How to count number of notification and display single icon in Android?

I have multiple Android notification, but when I send a message from my web server, the android device creates a new notification icon on status bar. I want to count the number of unread notification, display it on statusbar with single icon, and when a notification is read, the notification has to change the number of unread notification count. How can I do it? It's look like "3 Others" in this image: Notification Icon