package com.towel.collections.aggr; public class FuncAvg implements AggregateFunc<Number>{ private Number x; private int total; @Override public void update(Number obj) { x = new Double(x.doubleValue() + obj.doubleValue()); total++; } @Override public Number getResult() { return x.doubleValue() / total; } @Override public void init() { x = new Double(0); total = 0; } }