Package org.apache.logging.log4j.util

Class Unbox

  • public class Unbox
extends Object
    Utility for preventing primitive parameter values from being auto-boxed. Auto-boxing creates temporary objects which contribute to pressure on the garbage collector. With this utility users can convert primitive values directly into text without allocating temporary objects.

    Example usage: 

     import static org.apache.logging.log4j.util.Unbox.box;
 ...
 long longValue = 123456L;
 double doubleValue = 3.14;
 // prevent primitive values from being auto-boxed
 logger.debug("Long value={}, double value={}", box(longValue), box(doubleValue));

    This class manages a small thread-local ring buffer of StringBuilders. Each time one of the box() methods is called, the next slot in the ring buffer is used, until the ring buffer is full and the first slot is reused. By default the Unbox ring buffer has 32 slots, so user code can have up to 32 boxed primitives in a single logger call.

    If more slots are required, set system property log4j.unbox.ringbuffer.size to the desired ring buffer size. Note that the specified number will be rounded up to the nearest power of 2.

    Since:
    2.6

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static StringBuilder box​(boolean value)
      Returns a StringBuilder containing the text representation of the specified primitive value.
      static StringBuilder box​(byte value)
      Returns a StringBuilder containing the text representation of the specified primitive value.
      static StringBuilder box​(char value)
      Returns a StringBuilder containing the text representation of the specified primitive value.
      static StringBuilder box​(double value)
      Returns a StringBuilder containing the text representation of the specified primitive value.
      static StringBuilder box​(float value)
      Returns a StringBuilder containing the text representation of the specified primitive value.
      static StringBuilder box​(int value)
      Returns a StringBuilder containing the text representation of the specified primitive value.
      static StringBuilder box​(long value)
      Returns a StringBuilder containing the text representation of the specified primitive value.
      static StringBuilder box​(short value)
      Returns a StringBuilder containing the text representation of the specified primitive value.

    • Method Detail

      • box

        public static StringBuilder box​(float value)
        Returns a StringBuilder containing the text representation of the specified primitive value. This method will not allocate temporary objects.
        Parameters:
        value - the value whose text representation to return
        Returns:
        a StringBuilder containing the text representation of the specified primitive value

      • box

        public static StringBuilder box​(double value)
        Returns a StringBuilder containing the text representation of the specified primitive value. This method will not allocate temporary objects.
        Parameters:
        value - the value whose text representation to return
        Returns:
        a StringBuilder containing the text representation of the specified primitive value

      • box

        public static StringBuilder box​(short value)
        Returns a StringBuilder containing the text representation of the specified primitive value. This method will not allocate temporary objects.
        Parameters:
        value - the value whose text representation to return
        Returns:
        a StringBuilder containing the text representation of the specified primitive value

      • box

        public static StringBuilder box​(int value)
        Returns a StringBuilder containing the text representation of the specified primitive value. This method will not allocate temporary objects.
        Parameters:
        value - the value whose text representation to return
        Returns:
        a StringBuilder containing the text representation of the specified primitive value

      • box

        public static StringBuilder box​(char value)
        Returns a StringBuilder containing the text representation of the specified primitive value. This method will not allocate temporary objects.
        Parameters:
        value - the value whose text representation to return
        Returns:
        a StringBuilder containing the text representation of the specified primitive value

      • box

        public static StringBuilder box​(long value)
        Returns a StringBuilder containing the text representation of the specified primitive value. This method will not allocate temporary objects.
        Parameters:
        value - the value whose text representation to return
        Returns:
        a StringBuilder containing the text representation of the specified primitive value

      • box

        public static StringBuilder box​(byte value)
        Returns a StringBuilder containing the text representation of the specified primitive value. This method will not allocate temporary objects.
        Parameters:
        value - the value whose text representation to return
        Returns:
        a StringBuilder containing the text representation of the specified primitive value

      • box

        public static StringBuilder box​(boolean value)
        Returns a StringBuilder containing the text representation of the specified primitive value. This method will not allocate temporary objects.
        Parameters:
        value - the value whose text representation to return
        Returns:
        a StringBuilder containing the text representation of the specified primitive value