org.apache.flink.util

Class StringUtils

java.lang.Object

org.apache.flink.util.StringUtils

@PublicEvolving
public final class StringUtils
extends Object

Utility class to convert objects into strings in vice-versa.

Method Summary

Modifier and Type	Method and Description
static String	arrayAwareToString(Object o) This method calls Object.toString() on the given object, unless the object is an array.
static String	arrayToString(Object array) Returns a string representation of the given array.
static String	byteToHexString(byte[] bytes) Given an array of bytes it will convert the bytes to a hex string representation of the bytes.
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	escapeHtml(String str) Helper function to escape Strings for display in HTML pages.
static String	getRandomString(Random rnd, int minLength, int maxLength) Creates a random string with a length within the given interval.
static String	getRandomString(Random rnd, int minLength, int maxLength, char minValue, char maxValue) Creates a random string with a length within the given interval.
static byte[]	hexStringToByte(String hex) Given a hex string this will return the byte array corresponding to the string .
static String	readNullableString(DataInputView in) Reads a String from the given input.
static String	showControlCharacters(String str) Replaces control characters by their escape-coded version.
static String	stringifyException(Throwable e) Makes a string representation of the exception.
static void	writeNullableString(String str, DataOutputView out) Writes a String to the given output.

Methods inherited from class java.lang.Object

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

Method Detail

stringifyException

public static String stringifyException(Throwable e)

Makes a string representation of the exception.

Parameters:

e - the exception to stringify

Returns:

A string with exception name and call stack.

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 - the bytes to convert in a hex string

start - start index, inclusively

end - end index, exclusively

Returns:

hex string representation of the byte array

See Also:

org.apache.commons.codec.binary.Hex#encodeHexString(byte[])

byteToHexString

public static String byteToHexString(byte[] bytes)

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

Parameters:

bytes - the bytes to convert in a hex string

Returns:

hex string representation of the byte array

hexStringToByte

public static byte[] hexStringToByte(String hex)

Given a hex string 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

escapeHtml

public static String escapeHtml(String str)

Helper function to escape Strings for display in HTML pages. The function replaces certain characters by their HTML coded correspondent.

Parameters:

str - The string to escape.

Returns:

The escaped string.

arrayAwareToString

public static String arrayAwareToString(Object o)

This method calls Object.toString() on the given object, unless the object is an array. In that case, it will use the arrayToString(Object) method to create a string representation of the array that includes all contained elements.

Parameters:

o - The object for which to create the string representation.

Returns:

The string representation of the object.

arrayToString

public static String arrayToString(Object array)

Returns a string representation of the given array. This method takes an Object to allow also all types of primitive type arrays.

Parameters:

array - The array to create a string representation for.

Returns:

The string representation of the array.

Throws:

IllegalArgumentException - If the given object is no array.

showControlCharacters

public static String showControlCharacters(String str)

Replaces control characters by their escape-coded version. For example, if the string contains a line break character ('\n'), this character will be replaced by the two characters backslash '\' and 'n'. As a consequence, the resulting string will not contain any more control characters.

Parameters:

str - The string in which to replace the control characters.

Returns:

The string with the replaced characters.

getRandomString

public static String getRandomString(Random rnd,
                                     int minLength,
                                     int maxLength)

Creates a random string with a length within the given interval. The string contains only characters that can be represented as a single code point.

Parameters:

rnd - The random used to create the strings.

minLength - The minimum string length.

maxLength - The maximum string length (inclusive).

Returns:

A random String.

getRandomString

public static String getRandomString(Random rnd,
                                     int minLength,
                                     int maxLength,
                                     char minValue,
                                     char maxValue)

Creates a random string with a length within the given interval. The string contains only characters that can be represented as a single code point.

Parameters:

rnd - The random used to create the strings.

minLength - The minimum string length.

maxLength - The maximum string length (inclusive).

minValue - The minimum character value to occur.

maxValue - The maximum character value to occur.

Returns:

A random String.

writeNullableString

public static void writeNullableString(String str,
                                       DataOutputView out)
                                throws IOException

Writes a String to the given output. The string may be null. The written string can be read with readNullableString(DataInputView)-

Parameters:

str - The string to write, or null.

out - The output to write to.

Throws:

IOException - Throws if the writing or the serialization fails.

readNullableString

public static String readNullableString(DataInputView in)
                                 throws IOException

Reads a String from the given input. The string may be null and must have been written with writeNullableString(String, DataOutputView).

Parameters:

in - The input to read from.

Returns:

The deserialized string, or null.

Throws:

IOException - Throws if the reading or the deserialization fails.