Package io.netty.util.internal.logging

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.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static FormattingTuple arrayFormat​(java.lang.String messagePattern, java.lang.Object[] argArray)
      Same principle as the format(String, Object) and format(String, Object, Object) methods except that any number of arguments can be passed in an array.
      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 argA, java.lang.Object argB)
      Performs a two argument substitution for the 'messagePattern' passed as parameter.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Method Detail

      • format

        public static 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 FormattingTuple format​(java.lang.String messagePattern,
                                     java.lang.Object argA,
                                     java.lang.Object argB)
        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
        argA - The argument to be substituted in place of the first formatting anchor
        argB - The argument to be substituted in place of the second formatting anchor
        Returns:
        The formatted message

      • arrayFormat

        public static FormattingTuple arrayFormat​(java.lang.String messagePattern,
                                          java.lang.Object[] argArray)
        Same principle as the format(String, Object) and format(String, Object, Object) methods except that any number of arguments can be passed in an array.
        Parameters:
        messagePattern - The message pattern which will be parsed and formatted
        argArray - An array of arguments to be substituted in place of formatting anchors
        Returns:
        The formatted message