Class MessageFormatter


  • public final class MessageFormatter
    extends java.lang.Object
    Formats messages according to very simple substitution rules. Substitutions can be made 1, 2 or more arguments.

    For example,

     MessageFormatter.format("Hi {}.", "there")
     
    will return the string "Hi there.".

    The {} pair is called the formatting anchor. It serves to designate the location where arguments need to be substituted within the message pattern.

    In case your message contains the '{' or the '}' character, you do not have to do anything special unless the '}' character immediately follows '{'. For example,

     MessageFormatter.format("Set {1,2,3} is not equal to {}.", "1,2");
     
    will return the string "Set {1,2,3} is not equal to 1,2.".

    If for whatever reason you need to place the string "{}" in the message without its formatting anchor meaning, then you need to escape the '{' character with '\', that is the backslash character. Only the '{' character should be escaped. There is no need to escape the '}' character. For example,

     MessageFormatter.format("Set \\{} is not equal to {}.", "1,2");
     
    will return the string "Set {} is not equal to 1,2.".

    The escaping behavior just described can be overridden by escaping the escape character '\'. Calling

     MessageFormatter.format("File name is C:\\\\{}.", "file.zip");
     
    will return the string "File name is C:\file.zip".

    The formatting conventions are different than those of MessageFormat which ships with the Java platform. This is justified by the fact that SLF4J's implementation is 10 times faster than that of MessageFormat. This local performance difference is both measurable and significant in the larger context of the complete logging processing chain.

    See also format(String, Object), format(String, Object, Object) and arrayFormat(String, Object[]) methods for more details.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      (package private) static char DELIM_START  
      (package private) static char DELIM_STOP  
      (package private) static java.lang.String DELIM_STR  
      private static char ESCAPE_CHAR  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static FormattingTuple arrayFormat​(java.lang.String messagePattern, java.lang.Object[] argArray)  
      static FormattingTuple arrayFormat​(java.lang.String messagePattern, java.lang.Object[] argArray, java.lang.Throwable throwable)  
      private static void booleanArrayAppend​(java.lang.StringBuilder sbuf, boolean[] a)  
      private static void byteArrayAppend​(java.lang.StringBuilder sbuf, byte[] a)  
      private static void charArrayAppend​(java.lang.StringBuilder sbuf, char[] a)  
      private static void deeplyAppendParameter​(java.lang.StringBuilder sbuf, java.lang.Object o, java.util.Map<java.lang.Object[],​java.lang.Object> seenMap)  
      private static void doubleArrayAppend​(java.lang.StringBuilder sbuf, double[] a)  
      private static void floatArrayAppend​(java.lang.StringBuilder sbuf, float[] a)  
      static FormattingTuple format​(java.lang.String messagePattern, java.lang.Object arg)
      Performs single argument substitution for the 'messagePattern' passed as parameter.
      static FormattingTuple format​(java.lang.String messagePattern, java.lang.Object arg1, java.lang.Object arg2)
      Performs a two argument substitution for the 'messagePattern' passed as parameter.
      (package private) static java.lang.Throwable getThrowableCandidate​(java.lang.Object[] argArray)  
      private static void intArrayAppend​(java.lang.StringBuilder sbuf, int[] a)  
      (package private) static boolean isDoubleEscaped​(java.lang.String messagePattern, int delimeterStartIndex)  
      (package private) static boolean isEscapedDelimeter​(java.lang.String messagePattern, int delimeterStartIndex)  
      private static void longArrayAppend​(java.lang.StringBuilder sbuf, long[] a)  
      private static void objectArrayAppend​(java.lang.StringBuilder sbuf, java.lang.Object[] a, java.util.Map<java.lang.Object[],​java.lang.Object> seenMap)  
      private static void safeObjectAppend​(java.lang.StringBuilder sbuf, java.lang.Object o)  
      private static void shortArrayAppend​(java.lang.StringBuilder sbuf, short[] a)  
      private static java.lang.Object[] trimmedCopy​(java.lang.Object[] argArray)  
      • Methods inherited from class java.lang.Object

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

      • MessageFormatter

        public MessageFormatter()
    • Method Detail

      • format

        public static final FormattingTuple format​(java.lang.String messagePattern,
                                                   java.lang.Object arg)
        Performs single argument substitution for the 'messagePattern' passed as parameter.

        For example,

         MessageFormatter.format("Hi {}.", "there");
         
        will return the string "Hi there.".

        Parameters:
        messagePattern - The message pattern which will be parsed and formatted
        arg - The argument to be substituted in place of the formatting anchor
        Returns:
        The formatted message
      • format

        public static final FormattingTuple format​(java.lang.String messagePattern,
                                                   java.lang.Object arg1,
                                                   java.lang.Object arg2)
        Performs a two argument substitution for the 'messagePattern' passed as parameter.

        For example,

         MessageFormatter.format("Hi {}. My name is {}.", "Alice", "Bob");
         
        will return the string "Hi Alice. My name is Bob.".
        Parameters:
        messagePattern - The message pattern which will be parsed and formatted
        arg1 - The argument to be substituted in place of the first formatting anchor
        arg2 - The argument to be substituted in place of the second formatting anchor
        Returns:
        The formatted message
      • getThrowableCandidate

        static final java.lang.Throwable getThrowableCandidate​(java.lang.Object[] argArray)
      • arrayFormat

        public static final FormattingTuple arrayFormat​(java.lang.String messagePattern,
                                                        java.lang.Object[] argArray)
      • trimmedCopy

        private static java.lang.Object[] trimmedCopy​(java.lang.Object[] argArray)
      • arrayFormat

        public static final FormattingTuple arrayFormat​(java.lang.String messagePattern,
                                                        java.lang.Object[] argArray,
                                                        java.lang.Throwable throwable)
      • isEscapedDelimeter

        static final boolean isEscapedDelimeter​(java.lang.String messagePattern,
                                                int delimeterStartIndex)
      • isDoubleEscaped

        static final boolean isDoubleEscaped​(java.lang.String messagePattern,
                                             int delimeterStartIndex)
      • deeplyAppendParameter

        private static void deeplyAppendParameter​(java.lang.StringBuilder sbuf,
                                                  java.lang.Object o,
                                                  java.util.Map<java.lang.Object[],​java.lang.Object> seenMap)
      • safeObjectAppend

        private static void safeObjectAppend​(java.lang.StringBuilder sbuf,
                                             java.lang.Object o)
      • objectArrayAppend

        private static void objectArrayAppend​(java.lang.StringBuilder sbuf,
                                              java.lang.Object[] a,
                                              java.util.Map<java.lang.Object[],​java.lang.Object> seenMap)
      • booleanArrayAppend

        private static void booleanArrayAppend​(java.lang.StringBuilder sbuf,
                                               boolean[] a)
      • byteArrayAppend

        private static void byteArrayAppend​(java.lang.StringBuilder sbuf,
                                            byte[] a)
      • charArrayAppend

        private static void charArrayAppend​(java.lang.StringBuilder sbuf,
                                            char[] a)
      • shortArrayAppend

        private static void shortArrayAppend​(java.lang.StringBuilder sbuf,
                                             short[] a)
      • intArrayAppend

        private static void intArrayAppend​(java.lang.StringBuilder sbuf,
                                           int[] a)
      • longArrayAppend

        private static void longArrayAppend​(java.lang.StringBuilder sbuf,
                                            long[] a)
      • floatArrayAppend

        private static void floatArrayAppend​(java.lang.StringBuilder sbuf,
                                             float[] a)
      • doubleArrayAppend

        private static void doubleArrayAppend​(java.lang.StringBuilder sbuf,
                                              double[] a)