added letter example with channel

concurrency/mastering_concurrency_in_go/ch1/iorem_ipsum.go

@@ -0,0 +1,35 @@
+package ch1
+
+// var initialString string
+// var finalString string
+// var stringLength int
+
+// func addToFinalStack(letterChannel chan string, wg *sync.WaitGroup) {
+// 	letter := <-letterChannel
+// 	finalString += letter
+// 	wg.Done()
+// }
+// func capitalize(letterChannel chan string, currentLetter string,
+// 	wg *sync.WaitGroup) {
+// 	thisLetter := strings.ToUpper(currentLetter)
+// 	wg.Done()
+// 	letterChannel <- thisLetter
+// }
+// func RunLorem() {
+// 	runtime.GOMAXPROCS(2)
+// 	var wg sync.WaitGroup
+// 	initialString = `Four score and seven years ago our fathers
+// brought forth on this continent, a new nation, conceived in
+// Liberty, and dedicated to the proposition that all men are
+// created equal.`
+// 	initialBytes := []byte(initialString)
+// 	var letterChannel chan string = make(chan string)
+// 	stringLength = len(initialBytes)
+// 	for i := 0; i < stringLength; i++ {
+// 		wg.Add(2)
+// 		go capitalize(letterChannel, string(initialBytes[i]), &wg)
+// 		go addToFinalStack(letterChannel, &wg)
+// 		wg.Wait()
+// 	}
+// 	fmt.Println(finalString)
+// }

concurrency/mastering_concurrency_in_go/ch1/letter_channel_example.go

@@ -0,0 +1,59 @@
+package ch1
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+)
+
+var initialString string
+var initialBytes []byte
+var stringLength int
+var finalString string
+var lettersProcessed int
+var applicationStatus bool
+var wg sync.WaitGroup
+
+func getLetters(gQ chan string) {
+	for i := range initialBytes {
+		gQ <- string(initialBytes[i])
+	}
+}
+func capitalizeLetters(gQ chan string, sQ chan string) {
+	for {
+		if lettersProcessed >= stringLength {
+			applicationStatus = false
+			break
+		}
+		select {
+		case letter := <-gQ:
+			capitalLetter := strings.ToUpper(letter)
+			finalString += capitalLetter
+			lettersProcessed++
+		}
+	}
+}
+func RunLetter() {
+	applicationStatus = true
+	getQueue := make(chan string)
+	stackQueue := make(chan string)
+	initialString = `Four score and seven years ago our fathers
+brought forth on this continent, a new nation, conceived in
+Liberty, and dedicated to the proposition that all men are
+created equal.`
+	initialBytes = []byte(initialString)
+	stringLength = len(initialString)
+	lettersProcessed = 0
+	fmt.Println("Let's start capitalizing")
+	go getLetters(getQueue)
+	capitalizeLetters(getQueue, stackQueue)
+	close(getQueue)
+	close(stackQueue)
+	for {
+		if applicationStatus == false {
+			fmt.Println("Done")
+			fmt.Println(finalString)
+			break
+		}
+	}
+}

concurrency/mastering_concurrency_in_go/main.go

@@ -3,5 +3,6 @@ package main
 import "github.com/jianhan/go-patterns/concurrency/mastering_concurrency_in_go/ch1"
 
 func main() {
-	ch1.Run()
+	// ch1.Run()
+	ch1.RunLetter()
 }

concurrency/select_block/main.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"time"
+
+	"github.com/davecgh/go-spew/spew"
+)
+
+func main() {
+	a := make(chan string)
+	go func() {
+		time.Sleep(time.Second * 2)
+		test := "string"
+		a <- test
+	}()
+
+	select {
+	case t := <-a:
+		spew.Dump(t)
+
+	}
+
+}