Class Utils


  • public final class Utils
    extends java.lang.Object
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private Utils()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static void closeQuietly​(java.io.Closeable closeable)  
      static java.lang.String concat​(java.lang.CharSequence... strings)  
      static java.lang.String escape​(java.lang.String str, boolean escapeSingleQuote)  
      static java.lang.String hex​(char ch)
      Returns an upper case hexadecimal String for the given character.
      (package private) static int indexOf​(java.lang.CharSequence cs, java.lang.CharSequence searchChar, int start)
      Used by the indexOf(CharSequence methods) as a green implementation of indexOf.
      static boolean isEmpty​(java.lang.CharSequence cs)
      Checks if a CharSequence is empty ("") or null.
      static void isTrue​(boolean expression, java.lang.String message)
      Validate that the argument condition is true; otherwise throwing an exception with the specified message.
      static java.lang.String join​(java.lang.String delimiter, java.lang.Iterable<? extends java.lang.Object> objs)  
      static java.lang.String join​(java.lang.String delimiter, java.lang.String wrap, java.lang.Iterable<? extends java.lang.Object> objs)  
      static <T extends java.lang.CharSequence>
      T
      notEmpty​(T chars, java.lang.String message, java.lang.Object... values)
      Validate that the specified argument character sequence is neither null nor a length of zero (no characters); otherwise throwing an exception with the specified message.
      static <T> T notNull​(T object, java.lang.String message, java.lang.Object... values)
      Validate that the specified argument is not null; otherwise throwing an exception with the specified message.
      static void onlyOneIsTrue​(java.lang.String message, boolean... expressions)
      Check if one and only one condition is true; otherwise throw an exception with the specified message.
      static boolean onlyOneIsTrueNonThrow​(boolean... expressions)  
      static java.lang.String toString​(java.lang.Object o)  
      static java.lang.String unescape​(java.lang.String str)  
      • Methods inherited from class java.lang.Object

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

      • Utils

        private Utils()
    • Method Detail

      • join

        public static java.lang.String join​(java.lang.String delimiter,
                                            java.lang.String wrap,
                                            java.lang.Iterable<? extends java.lang.Object> objs)
      • join

        public static java.lang.String join​(java.lang.String delimiter,
                                            java.lang.Iterable<? extends java.lang.Object> objs)
      • concat

        public static java.lang.String concat​(java.lang.CharSequence... strings)
      • closeQuietly

        public static void closeQuietly​(java.io.Closeable closeable)
      • escape

        public static java.lang.String escape​(java.lang.String str,
                                              boolean escapeSingleQuote)
      • unescape

        public static java.lang.String unescape​(java.lang.String str)
      • hex

        public static java.lang.String hex​(char ch)
        Returns an upper case hexadecimal String for the given character.
        Parameters:
        ch - The character to map.
        Returns:
        An upper case hexadecimal String
      • isEmpty

        public static boolean isEmpty​(java.lang.CharSequence cs)

        Checks if a CharSequence is empty ("") or null.

         StringUtils.isEmpty(null)      = true
         StringUtils.isEmpty("")        = true
         StringUtils.isEmpty(" ")       = false
         StringUtils.isEmpty("bob")     = false
         StringUtils.isEmpty("  bob  ") = false
         

        NOTE: This method changed in Lang version 2.0. It no longer trims the CharSequence. That functionality is available in isBlank().

        Parameters:
        cs - the CharSequence to check, may be null
        Returns:
        true if the CharSequence is empty or null
        Since:
        3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence)
      • indexOf

        static int indexOf​(java.lang.CharSequence cs,
                           java.lang.CharSequence searchChar,
                           int start)
        Used by the indexOf(CharSequence methods) as a green implementation of indexOf.
        Parameters:
        cs - the CharSequence to be processed
        searchChar - the CharSequence to be searched for
        start - the start index
        Returns:
        the index where the search sequence was found
      • notNull

        public static <T> T notNull​(T object,
                                    java.lang.String message,
                                    java.lang.Object... values)

        Validate that the specified argument is not null; otherwise throwing an exception with the specified message.

        Validate.notNull(myObject, "The object must not be null");
        Type Parameters:
        T - the object type
        Parameters:
        object - the object to check
        message - the String.format(String, Object...) exception message if invalid, not null
        values - the optional values for the formatted exception message
        Returns:
        the validated object (never null for method chaining)
        Throws:
        java.lang.NullPointerException - if the object is null
      • isTrue

        public static void isTrue​(boolean expression,
                                  java.lang.String message)

        Validate that the argument condition is true; otherwise throwing an exception with the specified message. This method is useful when validating according to an arbitrary boolean expression, such as validating a primitive number or using your own custom validation expression.

        Validate.isTrue(i > 0.0, "The value must be greater than zero: %d", i);

        For performance reasons, the long value is passed as a separate parameter and appended to the exception message only in the case of an error.

        Parameters:
        expression - the boolean expression to check
        message -
        Throws:
        java.lang.IllegalArgumentException - if expression is false
      • onlyOneIsTrue

        public static void onlyOneIsTrue​(java.lang.String message,
                                         boolean... expressions)
        Check if one and only one condition is true; otherwise throw an exception with the specified message.
        Parameters:
        message - error describing message
        expressions - the boolean expressions to check
        Throws:
        java.lang.IllegalArgumentException - if zero or more than one expressions are true
      • onlyOneIsTrueNonThrow

        public static boolean onlyOneIsTrueNonThrow​(boolean... expressions)
      • notEmpty

        public static <T extends java.lang.CharSequence> T notEmpty​(T chars,
                                                                    java.lang.String message,
                                                                    java.lang.Object... values)

        Validate that the specified argument character sequence is neither null nor a length of zero (no characters); otherwise throwing an exception with the specified message.

        Validate.notEmpty(myString, "The string must not be empty");
        Type Parameters:
        T - the character sequence type
        Parameters:
        chars - the character sequence to check, validated not null by this method
        message - the String.format(String, Object...) exception message if invalid, not null
        values - the optional values for the formatted exception message, null array not recommended
        Returns:
        the validated character sequence (never null method for chaining)
        Throws:
        java.lang.NullPointerException - if the character sequence is null
        java.lang.IllegalArgumentException - if the character sequence is empty
      • toString

        public static java.lang.String toString​(java.lang.Object o)