| /* |
| * 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. |
| */ |
| package org.apache.commons.lang3; |
| |
| /** |
| * <p>Operations on char primitives and Character objects.</p> |
| * |
| * <p>This class tries to handle {@code null} input gracefully. |
| * An exception will not be thrown for a {@code null} input. |
| * Each method documents its behavior in more detail.</p> |
| * |
| * <p>#ThreadSafe#</p> |
| * @since 2.1 |
| */ |
| public class CharUtils { |
| |
| private static final String[] CHAR_STRING_ARRAY = new String[128]; |
| |
| private static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; |
| |
| /** |
| * Linefeed character LF ({@code '\n'}, Unicode 000a). |
| * |
| * @see <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.10.6">JLF: Escape Sequences |
| * for Character and String Literals</a> |
| * @since 2.2 |
| */ |
| public static final char LF = '\n'; |
| |
| /** |
| * Carriage return characterf CR ('\r', Unicode 000d). |
| * |
| * @see <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-3.html#jls-3.10.6">JLF: Escape Sequences |
| * for Character and String Literals</a> |
| * @since 2.2 |
| */ |
| public static final char CR = '\r'; |
| |
| /** |
| * {@code \u0000} null control character ('\0'), abbreviated NUL. |
| * |
| * @since 3.6 |
| */ |
| public static final char NUL = '\0'; |
| |
| static { |
| for (char c = 0; c < CHAR_STRING_ARRAY.length; c++) { |
| CHAR_STRING_ARRAY[c] = String.valueOf(c); |
| } |
| } |
| |
| /** |
| * <p>{@code CharUtils} instances should NOT be constructed in standard programming. |
| * Instead, the class should be used as {@code CharUtils.toString('c');}.</p> |
| * |
| * <p>This constructor is public to permit tools that require a JavaBean instance |
| * to operate.</p> |
| */ |
| public CharUtils() { |
| } |
| |
| /** |
| * <p>Converts the character to a Character.</p> |
| * |
| * <p>For ASCII 7 bit characters, this uses a cache that will return the |
| * same Character object each time.</p> |
| * |
| * <pre> |
| * CharUtils.toCharacterObject(' ') = ' ' |
| * CharUtils.toCharacterObject('A') = 'A' |
| * </pre> |
| * |
| * @deprecated Java 5 introduced {@link Character#valueOf(char)} which caches chars 0 through 127. |
| * @param ch the character to convert |
| * @return a Character of the specified character |
| */ |
| @Deprecated |
| public static Character toCharacterObject(final char ch) { |
| return Character.valueOf(ch); |
| } |
| |
| /** |
| * <p>Converts the String to a Character using the first character, returning |
| * null for empty Strings.</p> |
| * |
| * <p>For ASCII 7 bit characters, this uses a cache that will return the |
| * same Character object each time.</p> |
| * |
| * <pre> |
| * CharUtils.toCharacterObject(null) = null |
| * CharUtils.toCharacterObject("") = null |
| * CharUtils.toCharacterObject("A") = 'A' |
| * CharUtils.toCharacterObject("BA") = 'B' |
| * </pre> |
| * |
| * @param str the character to convert |
| * @return the Character value of the first letter of the String |
| */ |
| public static Character toCharacterObject(final String str) { |
| if (StringUtils.isEmpty(str)) { |
| return null; |
| } |
| return Character.valueOf(str.charAt(0)); |
| } |
| |
| /** |
| * <p>Converts the Character to a char throwing an exception for {@code null}.</p> |
| * |
| * <pre> |
| * CharUtils.toChar(' ') = ' ' |
| * CharUtils.toChar('A') = 'A' |
| * CharUtils.toChar(null) throws IllegalArgumentException |
| * </pre> |
| * |
| * @param ch the character to convert |
| * @return the char value of the Character |
| * @throws NullPointerException if the Character is null |
| */ |
| public static char toChar(final Character ch) { |
| Validate.notNull(ch, "ch"); |
| return ch.charValue(); |
| } |
| |
| /** |
| * <p>Converts the Character to a char handling {@code null}.</p> |
| * |
| * <pre> |
| * CharUtils.toChar(null, 'X') = 'X' |
| * CharUtils.toChar(' ', 'X') = ' ' |
| * CharUtils.toChar('A', 'X') = 'A' |
| * </pre> |
| * |
| * @param ch the character to convert |
| * @param defaultValue the value to use if the Character is null |
| * @return the char value of the Character or the default if null |
| */ |
| public static char toChar(final Character ch, final char defaultValue) { |
| if (ch == null) { |
| return defaultValue; |
| } |
| return ch.charValue(); |
| } |
| |
| /** |
| * <p>Converts the String to a char using the first character, throwing |
| * an exception on empty Strings.</p> |
| * |
| * <pre> |
| * CharUtils.toChar("A") = 'A' |
| * CharUtils.toChar("BA") = 'B' |
| * CharUtils.toChar(null) throws IllegalArgumentException |
| * CharUtils.toChar("") throws IllegalArgumentException |
| * </pre> |
| * |
| * @param str the character to convert |
| * @return the char value of the first letter of the String |
| * @throws NullPointerException if the string is null |
| * @throws IllegalArgumentException if the String is empty |
| */ |
| public static char toChar(final String str) { |
| Validate.notEmpty(str, "The String must not be empty"); |
| return str.charAt(0); |
| } |
| |
| /** |
| * <p>Converts the String to a char using the first character, defaulting |
| * the value on empty Strings.</p> |
| * |
| * <pre> |
| * CharUtils.toChar(null, 'X') = 'X' |
| * CharUtils.toChar("", 'X') = 'X' |
| * CharUtils.toChar("A", 'X') = 'A' |
| * CharUtils.toChar("BA", 'X') = 'B' |
| * </pre> |
| * |
| * @param str the character to convert |
| * @param defaultValue the value to use if the Character is null |
| * @return the char value of the first letter of the String or the default if null |
| */ |
| public static char toChar(final String str, final char defaultValue) { |
| if (StringUtils.isEmpty(str)) { |
| return defaultValue; |
| } |
| return str.charAt(0); |
| } |
| |
| /** |
| * <p>Converts the character to the Integer it represents, throwing an |
| * exception if the character is not numeric.</p> |
| * |
| * <p>This method converts the char '1' to the int 1 and so on.</p> |
| * |
| * <pre> |
| * CharUtils.toIntValue('3') = 3 |
| * CharUtils.toIntValue('A') throws IllegalArgumentException |
| * </pre> |
| * |
| * @param ch the character to convert |
| * @return the int value of the character |
| * @throws IllegalArgumentException if the character is not ASCII numeric |
| */ |
| public static int toIntValue(final char ch) { |
| if (!isAsciiNumeric(ch)) { |
| throw new IllegalArgumentException("The character " + ch + " is not in the range '0' - '9'"); |
| } |
| return ch - 48; |
| } |
| |
| /** |
| * <p>Converts the character to the Integer it represents, throwing an |
| * exception if the character is not numeric.</p> |
| * |
| * <p>This method converts the char '1' to the int 1 and so on.</p> |
| * |
| * <pre> |
| * CharUtils.toIntValue('3', -1) = 3 |
| * CharUtils.toIntValue('A', -1) = -1 |
| * </pre> |
| * |
| * @param ch the character to convert |
| * @param defaultValue the default value to use if the character is not numeric |
| * @return the int value of the character |
| */ |
| public static int toIntValue(final char ch, final int defaultValue) { |
| if (!isAsciiNumeric(ch)) { |
| return defaultValue; |
| } |
| return ch - 48; |
| } |
| |
| /** |
| * <p>Converts the character to the Integer it represents, throwing an |
| * exception if the character is not numeric.</p> |
| * |
| * <p>This method converts the char '1' to the int 1 and so on.</p> |
| * |
| * <pre> |
| * CharUtils.toIntValue('3') = 3 |
| * CharUtils.toIntValue(null) throws IllegalArgumentException |
| * CharUtils.toIntValue('A') throws IllegalArgumentException |
| * </pre> |
| * |
| * @param ch the character to convert, not null |
| * @return the int value of the character |
| * @throws NullPointerException if the Character is null |
| * @throws IllegalArgumentException if the Character is not ASCII numeric |
| */ |
| public static int toIntValue(final Character ch) { |
| Validate.notNull(ch, "ch"); |
| return toIntValue(ch.charValue()); |
| } |
| |
| /** |
| * <p>Converts the character to the Integer it represents, throwing an |
| * exception if the character is not numeric.</p> |
| * |
| * <p>This method converts the char '1' to the int 1 and so on.</p> |
| * |
| * <pre> |
| * CharUtils.toIntValue(null, -1) = -1 |
| * CharUtils.toIntValue('3', -1) = 3 |
| * CharUtils.toIntValue('A', -1) = -1 |
| * </pre> |
| * |
| * @param ch the character to convert |
| * @param defaultValue the default value to use if the character is not numeric |
| * @return the int value of the character |
| */ |
| public static int toIntValue(final Character ch, final int defaultValue) { |
| if (ch == null) { |
| return defaultValue; |
| } |
| return toIntValue(ch.charValue(), defaultValue); |
| } |
| |
| /** |
| * <p>Converts the character to a String that contains the one character.</p> |
| * |
| * <p>For ASCII 7 bit characters, this uses a cache that will return the |
| * same String object each time.</p> |
| * |
| * <pre> |
| * CharUtils.toString(' ') = " " |
| * CharUtils.toString('A') = "A" |
| * </pre> |
| * |
| * @param ch the character to convert |
| * @return a String containing the one specified character |
| */ |
| public static String toString(final char ch) { |
| if (ch < 128) { |
| return CHAR_STRING_ARRAY[ch]; |
| } |
| return new String(new char[] {ch}); |
| } |
| |
| /** |
| * <p>Converts the character to a String that contains the one character.</p> |
| * |
| * <p>For ASCII 7 bit characters, this uses a cache that will return the |
| * same String object each time.</p> |
| * |
| * <p>If {@code null} is passed in, {@code null} will be returned.</p> |
| * |
| * <pre> |
| * CharUtils.toString(null) = null |
| * CharUtils.toString(' ') = " " |
| * CharUtils.toString('A') = "A" |
| * </pre> |
| * |
| * @param ch the character to convert |
| * @return a String containing the one specified character |
| */ |
| public static String toString(final Character ch) { |
| if (ch == null) { |
| return null; |
| } |
| return toString(ch.charValue()); |
| } |
| |
| //-------------------------------------------------------------------------- |
| /** |
| * <p>Converts the string to the Unicode format '\u0020'.</p> |
| * |
| * <p>This format is the Java source code format.</p> |
| * |
| * <pre> |
| * CharUtils.unicodeEscaped(' ') = "\u0020" |
| * CharUtils.unicodeEscaped('A') = "\u0041" |
| * </pre> |
| * |
| * @param ch the character to convert |
| * @return the escaped Unicode string |
| */ |
| public static String unicodeEscaped(final char ch) { |
| return "\\u" + |
| HEX_DIGITS[(ch >> 12) & 15] + |
| HEX_DIGITS[(ch >> 8) & 15] + |
| HEX_DIGITS[(ch >> 4) & 15] + |
| HEX_DIGITS[(ch) & 15]; |
| } |
| |
| /** |
| * <p>Converts the string to the Unicode format '\u0020'.</p> |
| * |
| * <p>This format is the Java source code format.</p> |
| * |
| * <p>If {@code null} is passed in, {@code null} will be returned.</p> |
| * |
| * <pre> |
| * CharUtils.unicodeEscaped(null) = null |
| * CharUtils.unicodeEscaped(' ') = "\u0020" |
| * CharUtils.unicodeEscaped('A') = "\u0041" |
| * </pre> |
| * |
| * @param ch the character to convert, may be null |
| * @return the escaped Unicode string, null if null input |
| */ |
| public static String unicodeEscaped(final Character ch) { |
| if (ch == null) { |
| return null; |
| } |
| return unicodeEscaped(ch.charValue()); |
| } |
| |
| //-------------------------------------------------------------------------- |
| /** |
| * <p>Checks whether the character is ASCII 7 bit.</p> |
| * |
| * <pre> |
| * CharUtils.isAscii('a') = true |
| * CharUtils.isAscii('A') = true |
| * CharUtils.isAscii('3') = true |
| * CharUtils.isAscii('-') = true |
| * CharUtils.isAscii('\n') = true |
| * CharUtils.isAscii('©') = false |
| * </pre> |
| * |
| * @param ch the character to check |
| * @return true if less than 128 |
| */ |
| public static boolean isAscii(final char ch) { |
| return ch < 128; |
| } |
| |
| /** |
| * <p>Checks whether the character is ASCII 7 bit printable.</p> |
| * |
| * <pre> |
| * CharUtils.isAsciiPrintable('a') = true |
| * CharUtils.isAsciiPrintable('A') = true |
| * CharUtils.isAsciiPrintable('3') = true |
| * CharUtils.isAsciiPrintable('-') = true |
| * CharUtils.isAsciiPrintable('\n') = false |
| * CharUtils.isAsciiPrintable('©') = false |
| * </pre> |
| * |
| * @param ch the character to check |
| * @return true if between 32 and 126 inclusive |
| */ |
| public static boolean isAsciiPrintable(final char ch) { |
| return ch >= 32 && ch < 127; |
| } |
| |
| /** |
| * <p>Checks whether the character is ASCII 7 bit control.</p> |
| * |
| * <pre> |
| * CharUtils.isAsciiControl('a') = false |
| * CharUtils.isAsciiControl('A') = false |
| * CharUtils.isAsciiControl('3') = false |
| * CharUtils.isAsciiControl('-') = false |
| * CharUtils.isAsciiControl('\n') = true |
| * CharUtils.isAsciiControl('©') = false |
| * </pre> |
| * |
| * @param ch the character to check |
| * @return true if less than 32 or equals 127 |
| */ |
| public static boolean isAsciiControl(final char ch) { |
| return ch < 32 || ch == 127; |
| } |
| |
| /** |
| * <p>Checks whether the character is ASCII 7 bit alphabetic.</p> |
| * |
| * <pre> |
| * CharUtils.isAsciiAlpha('a') = true |
| * CharUtils.isAsciiAlpha('A') = true |
| * CharUtils.isAsciiAlpha('3') = false |
| * CharUtils.isAsciiAlpha('-') = false |
| * CharUtils.isAsciiAlpha('\n') = false |
| * CharUtils.isAsciiAlpha('©') = false |
| * </pre> |
| * |
| * @param ch the character to check |
| * @return true if between 65 and 90 or 97 and 122 inclusive |
| */ |
| public static boolean isAsciiAlpha(final char ch) { |
| return isAsciiAlphaUpper(ch) || isAsciiAlphaLower(ch); |
| } |
| |
| /** |
| * <p>Checks whether the character is ASCII 7 bit alphabetic upper case.</p> |
| * |
| * <pre> |
| * CharUtils.isAsciiAlphaUpper('a') = false |
| * CharUtils.isAsciiAlphaUpper('A') = true |
| * CharUtils.isAsciiAlphaUpper('3') = false |
| * CharUtils.isAsciiAlphaUpper('-') = false |
| * CharUtils.isAsciiAlphaUpper('\n') = false |
| * CharUtils.isAsciiAlphaUpper('©') = false |
| * </pre> |
| * |
| * @param ch the character to check |
| * @return true if between 65 and 90 inclusive |
| */ |
| public static boolean isAsciiAlphaUpper(final char ch) { |
| return ch >= 'A' && ch <= 'Z'; |
| } |
| |
| /** |
| * <p>Checks whether the character is ASCII 7 bit alphabetic lower case.</p> |
| * |
| * <pre> |
| * CharUtils.isAsciiAlphaLower('a') = true |
| * CharUtils.isAsciiAlphaLower('A') = false |
| * CharUtils.isAsciiAlphaLower('3') = false |
| * CharUtils.isAsciiAlphaLower('-') = false |
| * CharUtils.isAsciiAlphaLower('\n') = false |
| * CharUtils.isAsciiAlphaLower('©') = false |
| * </pre> |
| * |
| * @param ch the character to check |
| * @return true if between 97 and 122 inclusive |
| */ |
| public static boolean isAsciiAlphaLower(final char ch) { |
| return ch >= 'a' && ch <= 'z'; |
| } |
| |
| /** |
| * <p>Checks whether the character is ASCII 7 bit numeric.</p> |
| * |
| * <pre> |
| * CharUtils.isAsciiNumeric('a') = false |
| * CharUtils.isAsciiNumeric('A') = false |
| * CharUtils.isAsciiNumeric('3') = true |
| * CharUtils.isAsciiNumeric('-') = false |
| * CharUtils.isAsciiNumeric('\n') = false |
| * CharUtils.isAsciiNumeric('©') = false |
| * </pre> |
| * |
| * @param ch the character to check |
| * @return true if between 48 and 57 inclusive |
| */ |
| public static boolean isAsciiNumeric(final char ch) { |
| return ch >= '0' && ch <= '9'; |
| } |
| |
| /** |
| * <p>Checks whether the character is ASCII 7 bit numeric.</p> |
| * |
| * <pre> |
| * CharUtils.isAsciiAlphanumeric('a') = true |
| * CharUtils.isAsciiAlphanumeric('A') = true |
| * CharUtils.isAsciiAlphanumeric('3') = true |
| * CharUtils.isAsciiAlphanumeric('-') = false |
| * CharUtils.isAsciiAlphanumeric('\n') = false |
| * CharUtils.isAsciiAlphanumeric('©') = false |
| * </pre> |
| * |
| * @param ch the character to check |
| * @return true if between 48 and 57 or 65 and 90 or 97 and 122 inclusive |
| */ |
| public static boolean isAsciiAlphanumeric(final char ch) { |
| return isAsciiAlpha(ch) || isAsciiNumeric(ch); |
| } |
| |
| /** |
| * <p>Compares two {@code char} values numerically. This is the same functionality as provided in Java 7.</p> |
| * |
| * @param x the first {@code char} to compare |
| * @param y the second {@code char} to compare |
| * @return the value {@code 0} if {@code x == y}; |
| * a value less than {@code 0} if {@code x < y}; and |
| * a value greater than {@code 0} if {@code x > y} |
| * @since 3.4 |
| */ |
| public static int compare(final char x, final char y) { |
| return x-y; |
| } |
| } |
