Merge pull request #4105 from hozlucas28/Solution-23-Go

#23 - Go

Author: Roswell468

Roadmap/23 - SINGLETON/go/hozlucas28.go

@@ -0,0 +1,184 @@
+package main
+
+import (
+	"fmt"
+	"sync"
+)
+
+/* -------------------------------------------------------------------------- */
+/*                                   CLASSES                                  */
+/* -------------------------------------------------------------------------- */
+
+/* --------------------------------- Counter -------------------------------- */
+
+type counter struct {
+	__count int
+}
+
+var counterMutex *sync.Mutex = &sync.Mutex{}
+
+var counterInstance *counter
+
+func Counter() *counter {
+	if counterInstance == nil {
+		counterMutex.Lock()
+		defer counterMutex.Unlock()
+
+		if counterInstance == nil {
+			counterInstance = &counter{}
+		}
+	}
+
+	return counterInstance
+}
+
+func (counter *counter) getCount() int {
+	return counter.__count
+}
+
+func (counter *counter) decrement() *counter {
+	counter.__count -= 1
+	return counter
+}
+
+func (counter *counter) increment() *counter {
+	counter.__count += 1
+	return counter
+}
+
+/* --------------------------------- Session -------------------------------- */
+
+type session struct {
+	__email    string
+	__id       string
+	__name     string
+	__userName string
+}
+
+var sessionMutex *sync.Mutex = &sync.Mutex{}
+
+var sessionInstance *session
+
+type SessionParams struct {
+	email    string
+	id       string
+	name     string
+	userName string
+}
+
+func Session(params SessionParams) *session {
+
+	if sessionInstance == nil {
+		sessionMutex.Lock()
+		defer sessionMutex.Unlock()
+
+		if sessionInstance == nil {
+			sessionInstance = &session{
+				__email:    params.email,
+				__id:       params.id,
+				__name:     params.name,
+				__userName: params.userName,
+			}
+		}
+	}
+
+	return sessionInstance
+}
+
+func (session *session) getEmail() string {
+	return session.__email
+}
+
+func (session *session) getId() string {
+	return session.__id
+}
+
+func (session *session) getName() string {
+	return session.__name
+}
+
+func (session *session) getUserName() string {
+	return session.__userName
+}
+
+func (session *session) setEmail(newEmail string) *session {
+	session.__email = newEmail
+	return session
+}
+
+func (session *session) setId(newId string) *session {
+	session.__id = newId
+	return session
+}
+
+func (session *session) setName(newName string) *session {
+	session.__name = newName
+	return session
+}
+
+func (session *session) setUserName(newUserName string) *session {
+	session.__userName = newUserName
+	return session
+}
+
+func (session *session) deleteData() *session {
+	session.__email = ""
+	session.__id = ""
+	session.__name = ""
+	session.__userName = ""
+
+	return session
+}
+
+/* -------------------------------------------------------------------------- */
+/*                                    MAIN                                    */
+/* -------------------------------------------------------------------------- */
+
+func main() {
+	/*
+		Singleton pattern...
+	*/
+
+	fmt.Println("Singleton pattern...")
+
+	var counter01 *counter = Counter()
+	var counter02 *counter = Counter()
+
+	fmt.Printf("\nAre `counter01` and `counter02` the same instance of `counter` class? %t\n", counter01 == counter02)
+
+	fmt.Println("\nMethod call of `counter01` instance...")
+
+	counter01.increment().increment().increment()
+	fmt.Println("\ncounter01.increment().increment().increment()")
+
+	fmt.Printf("\nCount attribute of `counter01` instance --> %d\n", counter01.getCount())
+
+	fmt.Println("\nMethod call of `counter02` instance...")
+
+	counter02.decrement()
+	fmt.Println("\ncounter02.decrement()")
+
+	fmt.Printf("\nCount attribute of `counter02` instance --> %d\n", counter02.getCount())
+
+	fmt.Println("\n# ---------------------------------------------------------------------------------- #")
+
+	/*
+		Additional challenge...
+	*/
+
+	fmt.Println("\nAdditional challenge...")
+
+	var userSession *session = Session(SessionParams{
+		email:    "[email protected]",
+		id:       "11U-287O-25ZK",
+		name:     "Mariano",
+		userName: "MarianoPro360",
+	})
+
+	fmt.Printf("\nUser session data: %s %s %s %s\n", userSession.getId(), userSession.getName(), userSession.getUserName(), userSession.getEmail())
+
+	userSession.deleteData()
+	fmt.Println("\nUser session data deleted!")
+
+	fmt.Printf("\nUser session data: %s %s %s %s", userSession.getId(), userSession.getName(), userSession.getUserName(), userSession.getEmail())
+}