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/*
 * 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 net.hasor.utils;
/**
 * 

Operations on char primitives and Character objects.

* *

This class tries to handle null input gracefully. * An exception will not be thrown for a null input. * Each method documents its behaviour in more detail.

* *

#ThreadSafe#

* @author Apache Software Foundation * @since 2.1 * @version $Id: CharUtils.java 1056988 2011-01-09 17:58:53Z niallp $ */ public class CharUtils { private static final String CHAR_STRING = // "\u0000\u0001\u0002\u0003\u0004\u0005\u0006\u0007" +// "\b\t\n\u000b\f\r\u000e\u000f" + // "\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017" + // "\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f" +// "\u0020\u0021\"\u0023\u0024\u0025\u0026\u0027" + // "\u0028\u0029\u002a\u002b\u002c\u002d\u002e\u002f" + // "\u0030\u0031\u0032\u0033\u0034\u0035\u0036\u0037" + // "\u0038\u0039\u003a\u003b\u003c\u003d\u003e\u003f" + // "\u0040\u0041\u0042\u0043\u0044\u0045\u0046\u0047" + // "\u0048\u0049\u004a\u004b\u004c\u004d\u004e\u004f" + // "\u0050\u0051\u0052\u0053\u0054\u0055\u0056\u0057" +// "\u0058\u0059\u005a\u005b\\\u005d\u005e\u005f" + // "\u0060\u0061\u0062\u0063\u0064\u0065\u0066\u0067" +// "\u0068\u0069\u006a\u006b\u006c\u006d\u006e\u006f" +// "\u0070\u0071\u0072\u0073\u0074\u0075\u0076\u0077" +// "\u0078\u0079\u007a\u007b\u007c\u007d\u007e\u007f"; private static final String[] CHAR_STRING_ARRAY = new String[128]; private static final Character[] CHAR_ARRAY = new Character[128]; /** * linefeed LF ('\n'). * * @see JLF: Escape Sequences * for Character and String Literals * @since 2.2 */ public static final char LF = '\n'; /** * carriage return CR ('\r'). * * @see JLF: Escape Sequences * for Character and String Literals * @since 2.2 */ public static final char CR = '\r'; static { for (int i = 127; i >= 0; i--) { CharUtils.CHAR_STRING_ARRAY[i] = CharUtils.CHAR_STRING.substring(i, i + 1); CharUtils.CHAR_ARRAY[i] = new Character((char) i); } } /** *

CharUtils instances should NOT be constructed in standard programming. * Instead, the class should be used as CharUtils.toString('c');.

* *

This constructor i public to permit tools that require a JavaBean instance * to operate.

*/ public CharUtils() { super(); } //----------------------------------------------------------------------- /** *

Converts the character to a Character.

* *

For ASCII 7 bit characters, this uses a cache that will return the * same Character object each time.

* *
     *   CharUtils.toCharacterObject(' ')  = ' '
     *   CharUtils.toCharacterObject('A')  = 'A'
     * 
* * @param ch the character to convert * @return a Character of the specified character */ public static Character toCharacterObject(final char ch) { if (ch < CharUtils.CHAR_ARRAY.length) { return CharUtils.CHAR_ARRAY[ch]; } return new Character(ch); } /** *

Converts the String to a Character using the first character, returning * null for empty Strings.

* *

For ASCII 7 bit characters, this uses a cache that will return the * same Character object each time.

* *
     *   CharUtils.toCharacterObject(null) = null
     *   CharUtils.toCharacterObject("")   = null
     *   CharUtils.toCharacterObject("A")  = 'A'
     *   CharUtils.toCharacterObject("BA") = 'B'
     * 
* * @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 CharUtils.toCharacterObject(str.charAt(0)); } //----------------------------------------------------------------------- /** *

Converts the Character to a char throwing an exception for null.

* *
     *   CharUtils.toChar(null) = IllegalArgumentException
     *   CharUtils.toChar(' ')  = ' '
     *   CharUtils.toChar('A')  = 'A'
     * 
* * @param ch the character to convert * @return the char value of the Character * @throws IllegalArgumentException if the Character is null */ public static char toChar(final Character ch) { if (ch == null) { throw new IllegalArgumentException("The Character must not be null"); } return ch.charValue(); } /** *

Converts the Character to a char handling null.

* *
     *   CharUtils.toChar(null, 'X') = 'X'
     *   CharUtils.toChar(' ', 'X')  = ' '
     *   CharUtils.toChar('A', 'X')  = 'A'
     * 
* * @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(); } //----------------------------------------------------------------------- /** *

Converts the String to a char using the first character, throwing * an exception on empty Strings.

* *
     *   CharUtils.toChar(null) = IllegalArgumentException
     *   CharUtils.toChar("")   = IllegalArgumentException
     *   CharUtils.toChar("A")  = 'A'
     *   CharUtils.toChar("BA") = 'B'
     * 
* * @param str the character to convert * @return the char value of the first letter of the String * @throws IllegalArgumentException if the String is empty */ public static char toChar(final String str) { if (StringUtils.isEmpty(str)) { throw new IllegalArgumentException("The String must not be empty"); } return str.charAt(0); } /** *

Converts the String to a char using the first character, defaulting * the value on empty Strings.

* *
     *   CharUtils.toChar(null, 'X') = 'X'
     *   CharUtils.toChar("", 'X')   = 'X'
     *   CharUtils.toChar("A", 'X')  = 'A'
     *   CharUtils.toChar("BA", 'X') = 'B'
     * 
* * @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); } //----------------------------------------------------------------------- /** *

Converts the character to the Integer it represents, throwing an * exception if the character is not numeric.

* *

This method coverts the char '1' to the int 1 and so on.

* *
     *   CharUtils.toIntValue('3')  = 3
     *   CharUtils.toIntValue('A')  = IllegalArgumentException
     * 
* * @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 (CharUtils.isAsciiNumeric(ch) == false) { throw new IllegalArgumentException("The character " + ch + " is not in the range '0' - '9'"); } return ch - 48; } /** *

Converts the character to the Integer it represents, throwing an * exception if the character is not numeric.

* *

This method coverts the char '1' to the int 1 and so on.

* *
     *   CharUtils.toIntValue('3', -1)  = 3
     *   CharUtils.toIntValue('A', -1)  = -1
     * 
* * @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 (CharUtils.isAsciiNumeric(ch) == false) { return defaultValue; } return ch - 48; } /** *

Converts the character to the Integer it represents, throwing an * exception if the character is not numeric.

* *

This method coverts the char '1' to the int 1 and so on.

* *
     *   CharUtils.toIntValue(null) = IllegalArgumentException
     *   CharUtils.toIntValue('3')  = 3
     *   CharUtils.toIntValue('A')  = IllegalArgumentException
     * 
* * @param ch the character to convert, not null * @return the int value of the character * @throws IllegalArgumentException if the Character is not ASCII numeric or is null */ public static int toIntValue(final Character ch) { if (ch == null) { throw new IllegalArgumentException("The character must not be null"); } return CharUtils.toIntValue(ch.charValue()); } /** *

Converts the character to the Integer it represents, throwing an * exception if the character is not numeric.

* *

This method coverts the char '1' to the int 1 and so on.

* *
     *   CharUtils.toIntValue(null, -1) = -1
     *   CharUtils.toIntValue('3', -1)  = 3
     *   CharUtils.toIntValue('A', -1)  = -1
     * 
* * @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 CharUtils.toIntValue(ch.charValue(), defaultValue); } //----------------------------------------------------------------------- /** *

Converts the character to a String that contains the one character.

* *

For ASCII 7 bit characters, this uses a cache that will return the * same String object each time.

* *
     *   CharUtils.toString(' ')  = " "
     *   CharUtils.toString('A')  = "A"
     * 
* * @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 CharUtils.CHAR_STRING_ARRAY[ch]; } return new String(new char[] { ch }); } /** *

Converts the character to a String that contains the one character.

* *

For ASCII 7 bit characters, this uses a cache that will return the * same String object each time.

* *

If null is passed in, null will be returned.

* *
     *   CharUtils.toString(null) = null
     *   CharUtils.toString(' ')  = " "
     *   CharUtils.toString('A')  = "A"
     * 
* * @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 CharUtils.toString(ch.charValue()); } //-------------------------------------------------------------------------- /** *

Converts the string to the unicode format '\u0020'.

* *

This format is the Java source code format.

* *
     *   CharUtils.unicodeEscaped(' ') = "\u0020"
     *   CharUtils.unicodeEscaped('A') = "\u0041"
     * 
* * @param ch the character to convert * @return the escaped unicode string */ public static String unicodeEscaped(final char ch) { if (ch < 0x10) { return "\\u000" + Integer.toHexString(ch); } else if (ch < 0x100) { return "\\u00" + Integer.toHexString(ch); } else if (ch < 0x1000) { return "\\u0" + Integer.toHexString(ch); } return "\\u" + Integer.toHexString(ch); } /** *

Converts the string to the unicode format '\u0020'.

* *

This format is the Java source code format.

* *

If null is passed in, null will be returned.

* *
     *   CharUtils.unicodeEscaped(null) = null
     *   CharUtils.unicodeEscaped(' ')  = "\u0020"
     *   CharUtils.unicodeEscaped('A')  = "\u0041"
     * 
* * @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 CharUtils.unicodeEscaped(ch.charValue()); } //-------------------------------------------------------------------------- /** *

Checks whether the character is ASCII 7 bit.

* *
     *   CharUtils.isAscii('a')  = true
     *   CharUtils.isAscii('A')  = true
     *   CharUtils.isAscii('3')  = true
     *   CharUtils.isAscii('-')  = true
     *   CharUtils.isAscii('\n') = true
     *   CharUtils.isAscii('©') = false
     * 
* * @param ch the character to check * @return true if less than 128 */ public static boolean isAscii(final char ch) { return ch < 128; } /** *

Checks whether the character is ASCII 7 bit printable.

* *
     *   CharUtils.isAsciiPrintable('a')  = true
     *   CharUtils.isAsciiPrintable('A')  = true
     *   CharUtils.isAsciiPrintable('3')  = true
     *   CharUtils.isAsciiPrintable('-')  = true
     *   CharUtils.isAsciiPrintable('\n') = false
     *   CharUtils.isAsciiPrintable('©') = false
     * 
* * @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; } /** *

Checks whether the character is ASCII 7 bit control.

* *
     *   CharUtils.isAsciiControl('a')  = false
     *   CharUtils.isAsciiControl('A')  = false
     *   CharUtils.isAsciiControl('3')  = false
     *   CharUtils.isAsciiControl('-')  = false
     *   CharUtils.isAsciiControl('\n') = true
     *   CharUtils.isAsciiControl('©') = false
     * 
* * @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; } /** *

Checks whether the character is ASCII 7 bit alphabetic.

* *
     *   CharUtils.isAsciiAlpha('a')  = true
     *   CharUtils.isAsciiAlpha('A')  = true
     *   CharUtils.isAsciiAlpha('3')  = false
     *   CharUtils.isAsciiAlpha('-')  = false
     *   CharUtils.isAsciiAlpha('\n') = false
     *   CharUtils.isAsciiAlpha('©') = false
     * 
* * @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 ch >= 'A' && ch <= 'Z' || ch >= 'a' && ch <= 'z'; } /** *

Checks whether the character is ASCII 7 bit alphabetic upper case.

* *
     *   CharUtils.isAsciiAlphaUpper('a')  = false
     *   CharUtils.isAsciiAlphaUpper('A')  = true
     *   CharUtils.isAsciiAlphaUpper('3')  = false
     *   CharUtils.isAsciiAlphaUpper('-')  = false
     *   CharUtils.isAsciiAlphaUpper('\n') = false
     *   CharUtils.isAsciiAlphaUpper('©') = false
     * 
* * @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'; } /** *

Checks whether the character is ASCII 7 bit alphabetic lower case.

* *
     *   CharUtils.isAsciiAlphaLower('a')  = true
     *   CharUtils.isAsciiAlphaLower('A')  = false
     *   CharUtils.isAsciiAlphaLower('3')  = false
     *   CharUtils.isAsciiAlphaLower('-')  = false
     *   CharUtils.isAsciiAlphaLower('\n') = false
     *   CharUtils.isAsciiAlphaLower('©') = false
     * 
* * @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'; } /** *

Checks whether the character is ASCII 7 bit numeric.

* *
     *   CharUtils.isAsciiNumeric('a')  = false
     *   CharUtils.isAsciiNumeric('A')  = false
     *   CharUtils.isAsciiNumeric('3')  = true
     *   CharUtils.isAsciiNumeric('-')  = false
     *   CharUtils.isAsciiNumeric('\n') = false
     *   CharUtils.isAsciiNumeric('©') = false
     * 
* * @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'; } /** *

Checks whether the character is ASCII 7 bit numeric.

* *
     *   CharUtils.isAsciiAlphanumeric('a')  = true
     *   CharUtils.isAsciiAlphanumeric('A')  = true
     *   CharUtils.isAsciiAlphanumeric('3')  = true
     *   CharUtils.isAsciiAlphanumeric('-')  = false
     *   CharUtils.isAsciiAlphanumeric('\n') = false
     *   CharUtils.isAsciiAlphanumeric('©') = false
     * 
* * @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 ch >= 'A' && ch <= 'Z' || ch >= 'a' && ch <= 'z' || ch >= '0' && ch <= '9'; } // ----------------- Following code copied from Apache Harmony (Character class) /** * Indicates whether {@code ch} is a high- (or leading-) surrogate code unit * that is used for representing supplementary characters in UTF-16 * encoding. * * @param ch * the character to test. * @return {@code true} if {@code ch} is a high-surrogate code unit; * {@code false} otherwise. */ static boolean isHighSurrogate(final char ch) { return '\uD800' <= ch && '\uDBFF' >= ch; } // public static boolean isCharType(Class targetType) { return targetType.equals(Character.class) || targetType.equals(Character.TYPE); } }




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