Class SubstringFunction

java.lang.Object
org.jaxen.function.SubstringFunction
All Implemented Interfaces:
Function

public class SubstringFunction extends Object implements Function

4.2 string substring(string,number,number?)

The substring function returns the substring of the first argument starting at the position specified in the second argument with length specified in the third argument. For example, substring("12345",2,3) returns "234". If the third argument is not specified, it returns the substring starting at the position specified in the second argument and continuing to the end of the string. For example, substring("12345",2) returns "2345".

More precisely, each character in the string (see [3.6 Strings]) is considered to have a numeric position: the position of the first character is 1, the position of the second character is 2 and so on.

NOTE: This differs from Java and ECMAScript, in which the String.substring method treats the position of the first character as 0.

The returned substring contains those characters for which the position of the character is greater than or equal to the rounded value of the second argument and, if the third argument is specified, less than the sum of the rounded value of the second argument and the rounded value of the third argument; the comparisons and addition used for the above follow the standard IEEE 754 rules; rounding is done as if by a call to the round function. The following examples illustrate various unusual cases:

  • substring("12345", 1.5, 2.6) returns "234"

  • substring("12345", 0, 3) returns "12"

  • substring("12345", 0 div 0, 3) returns ""

  • . substring("12345", 1, 0 div 0) returns ""

  • substring("12345", -42, 1 div 0) returns "12345"

substring("12345", -1 div 0, 1 div 0) returns ""
See Also:
  • Constructor Details

    • SubstringFunction

      public SubstringFunction()
      Create a new SubstringFunction object.
  • Method Details

    • call

      public Object call(Context context, List args) throws FunctionCallException
      Returns a substring of an XPath string-value by character index.
      Specified by:
      call in interface Function
      Parameters:
      context - the context at the point in the expression when the function is called
      args - a list that contains two or three items
      Returns:
      a String containing the specifed character subsequence of the original string or the string-value of the context node
      Throws:
      FunctionCallException - if args has more than three or less than two items
    • unicodeSubstring

      private static String unicodeSubstring(String s, int start, int end)