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. */ /** * Operations on {@link java.lang.String} that are * <code>null</code> safe. * * @see java.lang.String * @author <a href="http://jakarta.apache.org/turbine/">Apache Jakarta Turbine</a> * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a> * @author Daniel L. Rall * @author <a href="mailto:gcoladonato@yahoo.com">Greg Coladonato</a> * @author <a href="mailto:ed@apache.org">Ed Korthof</a> * @author <a href="mailto:rand_mcneely@yahoo.com">Rand McNeely</a> * @author Stephen Colebourne * @author <a href="mailto:fredrik@westermarck.com">Fredrik Westermarck</a> * @author Holger Krauth * @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a> * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> * @author Arun Mammen Thomas * @author Gary Gregory * @author Phil Steitz * @author Al Chou * @author Michael Davey * @author Reuben Sivan * @author Chris Hyzer * @author Scott Johnson * @since 1.0 * @version $Id: StringUtils.java 635447 2008-03-10 06:27:09Z bayard $ */ public class Main { /** * * Checks if the String contains any character in the given set of characters. * * * * A <code>null</code> String will return <code>false</code>. A <code>null</code> search string will return * <code>false</code>. * * * <pre> * StringUtils.containsAny(null, *) = false * StringUtils.containsAny("", *) = false * StringUtils.containsAny(*, null) = false * StringUtils.containsAny(*, "") = false * StringUtils.containsAny("zzabyycdxx", "za") = true * StringUtils.containsAny("zzabyycdxx", "by") = true * StringUtils.containsAny("aba","z") = false * </pre> * * @param str * the String to check, may be null * @param searchChars * the chars to search for, may be null * @return the <code>true</code> if any of the chars are found, <code>false</code> if no match or null input * @since 2.4 */ public static boolean containsAny(String str, String searchChars) { if (searchChars == null) { return false; } return containsAny(str, searchChars.toCharArray()); } // ContainsAny //----------------------------------------------------------------------- /** * Checks if the String contains any character in the given * set of characters. * * A <code>null</code> String will return <code>false</code>. * A <code>null</code> or zero length search array will return <code>false</code>. * * <pre> * StringUtils.containsAny(null, *) = false * StringUtils.containsAny("", *) = false * StringUtils.containsAny(*, null) = false * StringUtils.containsAny(*, []) = false * StringUtils.containsAny("zzabyycdxx",['z','a']) = true * StringUtils.containsAny("zzabyycdxx",['b','y']) = true * StringUtils.containsAny("aba", ['z']) = false * </pre> * * @param str the String to check, may be null * @param searchChars the chars to search for, may be null * @return the <code>true</code> if any of the chars are found, * <code>false</code> if no match or null input * @since 2.4 */ public static boolean containsAny(String str, char[] searchChars) { if (str == null || str.length() == 0 || searchChars == null || searchChars.length == 0) { return false; } for (int i = 0; i < str.length(); i++) { char ch = str.charAt(i); for (int j = 0; j < searchChars.length; j++) { if (searchChars[j] == ch) { return true; } } } return false; } // Empty checks //----------------------------------------------------------------------- /** * Checks if a String is empty ("") or null. * * <pre> * StringUtils.isEmpty(null) = true * StringUtils.isEmpty("") = true * StringUtils.isEmpty(" ") = false * StringUtils.isEmpty("bob") = false * StringUtils.isEmpty(" bob ") = false * </pre> * * NOTE: This method changed in Lang version 2.0. * It no longer trims the String. * That functionality is available in isBlank(). * * @param str the String to check, may be null * @return <code>true</code> if the String is empty or null */ public static boolean isEmpty(String str) { return str == null || str.length() == 0; } }