in java please quickly

public int queueSize(String name) Counts how many customers are in front of the customer with that name. Returns the count. public Customer MinItems() Returns the Customer with the minimum total items. public double average() Calculates the average of the total items in the queue and returns its value. public int queueSize(String name) { //your code goes here } public Customer MinItems() { //your code goes here } public double average(). { //your code goes here }