalDirection {
-	switch currentDirection {
-	case north:
-		return east
-	case east:
-		return south
-	case south:
-		return west
-	case west:
-		return north
-	}
-	return north
+//definiert die nächste Richtung in der Reihenfolge north -> east -> south -> west -> north ...
+func nextDirection(direction CardinalDirection) CardinalDirection {
+	return (direction + 1) % (west + 1)
 }
 
-func oppositeDirection(currentDirection CardinalDirection) CardinalDirection {
-	switch currentDirection {
-	case north:
-		return south
-	case east:
-		return west
-	case south:
-		return north
-	case west:
-		return east
-	}
-	return north
+func (direction CardinalDirection) String() string {
+	return [...]string{"North", "East", "South", "West"}[direction]
 }
 
+//Definition Colour als enum
 type Colour int
 
 const (
@@ -51,40 +33,26 @@ const (
 	yellow
 )
 
-func (colour Colour) String() string {
-	switch colour {
-	case red:
-		return "Red"
-	case yellow:
-		return "Yellow"
-	case green:
-		return "Green"
-	default:
-		return "null"
-	}
-}
-
+//definiert nächste Farbe in der Reihenfolge red -> green -> yellow -> red ...
 func nextColour(colour Colour) Colour {
 	return (colour + 1) % (yellow + 1)
 }
 
-var northChannel = make(chan string)
-var southChannel = make(chan string)
-var eastChannel = make(chan string)
-var westChannel = make(chan string)
-
-func getChannel(direction CardinalDirection) chan string {
-	switch direction {
-	case north:
-		return northChannel
-	case south:
-		return northChannel
-	case east:
-		return eastChannel
-	case west:
-		return eastChannel
+func (colour Colour) String() string {
+	return [...]string{"Red", "Green", "Yellow"}[colour]
+}
+
+//Erstellung der Channel
+var northSouthChannel = make(chan string)
+var eastWestChannel = make(chan string)
+
+//Channel für die Achse erhalten, zu der direction gehört
+func getAxisChannel(direction CardinalDirection) chan string {
+	if direction == north || direction == south {
+		return northSouthChannel
+	} else {
+		return eastWestChannel
 	}
-	return nil
 }
 
 func main() {
@@ -111,41 +79,31 @@ func TrafficLight(direction CardinalDirection) {
 		if colour == red {
 			sync("wait", direction)
 			handover("changeDirection", direction)
+			runtime.Gosched()
 		}
-
-		sync("changeLight"+string(nextColour(colour)), direction)
+		sync("changeLight"+nextColour(colour).String(), direction)
 		colour = nextColour(colour)
 	}
 }
 
 func handover(message string, direction CardinalDirection) {
-	getChannel(nextDirection(direction)) <- message
+	getAxisChannel(nextDirection(direction)) <- message
 
 	select {
-	case msg := <-getChannel(direction):
-		debug(msg)
+	case <-getAxisChannel(direction):
 	}
+
 }
 
 func sync(message string, direction CardinalDirection) {
-	defer debug(string(direction) + " done with message " + message)
-
-	debug(string(direction) + " sync with message " + message)
 
 	select {
-	case getChannel(direction) <- message:
-	case msg := <-getChannel(direction):
-		debug(msg)
+	case getAxisChannel(direction) <- message:
+	case <-getAxisChannel(direction):
 	}
 
 }
 
 func show(direction CardinalDirection, colour Colour) {
-	fmt.Println(string(direction), " : ", colour.String())
-}
-
-func debug(message string) {
-	if printDebugMessages {
-		fmt.Println("Debug: " + message)
-	}
+	fmt.Println(direction.String(), " : ", colour.String())
 }