org.apache.hadoop.util
Class StringUtils

java.lang.Object
  org.apache.hadoop.util.StringUtils

public class StringUtils
extends Object

General string utils

Nested Class Summary

static class

StringUtils.TraditionalBinaryPrefix The traditional binary prefixes, kilo, mega, ..., exa, which can be represented by a 64-bit integer.

Field Summary

static char	COMMA
static String	COMMA_STR
static char	ESCAPE_CHAR

Constructor Summary

StringUtils()

Method Summary

static String	arrayToString(String[] strs) Given an array of strings, return a comma-separated list of its elements.
static String	byteDesc(long len) Return an abbreviated English-language desc of the byte length
static String	byteToHexString(byte[] bytes) Same as byteToHexString(bytes, 0, bytes.length).
static String	byteToHexString(byte[] bytes, int start, int end) Given an array of bytes it will convert the bytes to a hex string representation of the bytes
static String	camelize(String s) Convert SOME_STUFF to SomeStuff
static String	capitalize(String s) Capitalize a word
static String	escapeHTML(String string) Escapes HTML Special characters present in the string.
static String	escapeString(String str) Escape commas in the string using the default escape char
static String	escapeString(String str, char escapeChar, char charToEscape) Escape charToEscape in the string with the escape char escapeChar
static String	escapeString(String str, char escapeChar, char[] charsToEscape)
static int	findNext(String str, char separator, char escapeChar, int start, StringBuilder split) Finds the first occurrence of the separator character ignoring the escaped separators starting from the index.
static String	formatPercent(double done, int digits) Format a percentage for presentation to the user.
static String	formatTime(long timeDiff) Given the time in long milliseconds, returns a String in the format Xhrs, Ymins, Z sec.
static String	formatTimeDiff(long finishTime, long startTime) Given a finish and start time in long milliseconds, returns a String in the format Xhrs, Ymins, Z sec, for the time difference between two times.
static String	getFormattedTimeWithDiff(DateFormat dateFormat, long finishTime, long startTime) Formats time in ms and appends difference (finishTime - startTime) as returned by formatTimeDiff().
static String	getHostname() Return hostname without throwing exception.
static Collection<String>	getStringCollection(String str) Returns a collection of strings.
static String[]	getStrings(String str) Returns an arraylist of strings.
static byte[]	hexStringToByte(String hex) Given a hexstring this will return the byte array corresponding to the string
static String	humanReadableInt(long number) Given an integer, return a string that is in an approximate, but human readable format.
static String	join(CharSequence separator, Iterable<String> strings) Concatenates strings, using a separator.
static String	join(CharSequence separator, String[] strings) Concatenates strings, using a separator.
static String	limitDecimalTo2(double d)
static String	simpleHostname(String fullHostname) Given a full hostname, return the word upto the first dot.
static String[]	split(String str) Split a string using the default separator
static String[]	split(String str, char escapeChar, char separator) Split a string using the given separator
static void	startupShutdownMessage(Class<?> clazz, String[] args, org.apache.commons.logging.Log LOG) Print a log message for starting up and shutting down
static String	stringifyException(Throwable e) Make a string representation of the exception.
static Path[]	stringToPath(String[] str)
static URI[]	stringToURI(String[] str)
static String	unEscapeString(String str) Unescape commas in the string using the default escape char
static String	unEscapeString(String str, char escapeChar, char charToEscape) Unescape charToEscape in the string with the escape char escapeChar
static String	unEscapeString(String str, char escapeChar, char[] charsToEscape)
static String	uriToString(URI[] uris)

Methods inherited from class java.lang.Object

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

Field Detail

COMMA

public static final char COMMA

See Also:

Constant Field Values

COMMA_STR

public static final String COMMA_STR

See Also:

Constant Field Values

ESCAPE_CHAR

public static final char ESCAPE_CHAR

See Also:

Constant Field Values

Constructor Detail

StringUtils

public StringUtils()

Method Detail

stringifyException

public static String stringifyException(Throwable e)

Make a string representation of the exception.

Parameters:

e - The exception to stringify

Returns:

A string with exception name and call stack.

simpleHostname

public static String simpleHostname(String fullHostname)

Given a full hostname, return the word upto the first dot.

Parameters:

fullHostname - the full hostname

Returns:

the hostname to the first dot

humanReadableInt

public static String humanReadableInt(long number)

Given an integer, return a string that is in an approximate, but human readable format. It uses the bases 'k', 'm', and 'g' for 1024, 1024**2, and 1024**3.

Parameters:

number - the number to format

Returns:

a human readable form of the integer

formatPercent

public static String formatPercent(double done,
                                   int digits)

Format a percentage for presentation to the user.

Parameters:

done - the percentage to format (0.0 to 1.0)

digits - the number of digits past the decimal point

Returns:

a string representation of the percentage

arrayToString

public static String arrayToString(String[] strs)

Given an array of strings, return a comma-separated list of its elements.

Parameters:

strs - Array of strings

Returns:

Empty string if strs.length is 0, comma separated list of strings otherwise

byteToHexString

public static String byteToHexString(byte[] bytes,
                                     int start,
                                     int end)

Given an array of bytes it will convert the bytes to a hex string representation of the bytes

Parameters:

bytes -

start - start index, inclusively

end - end index, exclusively

Returns:

hex string representation of the byte array

byteToHexString

public static String byteToHexString(byte[] bytes)

Same as byteToHexString(bytes, 0, bytes.length).

hexStringToByte

public static byte[] hexStringToByte(String hex)

Given a hexstring this will return the byte array corresponding to the string

Parameters:

hex - the hex String array

Returns:

a byte array that is a hex string representation of the given string. The size of the byte array is therefore hex.length/2

uriToString

public static String uriToString(URI[] uris)

Parameters:

uris -

stringToURI

public static URI[] stringToURI(String[] str)

Parameters:

str -

stringToPath

public static Path[] stringToPath(String[] str)

Parameters:

str -

formatTimeDiff

public static String formatTimeDiff(long finishTime,
                                    long startTime)

Given a finish and start time in long milliseconds, returns a String in the format Xhrs, Ymins, Z sec, for the time difference between two times. If finish time comes before start time then negative valeus of X, Y and Z wil return.

Parameters:

finishTime - finish time

startTime - start time

formatTime

public static String formatTime(long timeDiff)

Given the time in long milliseconds, returns a String in the format Xhrs, Ymins, Z sec.

Parameters:

timeDiff - The time difference to format

getFormattedTimeWithDiff

public static String getFormattedTimeWithDiff(DateFormat dateFormat,
                                              long finishTime,
                                              long startTime)

Formats time in ms and appends difference (finishTime - startTime) as returned by formatTimeDiff(). If finish time is 0, empty string is returned, if start time is 0 then difference is not appended to return value.

Parameters:

dateFormat - date format to use

finishTime - fnish time

startTime - start time

Returns:

formatted value.

getStrings

public static String[] getStrings(String str)

Returns an arraylist of strings.

Parameters:

str - the comma seperated string values

Returns:

the arraylist of the comma seperated string values

getStringCollection

public static Collection<String> getStringCollection(String str)

Returns a collection of strings.

Parameters:

str - comma seperated string values

Returns:

an ArrayList of string values

split

public static String[] split(String str)

Split a string using the default separator

Parameters:

str - a string that may have escaped separator

Returns:

an array of strings

split

public static String[] split(String str,
                             char escapeChar,
                             char separator)

Split a string using the given separator

Parameters:

str - a string that may have escaped separator

escapeChar - a char that be used to escape the separator

separator - a separator char

Returns:

an array of strings

findNext

public static int findNext(String str,
                           char separator,
                           char escapeChar,
                           int start,
                           StringBuilder split)

Finds the first occurrence of the separator character ignoring the escaped separators starting from the index. Note the substring between the index and the position of the separator is passed.

Parameters:

str - the source string

separator - the character to find

escapeChar - character used to escape

start - from where to search

split - used to pass back the extracted string

escapeString

public static String escapeString(String str)

Escape commas in the string using the default escape char

Parameters:

str - a string

Returns:

an escaped string

escapeString

public static String escapeString(String str,
                                  char escapeChar,
                                  char charToEscape)

Escape charToEscape in the string with the escape char escapeChar

Parameters:

str - string

escapeChar - escape char

charToEscape - the char to be escaped

Returns:

an escaped string

escapeString

public static String escapeString(String str,
                                  char escapeChar,
                                  char[] charsToEscape)

Parameters:

charsToEscape - array of characters to be escaped

unEscapeString

public static String unEscapeString(String str)

Unescape commas in the string using the default escape char

Parameters:

str - a string

Returns:

an unescaped string

unEscapeString

public static String unEscapeString(String str,
                                    char escapeChar,
                                    char charToEscape)

Unescape charToEscape in the string with the escape char escapeChar

Parameters:

str - string

escapeChar - escape char

charToEscape - the escaped char

Returns:

an unescaped string

unEscapeString

public static String unEscapeString(String str,
                                    char escapeChar,
                                    char[] charsToEscape)

Parameters:

charsToEscape - array of characters to unescape

getHostname

public static String getHostname()

Return hostname without throwing exception.

Returns:

hostname

startupShutdownMessage

public static void startupShutdownMessage(Class<?> clazz,
                                          String[] args,
                                          org.apache.commons.logging.Log LOG)

Print a log message for starting up and shutting down

Parameters:

clazz - the class of the server

args - arguments

LOG - the target log object

escapeHTML

public static String escapeHTML(String string)

Escapes HTML Special characters present in the string.

Parameters:

string -

Returns:

HTML Escaped String representation

byteDesc

public static String byteDesc(long len)

Return an abbreviated English-language desc of the byte length

limitDecimalTo2

public static String limitDecimalTo2(double d)

join

public static String join(CharSequence separator,
                          Iterable<String> strings)

Concatenates strings, using a separator.

Parameters:

separator - Separator to join with.

strings - Strings to join.

Returns:

the joined string

join

public static String join(CharSequence separator,
                          String[] strings)

Concatenates strings, using a separator.

Parameters:

separator - to join with

strings - to join

Returns:

the joined string

capitalize

public static String capitalize(String s)

Capitalize a word

Parameters:

s - the input string

Returns:

capitalized string

camelize

public static String camelize(String s)

Convert SOME_STUFF to SomeStuff

Parameters:

s - input string

Returns:

camelized string