1 /* 2 * ==================================================================== 3 * Licensed to the Apache Software Foundation (ASF) under one 4 * or more contributor license agreements. See the NOTICE file 5 * distributed with this work for additional information 6 * regarding copyright ownership. The ASF licenses this file 7 * to you under the Apache License, Version 2.0 (the 8 * "License"); you may not use this file except in compliance 9 * with the License. You may obtain a copy of the License at 10 * 11 * http://www.apache.org/licenses/LICENSE-2.0 12 * 13 * Unless required by applicable law or agreed to in writing, 14 * software distributed under the License is distributed on an 15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 16 * KIND, either express or implied. See the License for the 17 * specific language governing permissions and limitations 18 * under the License. 19 * ==================================================================== 20 * 21 * This software consists of voluntary contributions made by many 22 * individuals on behalf of the Apache Software Foundation. For more 23 * information on the Apache Software Foundation, please see 24 * <http://www.apache.org/>. 25 * 26 */ 27 28 package org.apache.hc.core5.util; 29 30 /** 31 * @since 4.3 32 */ 33 public final class TextUtils { 34 35 private TextUtils() { 36 // Do not allow utility class to be instantiated. 37 } 38 39 /** 40 * Returns true if the parameter is null or of zero length 41 */ 42 public static boolean isEmpty(final CharSequence s) { 43 if (s == null) { 44 return true; 45 } 46 return s.length() == 0; 47 } 48 49 /** 50 * Returns true if the parameter is null or contains only whitespace 51 */ 52 public static boolean isBlank(final CharSequence s) { 53 if (s == null) { 54 return true; 55 } 56 for (int i = 0; i < s.length(); i++) { 57 if (!Character.isWhitespace(s.charAt(i))) { 58 return false; 59 } 60 } 61 return true; 62 } 63 64 /** 65 * @since 4.4 66 */ 67 public static boolean containsBlanks(final CharSequence s) { 68 if (s == null) { 69 return false; 70 } 71 for (int i = 0; i < s.length(); i++) { 72 if (Character.isWhitespace(s.charAt(i))) { 73 return true; 74 } 75 } 76 return false; 77 } 78 79 /** 80 * Returns a hexadecimal string with lowercase letters, representing the 81 * values of the {@code bytes}. 82 * 83 * @param bytes whose hex string should be created 84 * @return hex string for the bytes 85 * 86 * @since 5.0 87 */ 88 public static String toHexString(final byte[] bytes) { 89 if (bytes == null) { 90 return null; 91 } 92 final StringBuffer buffer = new StringBuffer(); 93 for (int i = 0; i < bytes.length; i++) { 94 final int unsignedB = bytes[i] & 0xff; 95 if (unsignedB < 16) { 96 buffer.append('0'); 97 } 98 buffer.append(Integer.toHexString(unsignedB)); 99 } 100 return buffer.toString(); 101 } 102 103 }