de.aristaflow.adept2.util

Class StringTools

java.lang.Object

de.aristaflow.adept2.util.StringTools

public final class StringTools
extends java.lang.Object

This class provides some useful string-related tool methods. The focus is on the ability to write short and simple code rather than on efficiency. This should be considered when using the methods to process large amounts of strings.

Author:

Patrick Schmidt

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StringTools.NullableStringComparator A comparator for strings including null.

Method Summary

Modifier and Type	Method and Description
static java.lang.String	defaultIfEmpty(java.lang.String s, java.lang.String defaultValue) Returns s if it has value (not null and not the empty string), else returns defaultValue.
static java.lang.String	emptyToNull(java.lang.String string) Returns null instead of the empty string; otherwise the given string is returned.
static boolean	equal(java.lang.String str1, java.lang.Object str2) Returns whether two strings are equal.
static java.lang.String	fromByteArray(byte[] bytes, java.lang.String encoding) Decodes the given byte array to a string using the specified encoding.
static boolean	hasValue(java.lang.String s) Returns true, if the given String s actually has a value set, ie. it is not null and not an empty String.
static java.lang.String	intern(java.lang.String s) Interns the designated string if we it is not null.
static java.lang.String	join(java.lang.String glue, java.util.Collection<java.lang.String> tokens) Does the opposite of String.split(String).
static java.lang.String	join(java.lang.String glue, java.lang.Object... tokens) Does the opposite of String.split(String).
static java.lang.String	join(java.lang.String glue, java.lang.String... tokens) Does the opposite of String.split(String).
static java.lang.String[]	join(java.lang.String glue, java.lang.String[]... tokens) This method is equal to join(String, String...) except that it works on arrays of strings and not individual strings.
static java.lang.String	lpad(java.lang.String string, int length) Returns the given string padded with spaces on the left up the given length.
static java.lang.String	lpad(java.lang.String string, int length, java.lang.String padString) Returns the given string padded with characters from the specified pad string on the left up the given length.
static java.lang.String	ltrim(java.lang.String string) Removes all whitespace (as defined in Character.isWhitespace(char)) from the left side of the given string.
static java.lang.String	ltrim(java.lang.String string, java.lang.String trimChars) Removes all characters defined in trimChars from the left side of the given string.
static java.lang.String	nullToEmpty(java.lang.String string) Returns the empty string instead of null; otherwise the given string is returned.
static java.lang.String	pad(java.lang.String string, int length) Returns the given string padded with spaces equally on both sides up the given length.
static java.lang.String	pad(java.lang.String string, int length, java.lang.String padString) Returns the given string padded with characters from the specified pad string equally on both sides up the given length.
static java.util.List<java.lang.String>	prefix(java.lang.String prefix, java.util.List<java.lang.String> strings) Prepends the given prefix to each string and returns them in a new list.
static java.lang.String[]	prefix(java.lang.String prefix, java.lang.String... strings) Prepends the given prefix to each string and returns them in a new array.
static java.lang.String	repeat(java.lang.String string, int times) Returns a string representing the specified string repeated the specified number of times.
static java.lang.String	repeat(java.lang.String string, java.lang.String glue, int times) Returns a string representing the specified string repeated the specified number of times.
static java.lang.String	replaceTabsAndNewlines(java.lang.String string, java.lang.String replacement) Replace all tab and new line characters (\t, \r, \n, \r\n) from the designated string with the given replacement.
static java.lang.String	rpad(java.lang.String string, int length) Returns the given string padded with spaces on the right up the given length.
static java.lang.String	rpad(java.lang.String string, int length, java.lang.String padString) Returns the given string padded with characters from the specified pad string on the right up the given length.
static java.lang.String	rtrim(java.lang.String string) Removes all whitespace (as defined in Character.isWhitespace(char)) from the right side of the given string.
static java.lang.String	rtrim(java.lang.String string, java.lang.String trimChars) Removes all characters defined in trimChars from the right side of the given string.
static void	splitClasspath(java.util.List<java.lang.String> classPath) Splits each element of the designated list at ";".
static java.util.List<java.lang.String>	suffix(java.lang.String suffix, java.util.List<java.lang.String> strings) Appends the given suffix to each string and returns them in a new list.
static java.lang.String[]	suffix(java.lang.String suffix, java.lang.String... strings) Appends the given suffix to each string and returns them in a new array.
static java.util.List<java.lang.String>	surround(java.lang.String prefix, java.lang.String suffix, java.util.List<java.lang.String> strings) Surrounds the given strings with the specified prefix and suffix and returns them in a new list.
static java.lang.String[]	surround(java.lang.String prefix, java.lang.String suffix, java.lang.String... strings) Surrounds the given strings with the specified prefix and suffix and returns them in a new array.
static byte[]	toByteArray(java.lang.String string, java.lang.String encoding) Encodes the given string to a byte array using the specified encoding.
static java.lang.String[]	toLower(java.lang.String[] strings) Converts all strings in the given array to lower case and returns them in a new array.
static java.lang.String[]	toUpper(java.lang.String[] strings) Converts all strings in the given array to upper case and returns them in a new array.
static java.lang.String	trim(java.lang.String string) Removes all whitespace (as defined in Character.isWhitespace(char)) from both sides of the given string.
static java.lang.String	trim(java.lang.String string, java.lang.String trimChars) Removes all characters defined in trimChars from both sides of the given string.
static java.lang.String	trimToNull(java.lang.String string) Trims the designated string and if it is empty afterwards, null will be returned.
static java.lang.String	trunc(java.lang.String string, int length) Truncate the string on his right side to the given length if necessary.

Methods inherited from class java.lang.Object

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

Method Detail

nullToEmpty

public static java.lang.String nullToEmpty(java.lang.String string)

Returns the empty string instead of null; otherwise the given string is returned.

Parameters:

string - a string or null

Returns:

the empty string instead of null; otherwise the given string

emptyToNull

public static java.lang.String emptyToNull(java.lang.String string)

Returns null instead of the empty string; otherwise the given string is returned.

Parameters:

string - a string or null

Returns:

null instead of the empty string; otherwise the given string

trimToNull

public static java.lang.String trimToNull(java.lang.String string)

Trims the designated string and if it is empty afterwards, null will be returned. This will also apply if the designated string is null.

Parameters:

string - The string which to trim.

Returns:

The trimmed string or null if the string is null or empty after trimming.

equal

public static boolean equal(java.lang.String str1,
                            java.lang.Object str2)

Returns whether two strings are equal. This method can deal with null values which is it's real benefit.

Analogous to String.equals(Object) the right-hand parameter may be any object

Parameters:

str1 - a string or null

str2 - another string or null; analogous to String.equals(Object) the right-hand parameter may actually be any object

Returns:

whether both strings are equal or both are null

join

public static java.lang.String join(java.lang.String glue,
                                    java.lang.Object... tokens)

Does the opposite of String.split(String).

Parameters:

glue - the string to put in between each pair of joined tokens

tokens - the strings to be joined

Returns:

the joined string

join

public static java.lang.String join(java.lang.String glue,
                                    java.lang.String... tokens)

Does the opposite of String.split(String).

Parameters:

glue - the string to put in between each pair of joined tokens

tokens - the strings to be joined

Returns:

the joined string

join

public static java.lang.String join(java.lang.String glue,
                                    java.util.Collection<java.lang.String> tokens)

Does the opposite of String.split(String).

Parameters:

glue - the string to put in between each pair of joined tokens

tokens - the strings to be joined

Returns:

the joined string

join

public static java.lang.String[] join(java.lang.String glue,
                                      java.lang.String[]... tokens)

This method is equal to join(String, String...) except that it works on arrays of strings and not individual strings. So the first string of tokens[0] is joined with the first strings of tokens[1], tokens[2], ...; the second string of tokens[0] is joined with the second strings of tokens[1], tokens[2], ...; etc.;

Parameters:

glue - the string to put in between each pair of joined tokens

tokens - the arrays of tokens to be joined

Returns:

an array of the joined strings

prefix

public static java.lang.String[] prefix(java.lang.String prefix,
                                        java.lang.String... strings)

Prepends the given prefix to each string and returns them in a new array.

Parameters:

strings - the strings to be prefixed

prefix - the prefix

Returns:

a new array containing the prefixed strings

prefix

public static java.util.List<java.lang.String> prefix(java.lang.String prefix,
                                                      java.util.List<java.lang.String> strings)

Prepends the given prefix to each string and returns them in a new list.

Parameters:

strings - the strings to be prefixed

prefix - the prefix

Returns:

a new list containing the prefixed strings

suffix

public static java.lang.String[] suffix(java.lang.String suffix,
                                        java.lang.String... strings)

Appends the given suffix to each string and returns them in a new array.

Parameters:

strings - the strings to be suffixed

suffix - the suffix

Returns:

a new array containing the suffixed strings

suffix

public static java.util.List<java.lang.String> suffix(java.lang.String suffix,
                                                      java.util.List<java.lang.String> strings)

Appends the given suffix to each string and returns them in a new list.

Parameters:

strings - the strings to be suffixed

suffix - the suffix

Returns:

a new list containing the suffixed strings

surround

public static java.lang.String[] surround(java.lang.String prefix,
                                          java.lang.String suffix,
                                          java.lang.String... strings)

Surrounds the given strings with the specified prefix and suffix and returns them in a new array.

Parameters:

strings - the strings to be suffixed

prefix - the prefix

suffix - the suffix

Returns:

a new array containing the surrounded strings

surround

public static java.util.List<java.lang.String> surround(java.lang.String prefix,
                                                        java.lang.String suffix,
                                                        java.util.List<java.lang.String> strings)

Surrounds the given strings with the specified prefix and suffix and returns them in a new list.

Parameters:

strings - the strings to be suffixed

prefix - the prefix

suffix - the suffix

Returns:

a new list containing the surrounded strings

repeat

public static java.lang.String repeat(java.lang.String string,
                                      int times)

Returns a string representing the specified string repeated the specified number of times.

Parameters:

string - The string to be repeated (must not be null).

times - the times the string should be repeated

Returns:

a string representing the specified string repeated the specified number of times

repeat

public static java.lang.String repeat(java.lang.String string,
                                      java.lang.String glue,
                                      int times)

Returns a string representing the specified string repeated the specified number of times. Between each repetition the specified glue string is inserted.

Parameters:

string - The string to be repeated (must not be null).

glue - the string to appear between each repetition

times - the times the string should be repeated

Returns:

a string representing the specified string repeated the specified number of times

pad

public static java.lang.String pad(java.lang.String string,
                                   int length)

Returns the given string padded with spaces equally on both sides up the given length. If the given length is negative or the string already longer than the given length, the string itself is returned.

Parameters:

string - The string to be padded (may be null).

length - the desired length after padding

Returns:

The given string padded with spaces equally on both sides up the given length. This will be null if the designated string is null.

lpad

public static java.lang.String lpad(java.lang.String string,
                                    int length)

Returns the given string padded with spaces on the left up the given length. If the given length is negative or the string already longer than the given length, the string itself is returned.

Parameters:

string - The string to be padded (may be null).

length - the desired length after padding

Returns:

The given string padded with spaces on the left up the given length. This will be null if the designated string is null.

rpad

public static java.lang.String rpad(java.lang.String string,
                                    int length)

Returns the given string padded with spaces on the right up the given length. If the given length is negative or the string already longer than the given length, the string itself is returned.

Parameters:

string - The string to be padded (may be null).

length - the desired length after padding

Returns:

The given string padded with spaces on the right up the given length. This will be null if the designated string is null.

pad

public static java.lang.String pad(java.lang.String string,
                                   int length,
                                   java.lang.String padString)

Returns the given string padded with characters from the specified pad string equally on both sides up the given length. If the given length is negative or the string already longer than the given length, the string itself is returned.

Parameters:

string - The string to be padded (may be null).

length - the desired length after padding

padString - the string containing the characters used for padding

Returns:

The given string padded with characters from the specified pad string equally on both sides up the given length. This will be null if the designated string is null.

lpad

public static java.lang.String lpad(java.lang.String string,
                                    int length,
                                    java.lang.String padString)

Returns the given string padded with characters from the specified pad string on the left up the given length. If the given length is negative or the string already longer than the given length, the string itself is returned.

Parameters:

string - The string to be padded (may be null).

length - the desired length after padding

padString - the string containing the characters used for padding

Returns:

The given string padded with characters from the specified pad string on the left up the given length. This will be null if the designated string is null.

rpad

public static java.lang.String rpad(java.lang.String string,
                                    int length,
                                    java.lang.String padString)

Returns the given string padded with characters from the specified pad string on the right up the given length. If the given length is negative or the string already longer than the given length, the string itself is returned.

Parameters:

string - The string to be padded (may be null).

length - the desired length after padding

padString - the string containing the characters used for padding

Returns:

The given string padded with characters from the specified pad string on the right up the given length. This will be null if the designated string is null.

replaceTabsAndNewlines

public static java.lang.String replaceTabsAndNewlines(java.lang.String string,
                                                      java.lang.String replacement)

Replace all tab and new line characters (\t, \r, \n, \r\n) from the designated string with the given replacement.

Parameters:

string - The string to be changed (may be null).

replacement - The replacement that should be used for any tab and newline character.

Returns:

The string with all tabs and newlines replaced by the replacement string. This will be null if the designated string is null.

trim

public static java.lang.String trim(java.lang.String string)

Removes all whitespace (as defined in Character.isWhitespace(char)) from both sides of the given string.

Parameters:

string - The string to be trimmed (may be null).

Returns:

The trimmed string or null if the designated string is null.

ltrim

public static java.lang.String ltrim(java.lang.String string)

Removes all whitespace (as defined in Character.isWhitespace(char)) from the left side of the given string.

Parameters:

string - The string to be trimmed (may be null).

Returns:

The trimmed string or null if the designated string is null.

rtrim

public static java.lang.String rtrim(java.lang.String string)

Removes all whitespace (as defined in Character.isWhitespace(char)) from the right side of the given string.

Parameters:

string - The string to be trimmed (may be null).

Returns:

The trimmed string or null if the designated string is null.

trim

public static java.lang.String trim(java.lang.String string,
                                    java.lang.String trimChars)

Removes all characters defined in trimChars from both sides of the given string.

Parameters:

string - The string to be trimmed (may be null).

trimChars - the chars to be trimmed away from both sides of the string

Returns:

The trimmed string or null if the designated string is null.

ltrim

public static java.lang.String ltrim(java.lang.String string,
                                     java.lang.String trimChars)

Removes all characters defined in trimChars from the left side of the given string.

Parameters:

string - The string to be trimmed (may be null)

trimChars - the chars to be trimmed away from the left side of the string

Returns:

The trimmed string or null if the designated string is null.

rtrim

public static java.lang.String rtrim(java.lang.String string,
                                     java.lang.String trimChars)

Removes all characters defined in trimChars from the right side of the given string.

Parameters:

string - The string to be trimmed (may be null).

trimChars - the chars to be trimmed away from the right side of the string

Returns:

The trimmed string or null if the designated string is null.

trunc

public static java.lang.String trunc(java.lang.String string,
                                     int length)

Truncate the string on his right side to the given length if necessary. Otherwise the same string is returned.

Parameters:

string - The string to be truncated (may be null).

length - the desired length of the string

Returns:

The truncated string or null if the designated string is null.

toLower

public static java.lang.String[] toLower(java.lang.String[] strings)

Converts all strings in the given array to lower case and returns them in a new array.

Parameters:

strings -

Returns:

lower case versions of the given strings

See Also:

String.toLowerCase()

toUpper

public static java.lang.String[] toUpper(java.lang.String[] strings)

Converts all strings in the given array to upper case and returns them in a new array.

Parameters:

strings -

Returns:

upper case versions of the given strings

See Also:

String.toUpperCase()

toByteArray

public static byte[] toByteArray(java.lang.String string,
                                 java.lang.String encoding)
                          throws java.io.UnsupportedEncodingException

Encodes the given string to a byte array using the specified encoding.

Parameters:

string - the string to be encoded

encoding - the encoding to be used

Returns:

the string encoded in a byte array using the specified encoding

Throws:

java.io.UnsupportedEncodingException - if the specified encoding is not supported

fromByteArray

public static java.lang.String fromByteArray(byte[] bytes,
                                             java.lang.String encoding)
                                      throws java.io.UnsupportedEncodingException

Decodes the given byte array to a string using the specified encoding.

Parameters:

bytes - the byte array to be decoded

encoding - the encoding to be used

Returns:

the string decoded from the byte array using the specified encoding

Throws:

java.io.UnsupportedEncodingException - if the specified encoding is not supported

splitClasspath

public static void splitClasspath(java.util.List<java.lang.String> classPath)

Splits each element of the designated list at ";". This allows classpaths to be either separated by "," (the list delimiter for Apache Commons Configuration) or ";" (the normal classpath separator in AristaFlow.
The order is respected, that an element of the list having sub-elements leads to several additional list elements right after the corresponding element (depth-first).

Parameters:

classPath - The classpath as list to separate not yet separated classpaths.

hasValue

public static boolean hasValue(java.lang.String s)

Returns true, if the given String s actually has a value set, ie. it is not null and not an empty String.

Parameters:

s - The string to be checked.

Returns:

True if != null and != "".

defaultIfEmpty

public static java.lang.String defaultIfEmpty(java.lang.String s,
                                              java.lang.String defaultValue)

Returns s if it has value (not null and not the empty string), else returns defaultValue.

Parameters:

s - The string to checked for value and to be used if it has a value.

defaultValue - The string to be used, if s is null or empty.

Returns:

s if it has a value, else defaultValue

intern

public static java.lang.String intern(java.lang.String s)

Interns the designated string if we it is not null.

Parameters:

s - The string to intern or null.

Returns:

The interned string if interning is appropriate. Apparently, null will not be interned but just returned.