Functions (Apache Standard Taglib 1.2.1 API)

java.lang.Object
- org.apache.taglibs.standard.functions.Functions

```
public class Functions
extends Object
```
Static functions that extend the Expression Language with standardized behaviour commonly used by page authors.
Implementation Note: When passing a String parameter, section 1.18.2 of the EL specification requires the container to coerce a null value to an empty string. These implementation assume such behaviour and do not check for null parameters. Passing a null will generally trigger a NullPointerException.

Author:

Pierre Delisle

Constructor Summary

Constructors
Constructor and Description

Functions()

Constructors
Constructor and Description
`Functions()`

Method Summary

Methods
Modifier and Type	Method and Description
`static boolean`	`contains(String input, String substring)` Tests if a string contains the specified substring.
`static boolean`	`containsIgnoreCase(String input, String substring)` Tests if a string contains the specified substring in a case insensitive way.
`static boolean`	`endsWith(String input, String suffix)` Tests if a string ends with the specified suffix according to the semantics of `String#endsWith()`.
`static String`	`escapeXml(String input)` Escapes characters that could be interpreted as XML markup as defined by the `<c:out> action.`
`static int`	`indexOf(String input, String substring)` Returns the index (0-based) withing a string of the first occurrence of a specified substring according to the semantics of the method `String#indexOf()`.
`static String`	`join(String[] array, String separator)` Joins all elements of an array into a string.
`static int`	`length(Object obj)` Returns the number of items in a collection or the number of characters in a string.
`static String`	`replace(String input, String before, String after)` Returns a string resulting from replacing all occurrences of a "before" substring with an "after" substring.
`static String[]`	`split(String input, String delimiters)` Splits a string into an array of substrings according to the semantics of `StringTokenizer`.
`static boolean`	`startsWith(String input, String prefix)` Tests if a string starts with the specified prefix according to the semantics of `String#startsWith()`.
`static String`	`substring(String input, int beginIndex, int endIndex)` Returns a subset of a string according to the semantics of `String#substring()` with additional semantics as follows: if `beginIndex < 0` its value is adjusted to 0 if `endIndex < 0 or greater than the string length`, its value is adjusted to the length of the string if `endIndex < beginIndex`, an empty string is returned
`static String`	`substringAfter(String input, String substring)` Returns a subset of a string following the first occurrence of a specific substring.
`static String`	`substringBefore(String input, String substring)` Returns a subset of a string immediately before the first occurrence of a specific substring.
`static String`	`toLowerCase(String input)` Converts all of the characters of the input string to lower case according to the semantics of method `String#toLowerCase()`.
`static String`	`toUpperCase(String input)` Converts all of the characters of the input string to upper case according to the semantics of method `String#toUpperCase()`.
`static String`	`trim(String input)` removes whitespace from both ends of a string according to the semantics of `String#trim()`.

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

- Constructor Detail
  - Functions
```
public Functions()
```
- Method Detail
  - toUpperCase
```
public static String toUpperCase(String input)
```
    Converts all of the characters of the input string to upper case according to the semantics of method String#toUpperCase().
    
    Parameters:
    input - the input string on which the transformation to upper case is applied
    
    Returns:
    the input string transformed to upper case
  - toLowerCase
```
public static String toLowerCase(String input)
```
    Converts all of the characters of the input string to lower case according to the semantics of method String#toLowerCase().
    
    Parameters:
    input - the input string on which the transformation to lower case is applied
    
    Returns:
    the input string transformed to lower case
  - indexOf
```
public static int indexOf(String input,
          String substring)
```
    Returns the index (0-based) withing a string of the first occurrence of a specified substring according to the semantics of the method String#indexOf().
    If substring is empty, this matches the beginning of the string and the value returned is 0.
    
    Parameters:
    input - the input string on which the function is applied
    substring - the substring to search for in the input string
    
    Returns:
    the 0-based index of the first matching substring, or -1 if it does not occur
  - contains
```
public static boolean contains(String input,
               String substring)
```
    Tests if a string contains the specified substring.
    
    Parameters:
    input - the input string on which the function is applied
    substring - the substring tested for
    
    Returns:
    true if the character sequence represented by the substring exists in the string
  - containsIgnoreCase
```
public static boolean containsIgnoreCase(String input,
                         String substring)
```
    Tests if a string contains the specified substring in a case insensitive way. Equivalent to fn:contains(fn:toUpperCase(string), fn:toUpperCase(substring)).
    
    Parameters:
    input - the input string on which the function is applied
    substring - the substring tested for
    
    Returns:
    true if the character sequence represented by the substring exists in the string
  - startsWith
```
public static boolean startsWith(String input,
                 String prefix)
```
    Tests if a string starts with the specified prefix according to the semantics of String#startsWith().
    
    Parameters:
    input - the input string on which the function is applied
    prefix - the prefix to be matched
    
    Returns:
    true if the input string starts with the prefix
  - endsWith
```
public static boolean endsWith(String input,
               String suffix)
```
    Tests if a string ends with the specified suffix according to the semantics of String#endsWith().
    
    Parameters:
    input - the input string on which the function is applied
    suffix - the suffix to be matched
    
    Returns:
    true if the input string ends with the suffix
  - substring
```
public static String substring(String input,
               int beginIndex,
               int endIndex)
```
    Returns a subset of a string according to the semantics of String#substring() with additional semantics as follows:
    - if beginIndex < 0 its value is adjusted to 0
    - if endIndex < 0 or greater than the string length, its value is adjusted to the length of the string
    - if endIndex < beginIndex, an empty string is returned
    Parameters:
    input - the input string on which the substring function is applied
    beginIndex - the beginning index (0-based), inclusive
    endIndex - the end index (0-based), exclusive
    
    Returns:
    a subset of string
  - substringAfter
```
public static String substringAfter(String input,
                    String substring)
```
    Returns a subset of a string following the first occurrence of a specific substring.
    If the substring is empty, it matches the beginning of the input string and the entire input string is returned. If the substring does not occur, an empty string is returned.
    
    Parameters:
    input - the input string on which the substring function is applied
    substring - the substring that delimits the beginning of the subset of the input string to be returned
    
    Returns:
    a substring of the input string that starts at the first character after the specified substring
  - substringBefore
```
public static String substringBefore(String input,
                     String substring)
```
    Returns a subset of a string immediately before the first occurrence of a specific substring.
    If the substring is empty, it matches the beginning of the input string and an empty string is returned. If the substring does not occur, an empty string is returned.
    
    Parameters:
    input - the input string on which the substring function is applied
    substring - the substring that delimits the beginning of the subset of the input string to be returned
    
    Returns:
    a substring of the input string that starts at the first character after the specified substring
  - escapeXml
```
public static String escapeXml(String input)
```
    Escapes characters that could be interpreted as XML markup as defined by the <c:out> action.
    Parameters: input - the string to escape Returns: escaped string
  trim public static String trim(String input) removes whitespace from both ends of a string according to the semantics of String#trim(). Parameters: input - the input string to be trimmed Returns: the trimmed string replace public static String replace(String input, String before, String after) Returns a string resulting from replacing all occurrences of a "before" substring with an "after" substring. The string is processed once and not reprocessed for further replacements. Parameters: input - the string on which the replacement is to be applied before - the substring to replace after - the replacement substring Returns: a string with before replaced with after split public static String[] split(String input, String delimiters) Splits a string into an array of substrings according to the semantics of StringTokenizer. If the input string is empty, a single element array containing an empty string is returned. If the delimiters are empty, a single element array containing the input string is returned. Parameters: input - the string to split delimiters - characters used to split the string Returns: an array of strings join public static String join(String[] array, String separator) Joins all elements of an array into a string. Implementation Note: The specification does not define what happens when elements in the array are null. For compatibility with previous implementations, the string "null" is used although EL conventions would suggest an empty string might be better. Parameters: array - an array of strings to be joined separator - used to separate the joined strings Returns: all array elements joined into one string with the specified separator length public static int length(Object obj) throws javax.servlet.jsp.JspTagException Returns the number of items in a collection or the number of characters in a string. The collection can be of any type supported for the items attribute of the <c:forEach> action. Parameters: obj - the collection or string whose length should be computed Returns: the length of the collection or string; 0 if obj is null Throws: javax.servlet.jsp.JspTagException - if the type is not valid

Class Functions

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Functions

Method Detail

toUpperCase

toLowerCase

indexOf

contains

containsIgnoreCase

startsWith

endsWith

substring

substringAfter

substringBefore

escapeXml

trim

replace

split

join

length