Trying to detect when player left clicks - 1.8.9

[CyborgGamer21]

As the title says I'm trying to detect when the player left clicks. Is there a event that I can use? Does anyone know how to?

I currently have this line of code to do it but doesn't count each click, instead it counts how long you hold it down:

Minecraft.getMinecraft().gameSettings.keyBindAttack.isKeyDown()