Class StringUtils


  • @Immutable
    public final class StringUtils
    extends java.lang.Object
    Utilities for working with strings.

    This class is internal and is hence not for public use. Its APIs are unstable and can change at any time.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private StringUtils()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static boolean isNullOrEmpty​(java.lang.String string)
      Returns true if the given string is null or is the empty string.
      private static boolean isPrintableChar​(char ch)  
      static boolean isPrintableString​(java.lang.String str)
      Determines whether the String contains only printable characters.
      static java.lang.String padLeft​(java.lang.String value, int minLength)
      Pads a given string on the left with leading 0's up the length.
      private static java.lang.String padStart​(java.lang.String string, int minLength, char padChar)
      Returns a string, of length at least minLength, consisting of string prepended with as many copies of padChar as are necessary to reach that length.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • StringUtils

        private StringUtils()
    • Method Detail

      • isNullOrEmpty

        @Contract("null -> true")
        public static boolean isNullOrEmpty​(@Nullable
                                            java.lang.String string)
        Returns true if the given string is null or is the empty string.

        This method was copied verbatim from Guava library method com.google.common.base.Strings#isNullOrEmpty(java.lang.String).

        Parameters:
        string - a string reference to check
        Returns:
        true if the string is null or is the empty string
      • padLeft

        public static java.lang.String padLeft​(java.lang.String value,
                                               int minLength)
        Pads a given string on the left with leading 0's up the length.
        Parameters:
        value - the string to pad
        minLength - the minimum length the resulting padded string must have. Can be zero or negative, in which case the input string is always returned.
        Returns:
        the padded string
      • padStart

        private static java.lang.String padStart​(java.lang.String string,
                                                 int minLength,
                                                 char padChar)
        Returns a string, of length at least minLength, consisting of string prepended with as many copies of padChar as are necessary to reach that length. For example,
        • padStart("7", 3, '0') returns "007"
        • padStart("2010", 3, '0') returns "2010"

        See Formatter for a richer set of formatting capabilities.

        This method was copied almost verbatim from Guava library method com.google.common.base.Strings#padStart(java.lang.String, int, char).

        Parameters:
        string - the string which should appear at the end of the result
        minLength - the minimum length the resulting string must have. Can be zero or negative, in which case the input string is always returned.
        padChar - the character to insert at the beginning of the result until the minimum length is reached
        Returns:
        the padded string
      • isPrintableString

        public static boolean isPrintableString​(java.lang.String str)
        Determines whether the String contains only printable characters.
        Parameters:
        str - the String to be validated.
        Returns:
        whether the String contains only printable characters.
      • isPrintableChar

        private static boolean isPrintableChar​(char ch)