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 import java.util.Locale;
31
32 /**
33 * @since 4.3
34 */
35 public final class TextUtils {
36
37 private TextUtils() {
38 // Do not allow utility class to be instantiated.
39 }
40
41 /**
42 * Returns true if the parameter is null or of zero length
43 */
44 public static boolean isEmpty(final CharSequence s) {
45 return length(s) == 0;
46 }
47
48 /**
49 * <p>Checks if a CharSequence is empty (""), null or whitespace only.</p>
50 *
51 * <p>Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
52 *
53 * <pre>
54 * TextUtils.isBlank(null) = true
55 * TextUtils.isBlank("") = true
56 * TextUtils.isBlank(" ") = true
57 * TextUtils.isBlank("abg") = false
58 * TextUtils.isBlank(" abg ") = false
59 * </pre>
60 *
61 * @param s the CharSequence to check, may be null
62 * @return {@code true} if the CharSequence is null, empty or whitespace only
63 */
64 public static boolean isBlank(final CharSequence s) {
65 final int strLen = length(s);
66 if (strLen == 0) {
67 return true;
68 }
69 for (int i = 0; i < strLen; i++) {
70 if (!Character.isWhitespace(s.charAt(i))) {
71 return false;
72 }
73 }
74 return true;
75 }
76
77 /**
78 * Gets a CharSequence length or {@code 0} if the CharSequence is
79 * {@code null}.
80 *
81 * @param cs
82 * a CharSequence or {@code null}
83 * @return CharSequence length or {@code 0} if the CharSequence is
84 * {@code null}.
85 * @since 5.1
86 */
87 public static int length(final CharSequence cs) {
88 return cs == null ? 0 : cs.length();
89 }
90
91 /**
92 * @since 4.4
93 */
94 public static boolean containsBlanks(final CharSequence s) {
95 final int strLen = length(s);
96 if (strLen == 0) {
97 return false;
98 }
99 for (int i = 0; i < s.length(); i++) {
100 if (Character.isWhitespace(s.charAt(i))) {
101 return true;
102 }
103 }
104 return false;
105 }
106
107 /**
108 * Returns a hexadecimal string with lowercase letters, representing the
109 * values of the {@code bytes}.
110 *
111 * @param bytes whose hex string should be created
112 * @return hex string for the bytes
113 *
114 * @since 5.0
115 */
116 public static String toHexString(final byte[] bytes) {
117 if (bytes == null) {
118 return null;
119 }
120 final StringBuilder buffer = new StringBuilder();
121 for (int i = 0; i < bytes.length; i++) {
122 final int unsignedB = bytes[i] & 0xff;
123 if (unsignedB < 16) {
124 buffer.append('0');
125 }
126 buffer.append(Integer.toHexString(unsignedB));
127 }
128 return buffer.toString();
129 }
130
131 /**
132 * Returns lower case representation of the given string
133 * using {@link Locale#ROOT}.
134 *
135 * @since 5.2
136 */
137 public static String toLowerCase(final String s) {
138 if (s == null) {
139 return null;
140 }
141 return s.toLowerCase(Locale.ROOT);
142 }
143
144 }