Here you can find the source of toUpperCase(String input)
public static String toUpperCase(String input)
//package com.java2s; /**/*from w w w .jav a 2s . c o m*/ * Copyright 2015 Jan Lolling jan.lolling@gmail.com * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ public class Main { /** * returns the upper case string, is null save * * {Category} StringUtil * * {param} string(input) input: String. * * {example} toUpperCase("abc") # "ABC" */ public static String toUpperCase(String input) { String s = getNullSaveStr(input); return s.toUpperCase(); } /** * Returns a empty not null String if input is null or equals "null", * otherwise returns input * * {Category} StringUtil * * {param} string(input) input: String. * * {example} getNullSaveStr(null) # "" */ public static String getNullSaveStr(String input) { if (input == null) { return ""; } else if ("null".equalsIgnoreCase(input)) { return ""; } else { return input; } } }