Java tutorial
//package com.java2s; //License from project: Apache License public class Main { public static int convertT9CharToIndex(char c) { if ((c >= '0') && (c <= '9')) { return c - '0'; } switch (c) { case '+': return 10; case ',': return 11; case '*': return 12; case '#': return 13; default: throw new IllegalArgumentException("INVALID T9 SEARCH CHARACTER"); } } }