Package org.eclipse.jetty.util

Class StringUtil

java.lang.Object

org.eclipse.jetty.util.StringUtil

public class StringUtil
extends Object

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.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	__ISO_8859_1
static final String	__UTF16
static final String	__UTF8
static final String	ALL_INTERFACES
static final String	CRLF
static final String	DEFAULT_DELIMS

Constructor Summary

Constructors

Constructor	Description
StringUtil()

Method Summary

Modifier and Type	Method	Description
static void	append(StringBuilder buf, byte b, int base)	append hex digit
static void	append(StringBuilder buf, String s, int offset, int length)	Append substring to StringBuilder
static void	append2digits(StringBuffer buf, int i)	Append 2 digits (zero padded) to the StringBuffer
static void	append2digits(StringBuilder buf, int i)	Append 2 digits (zero padded) to the StringBuilder
static String[]	arrayFromString(String s)	Parse the string representation of a list using csvSplit(List, String, int, int)
static byte	asciiToLowerCase(byte c)	fast lower case conversion.
static char	asciiToLowerCase(char c)	fast lower case conversion.
static String	asciiToLowerCase(String s)	fast lower case conversion.
static byte	asciiToUpperCase(byte c)	fast upper case conversion.
static char	asciiToUpperCase(char c)	fast upper case conversion.
static String	asciiToUpperCase(String s)	fast upper case conversion.
static String[]	csvSplit(String s)	Parse a CSV string using csvSplit(List, String, int, int)
static String[]	csvSplit(String s, int off, int len)	Parse a CSV string using csvSplit(List, String, int, int)
static List<String>	csvSplit(List<String> list, String s, int off, int len)	Split a quoted comma separated string to a list
static boolean	endsWithIgnoreCase(String s, String w)
static boolean	equals(String s, char[] buf, int offset, int length)
static byte[]	fromHexString(String s)
static byte[]	getBytes(String s)
static byte[]	getBytes(String s, String charset)
static int	getLength(String s)	Get the length of a string where a null string is length 0.
static byte[]	getUtf8Bytes(String s)
static int	indexFrom(String s, String chars)	returns the next index of a character from the chars string
static int	indexOfControlChars(String str)	Find the index of a control characters in String
static boolean	isBlank(String str)	Test if a string is null or only has whitespace characters in it.
static boolean	isEmpty(String str)	Checks if a String is empty ("") or null.
static boolean	isHex(String str, int offset, int length)
static boolean	isNotBlank(String str)	Test if a string is not null and contains at least 1 non-whitespace characters in it.
static boolean	isUTF8(String charset)
static String	nonNull(String s)	Return a non null string.
static String	normalizeCharset(String s)	Convert alternate charset names (eg utf8) to normalized name (eg UTF-8).
static String	normalizeCharset(String s, int offset, int length)	Convert alternate charset names (eg utf8) to normalized name (eg UTF-8).
static String	printable(byte[] b)
static String	printable(String name)
static String	replace(String str, char find, char with)	Replace chars within string.
static String	replace(String s, String sub, String with)	Replace substrings within string.
static String	replaceFirst(String original, String target, String replacement)	Replace first substrings within string.
static String	sanitizeFileSystemName(String str)	Replace all characters from input string that are known to have special meaning in various filesystems.
static String	sanitizeXmlString(String html)
static boolean	startsWithIgnoreCase(String s, String w)
static String	stringFrom(String s, int n)	Generate a string from another string repeated n times.
static String	strip(String str, String find)
static String	toHexString(byte b)
static String	toHexString(byte[] b)
static String	toHexString(byte[] b, int offset, int length)
static int	toInt(String string, int from)	Convert String to an integer.
static long	toLong(String string)	Convert String to an long.
static String	toString(byte[] b, int offset, int length, String charset)	Deprecated, for removal: This API element is subject to removal in a future version. use String(byte[], int, int, Charset) instead
static String	toUTF8String(byte[] b, int offset, int length)
static String	truncate(String str, int maxSize)	Truncate a string to a max size.
static String	valueOf(Object object)	The String value of an Object

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

ALL_INTERFACES

public static final String ALL_INTERFACES

See Also:

• Constant Field Values

CRLF

public static final String CRLF

See Also:

• Constant Field Values

DEFAULT_DELIMS

public static final String DEFAULT_DELIMS

See Also:

• Constant Field Values

__ISO_8859_1

public static final String __ISO_8859_1

See Also:

• Constant Field Values

__UTF8

public static final String __UTF8

See Also:

• Constant Field Values

__UTF16

public static final String __UTF16

See Also:

• Constant Field Values

Constructor Details

StringUtil

public StringUtil()

Method Details

normalizeCharset

public static String normalizeCharset(String s)

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

Parameters:

s - the charset to normalize

Returns:

the normalized charset (or null if normalized version not found)

normalizeCharset

public static String normalizeCharset(String s,
 int offset,
 int length)

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

Parameters:

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)

asciiToLowerCase

public static char asciiToLowerCase(char c)

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

Parameters:

c - the char to convert

Returns:

a lower case version of c

asciiToLowerCase

public static byte asciiToLowerCase(byte c)

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

Parameters:

c - the byte to convert

Returns:

a lower case version of c

asciiToUpperCase

public static char asciiToUpperCase(char c)

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

Parameters:

c - the char to convert

Returns:

a upper case version of c

asciiToUpperCase

public static byte asciiToUpperCase(byte c)

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

Parameters:

c - the byte to convert

Returns:

a upper case version of c

asciiToLowerCase

public static String asciiToLowerCase(String s)

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

Parameters:

s - the string to convert

Returns:

a lower case version of s

asciiToUpperCase

public static String asciiToUpperCase(String s)

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

Parameters:

s - the string to convert

Returns:

a lower case version of s

sanitizeFileSystemName

public static String sanitizeFileSystemName(String str)

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

Parameters:

str - the raw input string

Returns:

the sanitized output string. or null if str is null.

startsWithIgnoreCase

public static boolean startsWithIgnoreCase(String s,
 String w)

endsWithIgnoreCase

public static boolean endsWithIgnoreCase(String s,
 String w)

indexFrom

public static int indexFrom(String s,
 String chars)

returns the next index of a character from the chars string

Parameters:

s - the input string to search

chars - the chars to look for

Returns:

the index of the character in the input stream found.

replace

public static String replace(String str,
 char find,
 char with)

Replace chars within string.

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

Parameters:

str - the input string

find - the char to look for

with - the char to replace with

Returns:

the now replaced string

replace

public static String replace(String s,
 String sub,
 String with)

Replace substrings within string.

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

Parameters:

s - the input string

sub - the string to look for

with - the string to replace with

Returns:

the now replaced string

replaceFirst

public static String replaceFirst(String original,
 String target,
 String replacement)

Replace first substrings within string.

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

Parameters:

original - the original string

target - the target string to look for

replacement - the replacement string to use

Returns:

the replaced string

append

public static void append(StringBuilder buf,
 String s,
 int offset,
 int length)

Append substring to StringBuilder

Parameters:

buf - StringBuilder to append to

s - String to append from

offset - The offset of the substring

length - The length of the substring

append

public static void append(StringBuilder buf,
 byte b,
 int base)

append hex digit

Parameters:

buf - the buffer to append to

b - the byte to append

base - the base of the hex output (almost always 16).

append2digits

public static void append2digits(StringBuffer buf,
 int i)

Append 2 digits (zero padded) to the StringBuffer

Parameters:

buf - the buffer to append to

i - the value to append

append2digits

public static void append2digits(StringBuilder buf,
 int i)

Append 2 digits (zero padded) to the StringBuilder

Parameters:

buf - the buffer to append to

i - the value to append

stringFrom

public static String stringFrom(String s,
 int n)

Generate a string from another string repeated n times.

Parameters:

s - the string to use

n - the number of times this string should be appended

nonNull

public static String nonNull(String s)

Return a non null string.

Parameters:

s - String

Returns:

The string passed in or empty string if it is null.

equals

public static boolean equals(String s,
 char[] buf,
 int offset,
 int length)

toUTF8String

public static String toUTF8String(byte[] b,
 int offset,
 int length)

toString

@Deprecated(since="10",
            forRemoval=true)
public static String toString(byte[] b,
 int offset,
 int length,
 String charset)

Deprecated, for removal: This API element is subject to removal in a future version.

use String(byte[], int, int, Charset) instead

indexOfControlChars

public static int indexOfControlChars(String str)

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(":") == 1
 

Parameters:

str - the string to test.

Returns:

the index of first control character in string, -1 if no control characters encountered

isBlank

public static boolean isBlank(String str)

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
 

Parameters:

str - the string to test.

Returns:

true if string is null or only whitespace characters, false if non-whitespace characters encountered.

isEmpty

public static boolean isEmpty(String str)

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
 

Parameters:

str - the string to test.

Returns:

true if string is null or empty.

getLength

public static int getLength(String s)

Get the length of a string where a null string is length 0.

Parameters:

s - the string.

Returns:

the length of the string.

isNotBlank

public static boolean isNotBlank(String str)

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
 

Parameters:

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.

isUTF8

public static boolean isUTF8(String charset)

isHex

public static boolean isHex(String str,
 int offset,
 int length)

fromHexString

public static byte[] fromHexString(String s)

toHexString

public static String toHexString(byte b)

toHexString

public static String toHexString(byte[] b)

toHexString

public static String toHexString(byte[] b,
 int offset,
 int length)

printable

public static String printable(String name)

printable

public static String printable(byte[] b)

getBytes

public static byte[] getBytes(String s)

getBytes

public static byte[] getBytes(String s,
 String charset)

getUtf8Bytes

public static byte[] getUtf8Bytes(String s)

toInt

public static int toInt(String string,
 int from)

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

Parameters:

string - A String containing an integer.

from - The index to start parsing from

Returns:

an int

toLong

public static long toLong(String string)

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

Parameters:

string - A String containing an integer.

Returns:

an int

truncate

public static String truncate(String str,
 int maxSize)

Truncate a string to a max size.

Parameters:

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.

arrayFromString

public static String[] arrayFromString(String s)

Parse the string representation of a list using csvSplit(List, String, int, int)

Parameters:

s - The string to parse, expected to be enclosed as '[...]'

Returns:

An array of parsed values.

csvSplit

public static String[] csvSplit(String s)

Parse a CSV string using csvSplit(List, String, int, int)

Parameters:

s - The string to parse

Returns:

An array of parsed values.

csvSplit

public static String[] csvSplit(String s,
 int off,
 int len)

Parse a CSV string using csvSplit(List, String, int, int)

Parameters:

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.

csvSplit

public static List<String> csvSplit(List<String> list,
 String s,
 int off,
 int len)

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

Parameters:

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

sanitizeXmlString

public static String sanitizeXmlString(String html)

strip

public static String strip(String str,
 String find)

valueOf

public static String valueOf(Object object)

The String value of an Object

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

Parameters:

object - The object

Returns:

String value or null