java.lang.Object
- org.jivesoftware.smack.util.StringUtils

```
public class StringUtils
extends Object
```
A collection of utility methods for String objects.

Field Summary

Fields
Modifier and Type	Field	Description
`static String`	`AMP_ENCODE`
`static String`	`APOS_ENCODE`
`static String`	`GT_ENCODE`
`static char[]`	`HEX_CHARS`
`static String`	`LT_ENCODE`
`static String`	`MD5`
`static String`	`PORTABLE_NEWLINE_REGEX`
`static String`	`QUOTE_ENCODE`
`static String`	`SHA1`
`static String`	`UNAMBIGUOUS_NUMBERS_AND_LETTERS_STRING`	24 upper case characters from the latin alphabet and numbers without '0' and 'O'.
`static String`	`USASCII`	Deprecated. use StandardCharsets.US_ASCII instead.
`static String`	`UTF8`	Deprecated. use StandardCharsets.UTF_8 instead.

Constructor Summary

Constructors
Constructor Description

StringUtils()

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`static Appendable`	`appendHeading(Appendable appendable, String heading)`
`static Appendable`	`appendHeading(Appendable appendable, String heading, char underlineChar)`
`static void`	`appendTo(Collection<? extends Object> collection, StringBuilder sb)`
`static void`	`appendTo(Collection<? extends Object> collection, String delimiter, StringBuilder sb)`
`static <O> void`	`appendTo(Collection<O> collection, StringBuilder sb, Consumer<O> appendFunction)`
`static <O> void`	`appendTo(Collection<O> collection, String delimiter, StringBuilder sb, Consumer<O> appendFunction)`
`static String`	`collectionToString(Collection<? extends Object> collection)`	Transform a collection of objects to a whitespace delimited String.
`static String`	`deleteXmlWhitespace(String string)`
`static String`	`encodeHex(byte[] bytes)`	Encodes an array of bytes as String representation of hexadecimal.
`static CharSequence`	`escapeForXml(CharSequence input)`	Escape `input` for XML.
`static CharSequence`	`escapeForXmlAttribute(CharSequence input)`	Escape `input` for XML.
`static CharSequence`	`escapeForXmlAttributeApos(CharSequence input)`	Escape `input` for XML.
`static CharSequence`	`escapeForXmlText(CharSequence input)`	Escape `input` for XML.
`static String`	`hash(String data)`	Deprecated. use `SHA1.hex(String)` instead.
`static String`	`insecureRandomString(int length)`	Returns a random String of numbers and letters (lower and upper case) of the specified length.
`static boolean`	`isEmpty(CharSequence cs)`	Returns true if the given CharSequence is empty.
`static boolean`	`isNotEmpty(CharSequence cs)`	Returns true if CharSequence is not null and is not empty, false otherwise.
`static boolean`	`isNotEmpty(CharSequence... css)`	Returns true if all given CharSequences are not empty.
`static boolean`	`isNullOrEmpty(CharSequence cs)`	Returns true if the given CharSequence is null or empty.
`static boolean`	`isNullOrEmpty(CharSequence... css)`	Returns true if all given CharSequences are either null or empty.
`static boolean`	`isNullOrNotEmpty(CharSequence cs)`
`static String`	`maybeToString(CharSequence cs)`	Return the String representation of the given char sequence if it is not null.
`static int`	`nullSafeCharSequenceComparator(CharSequence csOne, CharSequence csTwo)`
`static boolean`	`nullSafeCharSequenceEquals(CharSequence csOne, CharSequence csTwo)`
`static String`	`randomString(int length)`
`static String`	`randomString(int length, Random random)`
`static <CS extends CharSequence> CS`	`requireNotNullNorEmpty(CS cs, String message)`	Require a `CharSequence` to be neither null, nor empty.
`static <CS extends CharSequence> CS`	`requireNotNullOrEmpty(CS cs, String message)`	Deprecated. use `requireNotNullNorEmpty(CharSequence, String)` instead.
`static <CS extends CharSequence> CS`	`requireNullOrNotEmpty(CS cs, String message)`
`static String`	`returnIfNotEmptyTrimmed(String string)`
`static String`	`secureOfflineAttackSafeRandomString()`	Generate a secure random string with is human readable.
`static String`	`secureOnlineAttackSafeRandomString()`
`static String`	`secureUniqueRandomString()`
`static List<String>`	`splitLinesPortable(String input)`
`static StringBuilder`	`toStringBuilder(Collection<? extends Object> collection, String delimiter)`	Transform a collection of objects to a delimited String.
`static List<String>`	`toStrings(Collection<? extends CharSequence> charSequences)`
`static byte[]`	`toUtf8Bytes(String string)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - MD5
```
public static final String MD5
```
    See Also:
    
    Constant Field Values
  - SHA1
```
public static final String SHA1
```
    See Also:
    
    Constant Field Values
  - UTF8
```
@Deprecated
public static final String UTF8
```
    Deprecated.
    use StandardCharsets.UTF_8 instead.
    
    Deprecated, do not use.
    
    See Also:
    
    Constant Field Values
  - USASCII
```
@Deprecated
public static final String USASCII
```
    Deprecated.
    use StandardCharsets.US_ASCII instead.
    
    Deprecated, do not use.
    
    See Also:
    
    Constant Field Values
  - QUOTE_ENCODE
```
public static final String QUOTE_ENCODE
```
    See Also:
    
    Constant Field Values
  - APOS_ENCODE
```
public static final String APOS_ENCODE
```
    See Also:
    
    Constant Field Values
  - AMP_ENCODE
```
public static final String AMP_ENCODE
```
    See Also:
    
    Constant Field Values
  - LT_ENCODE
```
public static final String LT_ENCODE
```
    See Also:
    
    Constant Field Values
  - GT_ENCODE
```
public static final String GT_ENCODE
```
    See Also:
    
    Constant Field Values
  - HEX_CHARS
```
public static final char[] HEX_CHARS
```
  - UNAMBIGUOUS_NUMBERS_AND_LETTERS_STRING
```
public static final String UNAMBIGUOUS_NUMBERS_AND_LETTERS_STRING
```
    24 upper case characters from the latin alphabet and numbers without '0' and 'O'.
    
    See Also:
    
    Constant Field Values
  - PORTABLE_NEWLINE_REGEX
```
public static final String PORTABLE_NEWLINE_REGEX
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - StringUtils
```
public StringUtils()
```
- Method Detail
  - escapeForXml
```
public static CharSequence escapeForXml(CharSequence input)
```
    Escape input for XML.
    
    Parameters:
    
    input - the input to escape.
    
    Returns:
    
    the XML escaped variant of input.
  - escapeForXmlAttribute
```
public static CharSequence escapeForXmlAttribute(CharSequence input)
```
    Escape input for XML.
    
    Parameters:
    
    input - the input to escape.
    
    Returns:
    
    the XML escaped variant of input.
    
    Since:
    
    4.2
  - escapeForXmlAttributeApos
```
public static CharSequence escapeForXmlAttributeApos(CharSequence input)
```
    Escape input for XML.
    This is an optimized variant of escapeForXmlAttribute(CharSequence) for XML where the XML attribute is quoted using ''' (Apos).
    
    Parameters:
    
    input - the input to escape.
    
    Returns:
    
    the XML escaped variant of input.
    
    Since:
    
    4.2
  - escapeForXmlText
```
public static CharSequence escapeForXmlText(CharSequence input)
```
    Escape input for XML.
    
    Parameters:
    
    input - the input to escape.
    
    Returns:
    
    the XML escaped variant of input.
    
    Since:
    
    4.2
  - hash
```
@Deprecated
public static String hash(String data)
```
    Deprecated.
    use SHA1.hex(String) instead.
    
    Hashes a String using the SHA-1 algorithm and returns the result as a String of hexadecimal numbers. This method is synchronized to avoid excessive MessageDigest object creation. If calling this method becomes a bottleneck in your code, you may wish to maintain a pool of MessageDigest objects instead of using this method.
    A hash is a one-way function -- that is, given an input, an output is easily computed. However, given the output, the input is almost impossible to compute. This is useful for passwords since we can store the hash and a hacker will then have a very hard time determining the original password.
    
    Parameters:
    
    data - the String to compute the hash of.
    
    Returns:
    
    a hashed version of the passed-in String
  - encodeHex
```
public static String encodeHex(byte[] bytes)
```
    Encodes an array of bytes as String representation of hexadecimal.
    
    Parameters:
    
    bytes - an array of bytes to convert to a hex string.
    
    Returns:
    
    generated hex string.
  - toUtf8Bytes
```
public static byte[] toUtf8Bytes(String string)
```
  - insecureRandomString
```
public static String insecureRandomString(int length)
```
    Returns a random String of numbers and letters (lower and upper case) of the specified length. The method uses the Random class that is built-in to Java which is suitable for low to medium grade security uses. This means that the output is only pseudo random, i.e., each number is mathematically generated so is not truly random.
    The specified length must be at least one. If not, the method will return null.
    
    Parameters:
    
    length - the desired length of the random String to return.
    
    Returns:
    
    a random String of numbers and letters of the specified length.
  - secureOnlineAttackSafeRandomString
```
public static String secureOnlineAttackSafeRandomString()
```
  - secureUniqueRandomString
```
public static String secureUniqueRandomString()
```
  - secureOfflineAttackSafeRandomString
```
public static String secureOfflineAttackSafeRandomString()
```
    Generate a secure random string with is human readable. The resulting string consists of 24 upper case characters from the Latin alphabet and numbers without '0' and 'O', grouped into 4-characters chunks, e.g. "TWNK-KD5Y-MT3T-E1GS-DRDB-KVTW". The characters are randomly selected by a cryptographically secure pseudorandom number generator (CSPRNG).
    The string can be used a backup "code" for secrets, and is in fact the same as the one backup code specified in XEP-0373 and the one used by the Backup Format v2 of OpenKeychain.
    
    Returns:
    
    a human readable secure random string.
    
    See Also:
    
    XEP-0373 §5.4 Encrypting the Secret Key Backup
  - randomString
```
public static String randomString(int length)
```
  - randomString
```
public static String randomString(int length,
                                  Random random)
```
  - isNotEmpty
```
public static boolean isNotEmpty(CharSequence cs)
```
    Returns true if CharSequence is not null and is not empty, false otherwise. Examples: isNotEmpty(null) - false isNotEmpty("") - false isNotEmpty(" ") - true isNotEmpty("empty") - true
    
    Parameters:
    
    cs - checked CharSequence
    
    Returns:
    
    true if string is not null and is not empty, false otherwise
  - isNullOrEmpty
```
public static boolean isNullOrEmpty(CharSequence cs)
```
    Returns true if the given CharSequence is null or empty.
    
    Parameters:
    
    cs - TODO javadoc me please
    
    Returns:
    
    true if the given CharSequence is null or empty
  - isNotEmpty
```
public static boolean isNotEmpty(CharSequence... css)
```
    Returns true if all given CharSequences are not empty.
    
    Parameters:
    
    css - the CharSequences to test.
    
    Returns:
    
    true if all given CharSequences are not empty.
  - isNullOrEmpty
```
public static boolean isNullOrEmpty(CharSequence... css)
```
    Returns true if all given CharSequences are either null or empty.
    
    Parameters:
    
    css - the CharSequences to test.
    
    Returns:
    
    true if all given CharSequences are null or empty.
  - isNullOrNotEmpty
```
public static boolean isNullOrNotEmpty(CharSequence cs)
```
  - isEmpty
```
public static boolean isEmpty(CharSequence cs)
```
    Returns true if the given CharSequence is empty.
    
    Parameters:
    
    cs - TODO javadoc me please
    
    Returns:
    
    true if the given CharSequence is empty
  - collectionToString
```
public static String collectionToString(Collection<? extends Object> collection)
```
    Transform a collection of objects to a whitespace delimited String.
    
    Parameters:
    
    collection - the collection to transform.
    
    Returns:
    
    a String with all the elements of the collection.
  - toStringBuilder
```
public static StringBuilder toStringBuilder(Collection<? extends Object> collection,
                                            String delimiter)
```
    Transform a collection of objects to a delimited String.
    
    Parameters:
    
    collection - the collection to transform.
    
    delimiter - the delimiter used to delimit the Strings.
    
    Returns:
    
    a StringBuilder with all the elements of the collection.
  - appendTo
```
public static void appendTo(Collection<? extends Object> collection,
                            StringBuilder sb)
```
  - appendTo
```
public static <O> void appendTo(Collection<O> collection,
                                StringBuilder sb,
                                Consumer<O> appendFunction)
```
  - appendTo
```
public static void appendTo(Collection<? extends Object> collection,
                            String delimiter,
                            StringBuilder sb)
```
  - appendTo
```
public static <O> void appendTo(Collection<O> collection,
                                String delimiter,
                                StringBuilder sb,
                                Consumer<O> appendFunction)
```
  - returnIfNotEmptyTrimmed
```
public static String returnIfNotEmptyTrimmed(String string)
```
  - nullSafeCharSequenceEquals
```
public static boolean nullSafeCharSequenceEquals(CharSequence csOne,
                                                 CharSequence csTwo)
```
  - nullSafeCharSequenceComparator
```
public static int nullSafeCharSequenceComparator(CharSequence csOne,
                                                 CharSequence csTwo)
```
  - requireNotNullOrEmpty
```
@Deprecated
public static <CS extends CharSequence> CS requireNotNullOrEmpty(CS cs,
                                                                 String message)
```
    Deprecated.
    use requireNotNullNorEmpty(CharSequence, String) instead.
    
    Require a CharSequence to be neither null, nor empty.
    
    Type Parameters:
    
    CS - CharSequence type
    
    Parameters:
    
    cs - CharSequence
    
    message - error message
    
    Returns:
    
    cs TODO javadoc me please
  - requireNotNullNorEmpty
```
public static <CS extends CharSequence> CS requireNotNullNorEmpty(CS cs,
                                                                  String message)
```
    Require a CharSequence to be neither null, nor empty.
    
    Type Parameters:
    
    CS - CharSequence type
    
    Parameters:
    
    cs - CharSequence
    
    message - error message
    
    Returns:
    
    cs TODO javadoc me please
  - requireNullOrNotEmpty
```
public static <CS extends CharSequence> CS requireNullOrNotEmpty(CS cs,
                                                                 String message)
```
  - maybeToString
```
public static String maybeToString(CharSequence cs)
```
    Return the String representation of the given char sequence if it is not null.
    
    Parameters:
    
    cs - the char sequence or null.
    
    Returns:
    
    the String representation of cs or null.
  - deleteXmlWhitespace
```
public static String deleteXmlWhitespace(String string)
```
  - appendHeading
```
public static Appendable appendHeading(Appendable appendable,
                                       String heading)
                                throws IOException
```
    Throws:
    
    IOException
  - appendHeading
```
public static Appendable appendHeading(Appendable appendable,
                                       String heading,
                                       char underlineChar)
                                throws IOException
```
    Throws:
    
    IOException
  - splitLinesPortable
```
public static List<String> splitLinesPortable(String input)
```
  - toStrings
```
public static List<String> toStrings(Collection<? extends CharSequence> charSequences)
```

Class StringUtils

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MD5

SHA1

UTF8

USASCII

QUOTE_ENCODE

APOS_ENCODE

AMP_ENCODE

LT_ENCODE

GT_ENCODE

HEX_CHARS

UNAMBIGUOUS_NUMBERS_AND_LETTERS_STRING

PORTABLE_NEWLINE_REGEX

Constructor Detail

StringUtils

Method Detail

escapeForXml

escapeForXmlAttribute

escapeForXmlAttributeApos

escapeForXmlText

hash

encodeHex

toUtf8Bytes

insecureRandomString

secureOnlineAttackSafeRandomString

secureUniqueRandomString

secureOfflineAttackSafeRandomString

randomString

randomString

isNotEmpty

isNullOrEmpty

isNotEmpty

isNullOrEmpty

isNullOrNotEmpty

isEmpty

collectionToString

toStringBuilder

appendTo

appendTo

appendTo

appendTo

returnIfNotEmptyTrimmed

nullSafeCharSequenceEquals

nullSafeCharSequenceComparator

requireNotNullOrEmpty

requireNotNullNorEmpty

requireNullOrNotEmpty

maybeToString

deleteXmlWhitespace

appendHeading

appendHeading

splitLinesPortable

toStrings