Strings (Wicket Parent 8.15.0-SNAPSHOT API)

java.lang.Object
- org.apache.wicket.util.string.Strings

```
public final class Strings
extends Object
```
A variety of static String utility methods.
The escapeMarkup() and toMultilineMarkup() methods are useful for turning normal Java Strings into HTML strings.
The lastPathComponent(), firstPathComponent(), afterFirstPathComponent() and beforeLastPathComponent() methods can chop up a String into path components using a separator character. If the separator cannot be found the original String is returned.
Similarly, the beforeLast(), beforeFirst(), afterFirst() and afterLast() methods return sections before and after a separator character. But if the separator cannot be found, an empty string is returned.
Some other miscellaneous methods will strip a given ending off a String if it can be found (stripEnding()), replace all occurrences of one String with another (replaceAll), do type conversions (toBoolean(), toChar(), toString()), check a String for emptiness (isEmpty()), convert a Throwable to a String (toString(Throwable)) or capitalize a String (capitalize()).

Author:

Jonathan Locke

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`LINE_SEPARATOR` The line separator for the current platform.
`static String`	`SESSION_ID_PARAM_NAME` The name of the parameter used to keep the session id.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static String`	`afterFirst(String s, char c)` Returns everything after the first occurrence of the given character in s.
`static String`	`afterFirstPathComponent(String path, char separator)` Gets everything after the first path component of a path using a given separator.
`static String`	`afterLast(String s, char c)` Returns everything after the last occurrence of the given character in s.
`static String`	`beforeFirst(String s, char c)` Returns everything before the first occurrence of the given character in s.
`static String`	`beforeLast(String s, char c)` Returns everything before the last occurrence of the given character in s.
`static String`	`beforeLastPathComponent(String path, char separator)` Gets everything before the last path component of a path using a given separator.
`static String`	`capitalize(String s)` Capitalizes a string.
`static String`	`defaultIfEmpty(String originalString, String defaultValue)` Returns the original string if this one is not empty (i.e.
`static CharSequence`	`escapeMarkup(CharSequence s)` Converts a Java String to an HTML markup string, but does not convert normal spaces to non-breaking space entities (<nbsp>).
`static CharSequence`	`escapeMarkup(CharSequence s, boolean escapeSpaces)` Converts a Java String to an HTML markup String by replacing illegal characters with HTML entities where appropriate.
`static CharSequence`	`escapeMarkup(CharSequence s, boolean escapeSpaces, boolean convertToHtmlUnicodeEscapes)` Converts a Java String to an HTML markup String by replacing illegal characters with HTML entities where appropriate.
`static String`	`firstPathComponent(String path, char separator)` Gets the first path component of a path using a given separator.
`static String`	`fromEscapedUnicode(String escapedUnicodeString)` Converts encoded \uxxxx to unicode chars and changes special saved chars to their original forms.
`static int`	`getLevenshteinDistance(CharSequence s, CharSequence t)` Find the Levenshtein distance between two Strings.
`static int`	`indexOf(CharSequence sequence, char ch)` returns the zero-based index of a character within a char sequence.
`static boolean`	`isEmpty(CharSequence string)` Checks whether the `string` is considered empty.
`static boolean`	`isEqual(String string1, String string2)` Checks whether two strings are equals taken care of 'null' values and treating 'null' same as trim(string).equals("")
`static boolean`	`isTrue(String s)` Converts the text in `s` to a corresponding boolean.
`static String`	`join(String separator, List<String> fragments)` Joins string fragments using the specified separator
`static String`	`join(String separator, String... fragments)` Joins string fragments using the specified separator
`static String`	`lastPathComponent(String path, char separator)` Gets the last path component of a path using a given separator.
`static int`	`lengthInBytes(String string, Charset charset)` Calculates the length of string in bytes, uses specified `charset` if provided.
`static CharSequence`	`replaceAll(CharSequence s, CharSequence searchFor, CharSequence replaceWith)` Replace all occurrences of one string replaceWith another string.
`static String`	`replaceHtmlEscapeNumber(String str)` Replace HTML numbers like 值 by the appropriate character.
`static String[]`	`split(String s, char c)` Simpler, faster version of String.split() for splitting on a simple character.
`static boolean`	`startsWith(String str, String prefix, boolean caseSensitive)` Extended `String.startsWith(String)` with support for case sensitivity
`static String`	`stripEnding(String s, String ending)` Strips the ending from the string `s`.
`static String`	`stripJSessionId(String url)` Strip any jsessionid and possibly other redundant info that might be in our way.
`static Boolean`	`toBoolean(String s)` Converts the string s to a Boolean.
`static char`	`toChar(String s)` Converts the 1 character string s to a character.
`static <T extends Enum<T>> T`	`toEnum(CharSequence value, Class<T> enumClass)` Return this value as en enum value.
`static String`	`toEscapedUnicode(String unicodeString)` Converts unicodes to encoded \uxxxx.
`static String`	`toHexString(byte[] bytes)` convert byte array to hex string
`static CharSequence`	`toMultilineMarkup(CharSequence s)` Converts a String to multiline HTML markup by replacing newlines with line break entities (<br/>) and multiple occurrences of newline with paragraph break entities (<p>).
`static String`	`toString(Object object)` Converts the given object to a string.
`static String`	`toString(Throwable throwable)` Converts a Throwable to a string.
`static CharSequence`	`unescapeMarkup(String markup)` Unescapes the escaped entities in the `markup` passed.

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

- Field Detail
  - LINE_SEPARATOR
```
public static final String LINE_SEPARATOR
```
    The line separator for the current platform.
  - SESSION_ID_PARAM_NAME
```
public static final String SESSION_ID_PARAM_NAME
```
    The name of the parameter used to keep the session id. The Servlet specification mandates jsessionid but the web containers provide ways to set a custom one, e.g. sid. Since Wicket doesn't have access to the web container internals the name should be set explicitly.
- Method Detail
  - afterFirst
```
public static String afterFirst(String s,
                                char c)
```
    Returns everything after the first occurrence of the given character in s.
    
    Parameters:
    
    s - The string
    
    c - The character
    
    Returns:
    
    Everything after the first occurrence of the given character in s. If the character cannot be found, an empty string is returned.
  - afterFirstPathComponent
```
public static String afterFirstPathComponent(String path,
                                             char separator)
```
    Gets everything after the first path component of a path using a given separator. If the separator cannot be found, an empty String is returned.
    For example, afterFirstPathComponent("foo:bar:baz", ':') would return "bar:baz" and afterFirstPathComponent("foo", ':') would return "".
    
    Parameters:
    
    path - The path to parse
    
    separator - The path separator character
    
    Returns:
    
    Everything after the first component in the path
  - afterLast
```
public static String afterLast(String s,
                               char c)
```
    Returns everything after the last occurrence of the given character in s.
    
    Parameters:
    
    s - The string
    
    c - The character
    
    Returns:
    
    Everything after the last occurrence of the given character in s. If the character cannot be found, an empty string is returned.
  - beforeFirst
```
public static String beforeFirst(String s,
                                 char c)
```
    Returns everything before the first occurrence of the given character in s.
    
    Parameters:
    
    s - The string
    
    c - The character
    
    Returns:
    
    Everything before the first occurrence of the given character in s. If the character cannot be found, an empty string is returned.
  - beforeLast
```
public static String beforeLast(String s,
                                char c)
```
    Returns everything before the last occurrence of the given character in s.
    
    Parameters:
    
    s - The string
    
    c - The character
    
    Returns:
    
    Everything before the last occurrence of the given character in s. If the character cannot be found, an empty string is returned.
  - beforeLastPathComponent
```
public static String beforeLastPathComponent(String path,
                                             char separator)
```
    Gets everything before the last path component of a path using a given separator. If the separator cannot be found, the path itself is returned.
    For example, beforeLastPathComponent("foo.bar.baz", '.') would return "foo.bar" and beforeLastPathComponent("foo", '.') would return "".
    
    Parameters:
    
    path - The path to parse
    
    separator - The path separator character
    
    Returns:
    
    Everything before the last component in the path
  - capitalize
```
public static String capitalize(String s)
```
    Capitalizes a string.
    
    Parameters:
    
    s - The string
    
    Returns:
    
    The capitalized string
  - escapeMarkup
```
public static CharSequence escapeMarkup(CharSequence s)
```
    Converts a Java String to an HTML markup string, but does not convert normal spaces to non-breaking space entities (<nbsp>).
    
    Parameters:
    
    s - The characters to escape
    
    Returns:
    
    The escaped string
    
    See Also:
    
    escapeMarkup(CharSequence, boolean)
  - escapeMarkup
```
public static CharSequence escapeMarkup(CharSequence s,
                                        boolean escapeSpaces)
```
    Converts a Java String to an HTML markup String by replacing illegal characters with HTML entities where appropriate. Spaces are converted to non-breaking spaces (<nbsp>) if escapeSpaces is true, tabs are converted to four non-breaking spaces, less than signs are converted to < entities and greater than signs to > entities.
    
    Parameters:
    
    s - The characters to escape
    
    escapeSpaces - True to replace ' ' with nonbreaking space
    
    Returns:
    
    The escaped string
  - escapeMarkup
```
public static CharSequence escapeMarkup(CharSequence s,
                                        boolean escapeSpaces,
                                        boolean convertToHtmlUnicodeEscapes)
```
    Converts a Java String to an HTML markup String by replacing illegal characters with HTML entities where appropriate. Spaces are converted to non-breaking spaces (<nbsp>) if escapeSpaces is true, tabs are converted to four non-breaking spaces, less than signs are converted to < entities and greater than signs to > entities.
    
    Parameters:
    
    s - The characters to escape
    
    escapeSpaces - True to replace ' ' with nonbreaking space
    
    convertToHtmlUnicodeEscapes - True to convert non-7 bit characters to unicode HTML (&#...)
    
    Returns:
    
    The escaped string
  - unescapeMarkup
```
public static CharSequence unescapeMarkup(String markup)
```
    Unescapes the escaped entities in the markup passed.
    
    Parameters:
    
    markup - The source String to unescape.
    
    Returns:
    
    the unescaped markup or null if the input is null
  firstPathComponent public static String firstPathComponent(String path, char separator) Gets the first path component of a path using a given separator. If the separator cannot be found, the path itself is returned. For example, firstPathComponent("foo.bar", '.') would return "foo" and firstPathComponent("foo", '.') would return "foo". Parameters: path - The path to parse separator - The path separator character Returns: The first component in the path or path itself if no separator characters exist. fromEscapedUnicode public static String fromEscapedUnicode(String escapedUnicodeString) Converts encoded \uxxxx to unicode chars and changes special saved chars to their original forms. Parameters: escapedUnicodeString - escaped unicode string, like '你好'. Returns: The actual unicode. Can be used for instance with message bundles isEmpty public static boolean isEmpty(CharSequence string) Checks whether the string is considered empty. Empty means that the string may contain whitespace, but no visible characters. "\n\t " is considered empty, while " a" is not. Parameters: string - The string Returns: True if the string is null or "" isEqual public static boolean isEqual(String string1, String string2) Checks whether two strings are equals taken care of 'null' values and treating 'null' same as trim(string).equals("") Parameters: string1 - string2 - Returns: true, if both strings are equal isTrue public static boolean isTrue(String s) throws StringValueConversionException Converts the text in s to a corresponding boolean. On, yes, y, true and 1 are converted to true. Off, no, n, false and 0 (zero) are converted to false. An empty string is converted to false. Conversion is case-insensitive, and does not take internationalization into account. 'Ja', 'Oui', 'Igen', 'Nein', 'Nee', 'Non', 'Nem' are all illegal values. Parameters: s - the value to convert into a boolean Returns: Boolean the converted value of s Throws: StringValueConversionException - when the value of s is not recognized. join public static String join(String separator, List<String> fragments) Joins string fragments using the specified separator Parameters: separator - fragments - Returns: combined fragments join public static String join(String separator, String... fragments) Joins string fragments using the specified separator Parameters: separator - fragments - Returns: combined fragments lastPathComponent public static String lastPathComponent(String path, char separator) Gets the last path component of a path using a given separator. If the separator cannot be found, the path itself is returned. For example, lastPathComponent("foo.bar", '.') would return "bar" and lastPathComponent("foo", '.') would return "foo". Parameters: path - The path to parse separator - The path separator character Returns: The last component in the path or path itself if no separator characters exist. replaceAll public static CharSequence replaceAll(CharSequence s, CharSequence searchFor, CharSequence replaceWith) Replace all occurrences of one string replaceWith another string. Parameters: s - The string to process searchFor - The value to search for replaceWith - The value to searchFor replaceWith Returns: The resulting string with searchFor replaced with replaceWith replaceHtmlEscapeNumber public static String replaceHtmlEscapeNumber(String str) Replace HTML numbers like 值 by the appropriate character. Parameters: str - The text to be evaluated Returns: The text with "numbers" replaced split public static String[] split(String s, char c) Simpler, faster version of String.split() for splitting on a simple character. Parameters: s - The string to split c - The character to split on Returns: The array of strings stripEnding public static String stripEnding(String s, String ending) Strips the ending from the string s. Parameters: s - The string to strip ending - The ending to strip off Returns: The stripped string or the original string if the ending did not exist stripJSessionId public static String stripJSessionId(String url) Strip any jsessionid and possibly other redundant info that might be in our way. Parameters: url - The url to strip Returns: The stripped url toBoolean public static Boolean toBoolean(String s) throws StringValueConversionException Converts the string s to a Boolean. See isTrue for valid values of s. Parameters: s - The string to convert. Returns: Boolean TRUE when isTrue(s). Throws: StringValueConversionException - when s is not a valid value See Also: isTrue(String) toChar public static char toChar(String s) throws StringValueConversionException Converts the 1 character string s to a character. Parameters: s - The 1 character string to convert to a char. Returns: Character value to convert Throws: StringValueConversionException - when the string is longer or shorter than 1 character, or null. toEscapedUnicode public static String toEscapedUnicode(String unicodeString) Converts unicodes to encoded \uxxxx. Parameters: unicodeString - The unicode string Returns: The escaped unicode string, like '你好'. toMultilineMarkup public static CharSequence toMultilineMarkup(CharSequence s) Converts a String to multiline HTML markup by replacing newlines with line break entities (<br/>) and multiple occurrences of newline with paragraph break entities (<p>). Parameters: s - String to transform Returns: String with all single occurrences of newline replaced with <br/> and all multiple occurrences of newline replaced with <p>. toString public static String toString(Object object) Converts the given object to a string. Does special conversion for throwables and String arrays of length 1 (in which case it just returns to string in that array, as this is a common thing to have in the Servlet API). Parameters: object - The object Returns: The string toString public static String toString(Throwable throwable) Converts a Throwable to a string. Parameters: throwable - The throwable Returns: The string lengthInBytes public static int lengthInBytes(String string, Charset charset) Calculates the length of string in bytes, uses specified charset if provided. Parameters: string - charset - (optional) character set to use when converting string to bytes Returns: length of string in bytes startsWith public static boolean startsWith(String str, String prefix, boolean caseSensitive) Extended String.startsWith(String) with support for case sensitivity Parameters: str - prefix - caseSensitive - Returns: true if str starts with prefix indexOf public static int indexOf(CharSequence sequence, char ch) returns the zero-based index of a character within a char sequence. this method mainly exists as an faster alternative for sequence.toString().indexOf(ch). Parameters: sequence - character sequence ch - character to search for Returns: index of character within character sequence or -1 if not found getLevenshteinDistance public static int getLevenshteinDistance(CharSequence s, CharSequence t) Find the Levenshtein distance between two Strings. This is the number of changes needed to change one String into another, where each change is a single character modification (deletion, insertion or substitution). The previous implementation of the Levenshtein distance algorithm was from http://www.merriampark.com/ld.htm Chas Emerick has written an implementation in Java, which avoids an OutOfMemoryError which can occur when my Java implementation is used with very large strings. This implementation of the Levenshtein distance algorithm is from http://www.merriampark.com/ldjava.htm Strings.getLevenshteinDistance(null, *) = IllegalArgumentException Strings.getLevenshteinDistance(*, null) = IllegalArgumentException Strings.getLevenshteinDistance("","") = 0 Strings.getLevenshteinDistance("","a") = 1 Strings.getLevenshteinDistance("aaapppp", "") = 7 Strings.getLevenshteinDistance("frog", "fog") = 1 Strings.getLevenshteinDistance("fly", "ant") = 3 Strings.getLevenshteinDistance("elephant", "hippo") = 7 Strings.getLevenshteinDistance("hippo", "elephant") = 7 Strings.getLevenshteinDistance("hippo", "zzzzzzzz") = 8 Strings.getLevenshteinDistance("hello", "hallo") = 1 Copied from Apache commons-lang StringUtils 3.0 Parameters: s - the first String, must not be null t - the second String, must not be null Returns: result distance Throws: IllegalArgumentException - if either String input null toHexString public static String toHexString(byte[] bytes) convert byte array to hex string Parameters: bytes - bytes to convert to hexadecimal representation Returns: hex string toEnum public static <T extends Enum<T>> T toEnum(CharSequence value, Class<T> enumClass) Return this value as en enum value. Parameters: value - the value to convert to an enum value enumClass - the enum type Returns: an enum value defaultIfEmpty public static String defaultIfEmpty(String originalString, String defaultValue) Returns the original string if this one is not empty (i.e. isEmpty(CharSequence) returns false), otherwise the default one is returned. The default string might be itself an empty one. Parameters: originalString - the original sting value defaultValue - the default string to return if the original is empty Returns: the original string value if not empty, the default one otherwise

Class Strings

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LINE_SEPARATOR

SESSION_ID_PARAM_NAME

Method Detail

afterFirst

afterFirstPathComponent

afterLast

beforeFirst

beforeLast

beforeLastPathComponent

capitalize

escapeMarkup

escapeMarkup

escapeMarkup

unescapeMarkup

firstPathComponent

fromEscapedUnicode

isEmpty

isEqual

isTrue

join

join

lastPathComponent

replaceAll

replaceHtmlEscapeNumber

split

stripEnding

stripJSessionId

toBoolean

toChar

toEscapedUnicode

toMultilineMarkup

toString

toString

lengthInBytes

startsWith

indexOf

getLevenshteinDistance

toHexString

toEnum

defaultIfEmpty