import java.util.List;

import net.minecraft.entity.player.EntityPlayerMP;
import net.minecraft.server.MinecraftServer;
import net.minecraft.util.ChatComponentText;
import net.minecraftforge.fml.common.Mod.EventHandler;

public class ServerTickEvent
{
	int intervalCounter = 0;
	//*20 for ticks, *60 for minutes
	int finalDuration = 1 * 20 * 60;

	@EventHandler
	public void onServerTick(ServerTickEvent event) {
		//20 ticks = 1 second - check the counter is finished.
		if(intervalCounter % finalDuration == 0) {
			intervalCounter = 1; //Reset counter
			List<EntityPlayerMP> playerList = MinecraftServer.getServer().getConfigurationManager().playerEntityList;

			for(EntityPlayerMP player : playerList) {
				player.addChatMessage(new ChatComponentText("Hello"));
			}
		} else {
			intervalCounter++;
		}
	}
}