https://eclipse.org/jetty/jetty-util: Utility classes for Jetty (Webtide) 
//
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// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under
// the terms of the Eclipse Public License 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0
//
// This Source Code may also be made available under the following
// Secondary Licenses when the conditions for such availability set
// forth in the Eclipse Public License, v. 2.0 are satisfied:
// the Apache License v2.0 which is available at
// https://www.apache.org/licenses/LICENSE-2.0
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package org.eclipse.jetty.util;

import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;


Fast String Utilities.
These string utilities provide both convenience methods and
performance improvements over most standard library versions. The
main aim of the optimizations is to avoid object creation unless
absolutely required.

/**
 * Fast String Utilities.
 *
 * These string utilities provide both convenience methods and
 * performance improvements over most standard library versions. The
 * main aim of the optimizations is to avoid object creation unless
 * absolutely required.
 */
public class StringUtil
{
    public static final String ALL_INTERFACES = "0.0.0.0";
    public static final String CRLF = "\r\n";
    public static final String DEFAULT_DELIMS = ",;";

    public static final String __ISO_8859_1 = "iso-8859-1";
    public static final String __UTF8 = "utf-8";
    public static final String __UTF16 = "utf-16";

    private static final Index<String> CHARSETS = new Index.Builder<String>()
        .caseSensitive(false)
        .with("utf-8", __UTF8)
        .with("utf8", __UTF8)
        .with("utf-16", __UTF16)
        .with("utf16", __UTF16)
        .with("iso-8859-1", __ISO_8859_1)
        .with("iso_8859_1", __ISO_8859_1)
        .build();

    
Convert alternate charset names (eg utf8) to normalized
name (eg UTF-8).

Params:
  • s – the charset to normalize
Returns:the normalized charset (or null if normalized version not found)
/**
     * Convert alternate charset names (eg utf8) to normalized
     * name (eg UTF-8).
     *
     * @param s the charset to normalize
     * @return the normalized charset (or null if normalized version not found)
     */
    public static String normalizeCharset(String s)
    {
        String n = CHARSETS.get(s);
        return (n == null) ? s : n;
    }

    
Convert alternate charset names (eg utf8) to normalized
name (eg UTF-8).

Params:
  • s – the charset to normalize
  • offset – the offset in the charset
  • length – the length of the charset in the input param
Returns:the normalized charset (or null if not found)
/**
     * Convert alternate charset names (eg utf8) to normalized
     * name (eg UTF-8).
     *
     * @param s the charset to normalize
     * @param offset the offset in the charset
     * @param length the length of the charset in the input param
     * @return the normalized charset (or null if not found)
     */
    public static String normalizeCharset(String s, int offset, int length)
    {
        String n = CHARSETS.get(s, offset, length);
        return (n == null) ? s.substring(offset, offset + length) : n;
    }

    // @checkstyle-disable-check : IllegalTokenTextCheck

    public static final char[] lowercases =
    {
        '\000', '\001', '\002', '\003', '\004', '\005', '\006', '\007',
        '\010', '\011', '\012', '\013', '\014', '\015', '\016', '\017',
        '\020', '\021', '\022', '\023', '\024', '\025', '\026', '\027',
        '\030', '\031', '\032', '\033', '\034', '\035', '\036', '\037',
        '\040', '\041', '\042', '\043', '\044', '\045', '\046', '\047',
        '\050', '\051', '\052', '\053', '\054', '\055', '\056', '\057',
        '\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067',
        '\070', '\071', '\072', '\073', '\074', '\075', '\076', '\077',
        '\100', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
        '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
        '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
        '\170', '\171', '\172', '\133', '\134', '\135', '\136', '\137',
        '\140', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
        '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
        '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
        '\170', '\171', '\172', '\173', '\174', '\175', '\176', '\177'
    };

    // @checkstyle-enable-check : IllegalTokenTextCheck

    
fast lower case conversion. Only works on ascii (not unicode)

Params:
  • s – the string to convert
Returns:a lower case version of s
/**
     * fast lower case conversion. Only works on ascii (not unicode)
     *
     * @param s the string to convert
     * @return a lower case version of s
     */
    public static String asciiToLowerCase(String s)
    {
        if (s == null)
            return null;

        char[] c = null;
        int i = s.length();
        // look for first conversion
        while (i-- > 0)
        {
            char c1 = s.charAt(i);
            if (c1 <= 127)
            {
                char c2 = lowercases[c1];
                if (c1 != c2)
                {
                    c = s.toCharArray();
                    c[i] = c2;
                    break;
                }
            }
        }
        while (i-- > 0)
        {
            if (c[i] <= 127)
                c[i] = lowercases[c[i]];
        }

        return c == null ? s : new String(c);
    }

    
Replace all characters from input string that are known to have
special meaning in various filesystems.

 This will replace all of the following characters with a "_" (underscore). 


    

  • Control Characters
    • 

  • Anything not 7-bit printable ASCII
    • 

  • Special characters: pipe, redirect, combine, slash, equivalence, bang, glob, selection, etc...
    • 

  • Space
    • 



Params:
  • str – the raw input string
Returns:the sanitized output string. or null if str is null.
/**
     * Replace all characters from input string that are known to have
     * special meaning in various filesystems.
     *
     * <p>
     * This will replace all of the following characters
     * with a "{@code _}" (underscore).
     * </p>
     * <ul>
     * <li>Control Characters</li>
     * <li>Anything not 7-bit printable ASCII</li>
     * <li>Special characters: pipe, redirect, combine, slash, equivalence, bang, glob, selection, etc...</li>
     * <li>Space</li>
     * </ul>
     *
     * @param str the raw input string
     * @return the sanitized output string. or null if {@code str} is null.
     */
    public static String sanitizeFileSystemName(String str)
    {
        if (str == null)
            return null;

        char[] chars = str.toCharArray();
        int len = chars.length;
        for (int i = 0; i < len; i++)
        {
            char c = chars[i];
            if ((c <= 0x1F) || // control characters
                (c >= 0x7F) || // over 7-bit printable ASCII
                // piping : special meaning on unix / osx / windows
                (c == '|') || (c == '>') || (c == '<') || (c == '/') || (c == '&') ||
                // special characters on windows
                (c == '\\') || (c == '.') || (c == ':') ||
                // special characters on osx
                (c == '=') || (c == '"') || (c == ',') ||
                // glob / selection characters on most OS's
                (c == '*') || (c == '?') ||
                // bang execution on unix / osx
                (c == '!') ||
                // spaces are just generally difficult to work with
                (c == ' '))
            {
                chars[i] = '_';
            }
        }
        return String.valueOf(chars);
    }

    public static boolean startsWithIgnoreCase(String s, String w)
    {
        if (w == null)
            return true;

        if (s == null || s.length() < w.length())
            return false;

        for (int i = 0; i < w.length(); i++)
        {
            char c1 = s.charAt(i);
            char c2 = w.charAt(i);
            if (c1 != c2)
            {
                if (c1 <= 127)
                    c1 = lowercases[c1];
                if (c2 <= 127)
                    c2 = lowercases[c2];
                if (c1 != c2)
                    return false;
            }
        }
        return true;
    }

    public static boolean endsWithIgnoreCase(String s, String w)
    {
        if (w == null)
            return true;
        if (s == null)
            return false;

        int sl = s.length();
        int wl = w.length();

        if (sl < wl)
            return false;

        for (int i = wl; i-- > 0; )
        {
            char c1 = s.charAt(--sl);
            char c2 = w.charAt(i);
            if (c1 != c2)
            {
                if (c1 <= 127)
                    c1 = lowercases[c1];
                if (c2 <= 127)
                    c2 = lowercases[c2];
                if (c1 != c2)
                    return false;
            }
        }
        return true;
    }

    
returns the next index of a character from the chars string

Params:
  • s – the input string to search
  • chars – the chars to look for
Returns:the index of the character in the input stream found.
/**
     * returns the next index of a character from the chars string
     *
     * @param s the input string to search
     * @param chars the chars to look for
     * @return the index of the character in the input stream found.
     */
    public static int indexFrom(String s, String chars)
    {
        for (int i = 0; i < s.length(); i++)
        {
            if (chars.indexOf(s.charAt(i)) >= 0)
                return i;
        }
        return -1;
    }

    
Replace chars within string.

 Fast replacement for java.lang.String#String.replace(char, char) 


Params:
  • str – the input string
  • find – the char to look for
  • with – the char to replace with
Returns:the now replaced string
/**
     * Replace chars within string.
     * <p>
     * Fast replacement for {@code java.lang.String#}{@link String#replace(char, char)}
     * </p>
     *
     * @param str the input string
     * @param find the char to look for
     * @param with the char to replace with
     * @return the now replaced string
     */
    public static String replace(String str, char find, char with)
    {
        if (str == null)
            return null;

        if (find == with)
            return str;

        int c = 0;
        int idx = str.indexOf(find, c);
        if (idx == -1)
        {
            return str;
        }
        char[] chars = str.toCharArray();
        int len = chars.length;
        for (int i = idx; i < len; i++)
        {
            if (chars[i] == find)
                chars[i] = with;
        }
        return String.valueOf(chars);
    }

    
Replace substrings within string.

 Fast replacement for java.lang.String#String.replace(CharSequence, CharSequence) 


Params:
  • s – the input string
  • sub – the string to look for
  • with – the string to replace with
Returns:the now replaced string
/**
     * Replace substrings within string.
     * <p>
     * Fast replacement for {@code java.lang.String#}{@link String#replace(CharSequence, CharSequence)}
     * </p>
     *
     * @param s the input string
     * @param sub the string to look for
     * @param with the string to replace with
     * @return the now replaced string
     */
    public static String replace(String s, String sub, String with)
    {
        if (s == null)
            return null;

        int c = 0;
        int i = s.indexOf(sub, c);
        if (i == -1)
        {
            return s;
        }
        StringBuilder buf = new StringBuilder(s.length() + with.length());
        do
        {
            buf.append(s, c, i);
            buf.append(with);
            c = i + sub.length();
        }
        while ((i = s.indexOf(sub, c)) != -1);
        if (c < s.length())
        {
            buf.append(s.substring(c));
        }
        return buf.toString();
    }

    
Replace first substrings within string.

 Fast replacement for java.lang.String#String.replaceFirst(String, String), but without Regex support. 


Params:
  • original – the original string
  • target – the target string to look for
  • replacement – the replacement string to use
Returns:the replaced string
/**
     * Replace first substrings within string.
     * <p>
     * Fast replacement for {@code java.lang.String#}{@link String#replaceFirst(String, String)}, but without
     * Regex support.
     * </p>
     *
     * @param original the original string
     * @param target the target string to look for
     * @param replacement the replacement string to use
     * @return the replaced string
     */
    public static String replaceFirst(String original, String target, String replacement)
    {
        int idx = original.indexOf(target);
        if (idx == -1)
            return original;

        int offset = 0;
        int originalLen = original.length();
        StringBuilder buf = new StringBuilder(originalLen + replacement.length());
        buf.append(original, offset, idx);
        offset += idx + target.length();
        buf.append(replacement);
        buf.append(original, offset, originalLen);

        return buf.toString();
    }

    
Append substring to StringBuilder

Params:
  • buf – StringBuilder to append to
  • s – String to append from
  • offset – The offset of the substring
  • length – The length of the substring
/**
     * Append substring to StringBuilder
     *
     * @param buf StringBuilder to append to
     * @param s String to append from
     * @param offset The offset of the substring
     * @param length The length of the substring
     */
    public static void append(StringBuilder buf,
                              String s,
                              int offset,
                              int length)
    {
        synchronized (buf)
        {
            int end = offset + length;
            for (int i = offset; i < end; i++)
            {
                if (i >= s.length())
                    break;
                buf.append(s.charAt(i));
            }
        }
    }

    
append hex digit

Params:
  • buf – the buffer to append to
  • b – the byte to append
  • base – the base of the hex output (almost always 16).
/**
     * append hex digit
     *
     * @param buf the buffer to append to
     * @param b the byte to append
     * @param base the base of the hex output (almost always 16).
     */
    public static void append(StringBuilder buf, byte b, int base)
    {
        int bi = 0xff & b;
        int c = '0' + (bi / base) % base;
        if (c > '9')
            c = 'a' + (c - '0' - 10);
        buf.append((char)c);
        c = '0' + bi % base;
        if (c > '9')
            c = 'a' + (c - '0' - 10);
        buf.append((char)c);
    }

    
Append 2 digits (zero padded) to the StringBuffer

Params:
  • buf – the buffer to append to
  • i – the value to append
/**
     * Append 2 digits (zero padded) to the StringBuffer
     *
     * @param buf the buffer to append to
     * @param i the value to append
     */
    public static void append2digits(StringBuffer buf, int i)
    {
        if (i < 100)
        {
            buf.append((char)(i / 10 + '0'));
            buf.append((char)(i % 10 + '0'));
        }
    }

    
Append 2 digits (zero padded) to the StringBuilder

Params:
  • buf – the buffer to append to
  • i – the value to append
/**
     * Append 2 digits (zero padded) to the StringBuilder
     *
     * @param buf the buffer to append to
     * @param i the value to append
     */
    public static void append2digits(StringBuilder buf, int i)
    {
        if (i < 100)
        {
            buf.append((char)(i / 10 + '0'));
            buf.append((char)(i % 10 + '0'));
        }
    }

    
Generate a string from another string repeated n times.

Params:
  • s – the string to use
  • n – the number of times this string should be appended
/**
     * Generate a string from another string repeated n times.
     *
     * @param s the string to use
     * @param n the number of times this string should be appended
     */
    public static String stringFrom(String s, int n)
    {
        StringBuilder stringBuilder = new StringBuilder(s.length() * n);
        for (int i = 0; i < n; i++)
        {
            stringBuilder.append(s);
        }
        return stringBuilder.toString();
    }

    
Return a non null string.

Params:
  • s – String
Returns:The string passed in or empty string if it is null.
/**
     * Return a non null string.
     *
     * @param s String
     * @return The string passed in or empty string if it is null.
     */
    public static String nonNull(String s)
    {
        if (s == null)
            return "";
        return s;
    }

    public static boolean equals(String s, char[] buf, int offset, int length)
    {
        if (s.length() != length)
            return false;
        for (int i = 0; i < length; i++)
        {
            if (buf[offset + i] != s.charAt(i))
                return false;
        }
        return true;
    }

    public static String toUTF8String(byte[] b, int offset, int length)
    {
        return new String(b, offset, length, StandardCharsets.UTF_8);
    }

    public static String toString(byte[] b, int offset, int length, String charset)
    {
        try
        {
            return new String(b, offset, length, charset);
        }
        catch (UnsupportedEncodingException e)
        {
            throw new IllegalArgumentException(e);
        }
    }

    
Find the index of a control characters in String


This will return a result on the first occurrence of a control character, regardless if
there are more than one.



 Note: uses codepoint version of Character.isISOControl(int) to support Unicode better. 


  indexOfControlChars(null)      == -1
  indexOfControlChars("")        == -1
  indexOfControlChars("\r\n")    == 0
  indexOfControlChars("\t")      == 0
  indexOfControlChars("   ")     == -1
  indexOfControlChars("a")       == -1
  indexOfControlChars(".")       == -1
  indexOfControlChars(";\n")     == 1
  indexOfControlChars("abc\f")   == 3
  indexOfControlChars("z\010")   == 1
  indexOfControlChars(":\u001c") == 1



Params:
  • str – the string to test.
Returns:the index of first control character in string, -1 if no control characters encountered
/**
     * Find the index of a control characters in String
     * <p>
     * This will return a result on the first occurrence of a control character, regardless if
     * there are more than one.
     * </p>
     * <p>
     * Note: uses codepoint version of {@link Character#isISOControl(int)} to support Unicode better.
     * </p>
     *
     * <pre>
     *   indexOfControlChars(null)      == -1
     *   indexOfControlChars("")        == -1
     *   indexOfControlChars("\r\n")    == 0
     *   indexOfControlChars("\t")      == 0
     *   indexOfControlChars("   ")     == -1
     *   indexOfControlChars("a")       == -1
     *   indexOfControlChars(".")       == -1
     *   indexOfControlChars(";\n")     == 1
     *   indexOfControlChars("abc\f")   == 3
     *   indexOfControlChars("z\010")   == 1
     *   indexOfControlChars(":\u001c") == 1
     * </pre>
     *
     * @param str the string to test.
     * @return the index of first control character in string, -1 if no control characters encountered
     */
    public static int indexOfControlChars(String str)
    {
        if (str == null)
        {
            return -1;
        }
        int len = str.length();
        for (int i = 0; i < len; i++)
        {
            if (Character.isISOControl(str.codePointAt(i)))
            {
                // found a control character, we can stop searching  now
                return i;
            }
        }
        // no control characters
        return -1;
    }

    
Test if a string is null or only has whitespace characters in it.

 Note: uses codepoint version of Character.isWhitespace(int) to support Unicode better. 
  isBlank(null)   == true
  isBlank("")     == true
  isBlank("\r\n") == true
  isBlank("\t")   == true
  isBlank("   ")  == true
  isBlank("a")    == false
  isBlank(".")    == false
  isBlank(";\n")  == false



Params:
  • str – the string to test.
Returns:true if string is null or only whitespace characters, false if non-whitespace characters encountered.
/**
     * Test if a string is null or only has whitespace characters in it.
     * <p>
     * Note: uses codepoint version of {@link Character#isWhitespace(int)} to support Unicode better.
     *
     * <pre>
     *   isBlank(null)   == true
     *   isBlank("")     == true
     *   isBlank("\r\n") == true
     *   isBlank("\t")   == true
     *   isBlank("   ")  == true
     *   isBlank("a")    == false
     *   isBlank(".")    == false
     *   isBlank(";\n")  == false
     * </pre>
     *
     * @param str the string to test.
     * @return true if string is null or only whitespace characters, false if non-whitespace characters encountered.
     */
    public static boolean isBlank(String str)
    {
        if (str == null)
        {
            return true;
        }
        int len = str.length();
        for (int i = 0; i < len; i++)
        {
            if (!Character.isWhitespace(str.codePointAt(i)))
            {
                // found a non-whitespace, we can stop searching  now
                return false;
            }
        }
        // only whitespace
        return true;
    }

    
Checks if a String is empty ("") or null.


  isEmpty(null)   == true
  isEmpty("")     == true
  isEmpty("\r\n") == false
  isEmpty("\t")   == false
  isEmpty("   ")  == false
  isEmpty("a")    == false
  isEmpty(".")    == false
  isEmpty(";\n")  == false



Params:
  • str – the string to test.
Returns:true if string is null or empty.
/**
     * <p>Checks if a String is empty ("") or null.</p>
     *
     * <pre>
     *   isEmpty(null)   == true
     *   isEmpty("")     == true
     *   isEmpty("\r\n") == false
     *   isEmpty("\t")   == false
     *   isEmpty("   ")  == false
     *   isEmpty("a")    == false
     *   isEmpty(".")    == false
     *   isEmpty(";\n")  == false
     * </pre>
     *
     * @param str the string to test.
     * @return true if string is null or empty.
     */
    public static boolean isEmpty(String str)
    {
        return str == null || str.isEmpty();
    }

    
Test if a string is not null and contains at least 1 non-whitespace characters in it.

 Note: uses codepoint version of Character.isWhitespace(int) to support Unicode better. 
  isNotBlank(null)   == false
  isNotBlank("")     == false
  isNotBlank("\r\n") == false
  isNotBlank("\t")   == false
  isNotBlank("   ")  == false
  isNotBlank("a")    == true
  isNotBlank(".")    == true
  isNotBlank(";\n")  == true



Params:
  • str – the string to test.
Returns:true if string is not null and has at least 1 non-whitespace character, false if null or all-whitespace characters.
/**
     * Test if a string is not null and contains at least 1 non-whitespace characters in it.
     * <p>
     * Note: uses codepoint version of {@link Character#isWhitespace(int)} to support Unicode better.
     *
     * <pre>
     *   isNotBlank(null)   == false
     *   isNotBlank("")     == false
     *   isNotBlank("\r\n") == false
     *   isNotBlank("\t")   == false
     *   isNotBlank("   ")  == false
     *   isNotBlank("a")    == true
     *   isNotBlank(".")    == true
     *   isNotBlank(";\n")  == true
     * </pre>
     *
     * @param str the string to test.
     * @return true if string is not null and has at least 1 non-whitespace character, false if null or all-whitespace characters.
     */
    public static boolean isNotBlank(String str)
    {
        if (str == null)
        {
            return false;
        }
        int len = str.length();
        for (int i = 0; i < len; i++)
        {
            if (!Character.isWhitespace(str.codePointAt(i)))
            {
                // found a non-whitespace, we can stop searching  now
                return true;
            }
        }
        // only whitespace
        return false;
    }

    public static boolean isUTF8(String charset)
    {
        return __UTF8.equalsIgnoreCase(charset) || __UTF8.equalsIgnoreCase(normalizeCharset(charset));
    }

    public static boolean isHex(String str, int offset, int length)
    {
        if (offset + length > str.length())
        {
            return false;
        }

        for (int i = offset; i < (offset + length); i++)
        {
            char c = str.charAt(i);
            if (!(((c >= 'a') && (c <= 'f')) ||
                ((c >= 'A') && (c <= 'F')) ||
                ((c >= '0') && (c <= '9'))))
            {
                return false;
            }
        }
        return true;
    }

    public static String printable(String name)
    {
        if (name == null)
            return null;
        StringBuilder buf = new StringBuilder(name.length());
        for (int i = 0; i < name.length(); i++)
        {
            char c = name.charAt(i);
            if (!Character.isISOControl(c))
                buf.append(c);
        }
        return buf.toString();
    }

    public static String printable(byte[] b)
    {
        StringBuilder buf = new StringBuilder();
        for (int i = 0; i < b.length; i++)
        {
            char c = (char)b[i];
            if (Character.isWhitespace(c) || c > ' ' && c < 0x7f)
                buf.append(c);
            else
            {
                buf.append("0x");
                TypeUtil.toHex(b[i], buf);
            }
        }
        return buf.toString();
    }

    public static byte[] getBytes(String s)
    {
        return s.getBytes(StandardCharsets.ISO_8859_1);
    }

    public static byte[] getBytes(String s, String charset)
    {
        try
        {
            return s.getBytes(charset);
        }
        catch (Exception e)
        {
            return s.getBytes();
        }
    }

    public static byte[] getUtf8Bytes(String s)
    {
        return s.getBytes(StandardCharsets.UTF_8);
    }

    
Convert String to an integer. Parses up to the first non-numeric character. If no number is found an IllegalArgumentException is thrown

Params:
  • string – A String containing an integer.
  • from – The index to start parsing from
Returns:an int
/**
     * Convert String to an integer. Parses up to the first non-numeric character. If no number is found an IllegalArgumentException is thrown
     *
     * @param string A String containing an integer.
     * @param from The index to start parsing from
     * @return an int
     */
    public static int toInt(String string, int from)
    {
        int val = 0;
        boolean started = false;
        boolean minus = false;
        for (int i = from; i < string.length(); i++)
        {
            char b = string.charAt(i);
            if (b <= ' ')
            {
                if (started)
                    break;
            }
            else if (b >= '0' && b <= '9')
            {
                val = val * 10 + (b - '0');
                started = true;
            }
            else if (b == '-' && !started)
            {
                minus = true;
            }
            else
                break;
        }
        if (started)
            return minus ? (-val) : val;
        throw new NumberFormatException(string);
    }

    
Convert String to an long. Parses up to the first non-numeric character. If no number is found an IllegalArgumentException is thrown

Params:
  • string – A String containing an integer.
Returns:an int
/**
     * Convert String to an long. Parses up to the first non-numeric character. If no number is found an IllegalArgumentException is thrown
     *
     * @param string A String containing an integer.
     * @return an int
     */
    public static long toLong(String string)
    {
        long val = 0;
        boolean started = false;
        boolean minus = false;
        for (int i = 0; i < string.length(); i++)
        {
            char b = string.charAt(i);
            if (b <= ' ')
            {
                if (started)
                    break;
            }
            else if (b >= '0' && b <= '9')
            {
                val = val * 10L + (b - '0');
                started = true;
            }
            else if (b == '-' && !started)
            {
                minus = true;
            }
            else
                break;
        }
        if (started)
            return minus ? (-val) : val;
        throw new NumberFormatException(string);
    }

    
Truncate a string to a max size.

Params:
  • str – the string to possibly truncate
  • maxSize – the maximum size of the string
Returns:the truncated string.  if str param is null, then the returned string will also be null.
/**
     * Truncate a string to a max size.
     *
     * @param str the string to possibly truncate
     * @param maxSize the maximum size of the string
     * @return the truncated string.  if <code>str</code> param is null, then the returned string will also be null.
     */
    public static String truncate(String str, int maxSize)
    {
        if (str == null)
        {
            return null;
        }
        if (str.length() <= maxSize)
        {
            return str;
        }
        return str.substring(0, maxSize);
    }

    
Parse the string representation of a list using csvSplit(List<String>, String, int, int) 
Params:
  • s – The string to parse, expected to be enclosed as '[...]'
Returns:An array of parsed values.
/**
     * Parse the string representation of a list using {@link #csvSplit(List, String, int, int)}
     *
     * @param s The string to parse, expected to be enclosed as '[...]'
     * @return An array of parsed values.
     */
    public static String[] arrayFromString(String s)
    {
        if (s == null)
            return new String[]{};
        if (!s.startsWith("[") || !s.endsWith("]"))
            throw new IllegalArgumentException();
        if (s.length() == 2)
            return new String[]{};
        return csvSplit(s, 1, s.length() - 2);
    }

    
Params:
  • s – The string to parse
Returns:An array of parsed values.
/**
     * Parse a CSV string using {@link #csvSplit(List, String, int, int)}
     *
     * @param s The string to parse
     * @return An array of parsed values.
     */
    public static String[] csvSplit(String s)
    {
        if (s == null)
            return null;
        return csvSplit(s, 0, s.length());
    }

    
Params:
  • s – The string to parse
  • off – The offset into the string to start parsing
  • len – The len in characters to parse
Returns:An array of parsed values.
/**
     * Parse a CSV string using {@link #csvSplit(List, String, int, int)}
     *
     * @param s The string to parse
     * @param off The offset into the string to start parsing
     * @param len The len in characters to parse
     * @return An array of parsed values.
     */
    public static String[] csvSplit(String s, int off, int len)
    {
        if (s == null)
            return null;
        if (off < 0 || len < 0 || off > s.length())
            throw new IllegalArgumentException();
        List<String> list = new ArrayList<>();
        csvSplit(list, s, off, len);
        return list.toArray(new String[list.size()]);
    }

    enum CsvSplitState
    {
        PRE_DATA, QUOTE, SLOSH, DATA, WHITE, POST_DATA
    }

    
Split a quoted comma separated string to a list

Handle rfc4180-like
CSV strings, with the exceptions:
    

  • quoted values may contain double quotes escaped with back-slash

  • Non-quoted values are trimmed of leading trailing white space

  • trailing commas are ignored

  • double commas result in a empty string value



Params:
  • list – The Collection to split to (or null to get a new list)
  • s – The string to parse
  • off – The offset into the string to start parsing
  • len – The len in characters to parse
Returns:list containing the parsed list values
/**
     * Split a quoted comma separated string to a list
     * <p>Handle <a href="https://www.ietf.org/rfc/rfc4180.txt">rfc4180</a>-like
     * CSV strings, with the exceptions:<ul>
     * <li>quoted values may contain double quotes escaped with back-slash
     * <li>Non-quoted values are trimmed of leading trailing white space
     * <li>trailing commas are ignored
     * <li>double commas result in a empty string value
     * </ul>
     *
     * @param list The Collection to split to (or null to get a new list)
     * @param s The string to parse
     * @param off The offset into the string to start parsing
     * @param len The len in characters to parse
     * @return list containing the parsed list values
     */
    public static List<String> csvSplit(List<String> list, String s, int off, int len)
    {
        if (list == null)
            list = new ArrayList<>();
        CsvSplitState state = CsvSplitState.PRE_DATA;
        StringBuilder out = new StringBuilder();
        int last = -1;
        while (len > 0)
        {
            char ch = s.charAt(off++);
            len--;

            switch (state)
            {
                case PRE_DATA:
                    if (Character.isWhitespace(ch))
                        continue;
                    if ('"' == ch)
                    {
                        state = CsvSplitState.QUOTE;
                        continue;
                    }

                    if (',' == ch)
                    {
                        list.add("");
                        continue;
                    }
                    state = CsvSplitState.DATA;
                    out.append(ch);
                    continue;

                case DATA:
                    if (Character.isWhitespace(ch))
                    {
                        last = out.length();
                        out.append(ch);
                        state = CsvSplitState.WHITE;
                        continue;
                    }

                    if (',' == ch)
                    {
                        list.add(out.toString());
                        out.setLength(0);
                        state = CsvSplitState.PRE_DATA;
                        continue;
                    }
                    out.append(ch);
                    continue;

                case WHITE:
                    if (Character.isWhitespace(ch))
                    {
                        out.append(ch);
                        continue;
                    }

                    if (',' == ch)
                    {
                        out.setLength(last);
                        list.add(out.toString());
                        out.setLength(0);
                        state = CsvSplitState.PRE_DATA;
                        continue;
                    }

                    state = CsvSplitState.DATA;
                    out.append(ch);
                    last = -1;
                    continue;

                case QUOTE:
                    if ('\\' == ch)
                    {
                        state = CsvSplitState.SLOSH;
                        continue;
                    }
                    if ('"' == ch)
                    {
                        list.add(out.toString());
                        out.setLength(0);
                        state = CsvSplitState.POST_DATA;
                        continue;
                    }
                    out.append(ch);
                    continue;

                case SLOSH:
                    out.append(ch);
                    state = CsvSplitState.QUOTE;
                    continue;

                case POST_DATA:
                    if (',' == ch)
                    {
                        state = CsvSplitState.PRE_DATA;
                        continue;
                    }
                    continue;

                default:
                    throw new IllegalStateException(state.toString());
            }
        }
        switch (state)
        {
            case PRE_DATA:
            case POST_DATA:
                break;

            case DATA:
            case QUOTE:
            case SLOSH:
                list.add(out.toString());
                break;

            case WHITE:
                out.setLength(last);
                list.add(out.toString());
                break;

            default:
                throw new IllegalStateException(state.toString());
        }

        return list;
    }

    public static String sanitizeXmlString(String html)
    {
        if (html == null)
            return null;

        int i = 0;

        // Are there any characters that need sanitizing?
        loop:
        for (; i < html.length(); i++)
        {
            char c = html.charAt(i);
            switch (c)
            {
                case '&':
                case '<':
                case '>':
                case '\'':
                case '"':
                    break loop;
                default:
                    if (Character.isISOControl(c) && !Character.isWhitespace(c))
                        break loop;
            }
        }
        // No characters need sanitizing, so return original string
        if (i == html.length())
            return html;

        // Create builder with OK content so far 
        StringBuilder out = new StringBuilder(html.length() * 4 / 3);
        out.append(html, 0, i);

        // sanitize remaining content
        for (; i < html.length(); i++)
        {
            char c = html.charAt(i);
            switch (c)
            {
                case '&':
                    out.append("&amp;");
                    break;
                case '<':
                    out.append("&lt;");
                    break;
                case '>':
                    out.append("&gt;");
                    break;
                case '\'':
                    out.append("&apos;");
                    break;
                case '"':
                    out.append("&quot;");
                    break;
                default:
                    if (Character.isISOControl(c) && !Character.isWhitespace(c))
                        out.append('?');
                    else
                        out.append(c);
            }
        }
        return out.toString();
    }

    public static String strip(String str, String find)
    {
        return StringUtil.replace(str, find, "");
    }

    
The String value of an Object

This method calls String.valueOf(Object) unless the object is null, in which case null is returned


Params:
  • object – The object
Returns:String value or null
/**
     * The String value of an Object
     * <p>This method calls {@link String#valueOf(Object)} unless the object is null,
     * in which case null is returned</p>
     *
     * @param object The object
     * @return String value or null
     */
    public static String valueOf(Object object)
    {
        return object == null ? null : String.valueOf(object);
    }
}