Class CharSetUtils


  • public class CharSetUtils
    extends Object

    Operations on CharSets.

    This class handles null input gracefully. An exception will not be thrown for a null input. Each method documents its behaviour in more detail.

    #ThreadSafe#

    Since:
    1.0
    Version:
    $Id: CharSetUtils.java 1057072 2011-01-10 01:55:57Z niallp $
    See Also:
    CharSet
    • Constructor Detail

      • CharSetUtils

        public CharSetUtils()

        CharSetUtils instances should NOT be constructed in standard programming. Instead, the class should be used as CharSetUtils.evaluateSet(null);.

        This constructor is public to permit tools that require a JavaBean instance to operate.

    • Method Detail

      • evaluateSet

        public static CharSet evaluateSet​(String[] set)
        Deprecated.
        Use CharSet.getInstance(String[]). Method will be removed in Commons Lang 3.0.

        Creates a CharSet instance which allows a certain amount of set logic to be performed.

        The syntax is:

        • "aeio" which implies 'a','e',..
        • "^e" implies not e.
        • "ej-m" implies e,j->m. e,j,k,l,m.
         CharSetUtils.evaluateSet(null)    = null
         CharSetUtils.evaluateSet([])      = CharSet matching nothing
         CharSetUtils.evaluateSet(["a-e"]) = CharSet matching a,b,c,d,e
         
        Parameters:
        set - the set, may be null
        Returns:
        a CharSet instance, null if null input
      • squeeze

        public static String squeeze​(String str,
                                     String set)

        Squeezes any repetitions of a character that is mentioned in the supplied set.

         CharSetUtils.squeeze(null, *)        = null
         CharSetUtils.squeeze("", *)          = ""
         CharSetUtils.squeeze(*, null)        = *
         CharSetUtils.squeeze(*, "")          = *
         CharSetUtils.squeeze("hello", "k-p") = "helo"
         CharSetUtils.squeeze("hello", "a-e") = "hello"
         
        Parameters:
        str - the string to squeeze, may be null
        set - the character set to use for manipulation, may be null
        Returns:
        modified String, null if null string input
        See Also:
        for set-syntax.
      • squeeze

        public static String squeeze​(String str,
                                     String[] set)

        Squeezes any repetitions of a character that is mentioned in the supplied set.

        An example is:

        • squeeze("hello", {"el"}) => "helo"
        Parameters:
        str - the string to squeeze, may be null
        set - the character set to use for manipulation, may be null
        Returns:
        modified String, null if null string input
        See Also:
        for set-syntax.
      • count

        public static int count​(String str,
                                String set)

        Takes an argument in set-syntax, see evaluateSet, and returns the number of characters present in the specified string.

         CharSetUtils.count(null, *)        = 0
         CharSetUtils.count("", *)          = 0
         CharSetUtils.count(*, null)        = 0
         CharSetUtils.count(*, "")          = 0
         CharSetUtils.count("hello", "k-p") = 3
         CharSetUtils.count("hello", "a-e") = 1
         
        Parameters:
        str - String to count characters in, may be null
        set - String set of characters to count, may be null
        Returns:
        character count, zero if null string input
        See Also:
        for set-syntax.
      • count

        public static int count​(String str,
                                String[] set)

        Takes an argument in set-syntax, see evaluateSet, and returns the number of characters present in the specified string.

        An example would be:

        • count("hello", {"c-f", "o"}) returns 2.
        Parameters:
        str - String to count characters in, may be null
        set - String[] set of characters to count, may be null
        Returns:
        character count, zero if null string input
        See Also:
        for set-syntax.
      • keep

        public static String keep​(String str,
                                  String set)

        Takes an argument in set-syntax, see evaluateSet, and keeps any of characters present in the specified string.

         CharSetUtils.keep(null, *)        = null
         CharSetUtils.keep("", *)          = ""
         CharSetUtils.keep(*, null)        = ""
         CharSetUtils.keep(*, "")          = ""
         CharSetUtils.keep("hello", "hl")  = "hll"
         CharSetUtils.keep("hello", "le")  = "ell"
         
        Parameters:
        str - String to keep characters from, may be null
        set - String set of characters to keep, may be null
        Returns:
        modified String, null if null string input
        Since:
        2.0
        See Also:
        for set-syntax.
      • keep

        public static String keep​(String str,
                                  String[] set)

        Takes an argument in set-syntax, see evaluateSet, and keeps any of characters present in the specified string.

        An example would be:

        • keep("hello", {"c-f", "o"}) returns "eo"
        Parameters:
        str - String to keep characters from, may be null
        set - String[] set of characters to keep, may be null
        Returns:
        modified String, null if null string input
        Since:
        2.0
        See Also:
        for set-syntax.
      • delete

        public static String delete​(String str,
                                    String set)

        Takes an argument in set-syntax, see evaluateSet, and deletes any of characters present in the specified string.

         CharSetUtils.delete(null, *)        = null
         CharSetUtils.delete("", *)          = ""
         CharSetUtils.delete(*, null)        = *
         CharSetUtils.delete(*, "")          = *
         CharSetUtils.delete("hello", "hl")  = "eo"
         CharSetUtils.delete("hello", "le")  = "ho"
         
        Parameters:
        str - String to delete characters from, may be null
        set - String set of characters to delete, may be null
        Returns:
        modified String, null if null string input
        See Also:
        for set-syntax.
      • delete

        public static String delete​(String str,
                                    String[] set)

        Takes an argument in set-syntax, see evaluateSet, and deletes any of characters present in the specified string.

        An example would be:

        • delete("hello", {"c-f", "o"}) returns "hll"
        Parameters:
        str - String to delete characters from, may be null
        set - String[] set of characters to delete, may be null
        Returns:
        modified String, null if null string input
        See Also:
        for set-syntax.
      • translate

        public static String translate​(String str,
                                       String searchChars,
                                       String replaceChars)
        Deprecated.
        Use StringUtils.replaceChars(String, String, String). Method will be removed in Commons Lang 3.0. NOTE: StringUtils#replaceChars behaves differently when 'searchChars' is longer than 'replaceChars'. CharSetUtils#translate will use the last char of the replacement string whereas StringUtils#replaceChars will delete

        Translate characters in a String. This is a multi character search and replace routine.

        An example is:

        • translate("hello", "ho", "jy") => jelly

        If the length of characters to search for is greater than the length of characters to replace, then the last character is used.

         CharSetUtils.translate(null, *, *) = null
         CharSetUtils.translate("", *, *)   = ""
         
        Parameters:
        str - String to replace characters in, may be null
        searchChars - a set of characters to search for, must not be null
        replaceChars - a set of characters to replace, must not be null or empty ("")
        Returns:
        translated String, null if null string input
        Throws:
        NullPointerException - if searchChars or replaceChars is null
        ArrayIndexOutOfBoundsException - if replaceChars is empty ("")