Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 { /** * <p>Checks if the String contains only unicode letters, digits * or space (<code>' '</code>).</p> * * <p><code>null</code> will return <code>false</code>. * An empty String ("") will return <code>true</code>.</p> * * <pre> * StringUtils.isAlphanumeric(null) = false * StringUtils.isAlphanumeric("") = true * StringUtils.isAlphanumeric(" ") = true * StringUtils.isAlphanumeric("abc") = true * StringUtils.isAlphanumeric("ab c") = true * StringUtils.isAlphanumeric("ab2c") = true * StringUtils.isAlphanumeric("ab-c") = false * </pre> * * @param str the String to check, may be null * @return <code>true</code> if only contains letters, digits or space, * and is non-null */ public static boolean isAlphanumericSpace(String str) { if (str == null) { return false; } int sz = str.length(); for (int i = 0; i < sz; i++) { if ((Character.isLetterOrDigit(str.charAt(i)) == false) && (str.charAt(i) != ' ')) { return false; } } return true; } }