Enum PropertiesPlugin.NullLookup

java.lang.Object
java.lang.Enum<PropertiesPlugin.NullLookup>
org.apache.logging.log4j.core.config.PropertiesPlugin.NullLookup
All Implemented Interfaces:
Serializable, Comparable<PropertiesPlugin.NullLookup>, java.lang.constant.Constable, StrLookup
Enclosing class:
PropertiesPlugin

private static enum PropertiesPlugin.NullLookup extends Enum<PropertiesPlugin.NullLookup> implements StrLookup
  • Enum Constant Details

  • Constructor Details

    • NullLookup

      private NullLookup()
  • Method Details

    • values

      public static PropertiesPlugin.NullLookup[] values()
      Returns an array containing the constants of this enum type, in the order they are declared.
      Returns:
      an array containing the constants of this enum type, in the order they are declared
    • valueOf

      public static PropertiesPlugin.NullLookup valueOf(String name)
      Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum type has no constant with the specified name
      NullPointerException - if the argument is null
    • lookup

      public String lookup(String key)
      Description copied from interface: StrLookup
      Looks up a String key to a String value.

      The internal implementation may use any mechanism to return the value. The simplest implementation is to use a Map. However, virtually any implementation is possible.

      For example, it would be possible to implement a lookup that used the key as a primary key, and looked up the value on demand from the database Or, a numeric based implementation could be created that treats the key as an integer, increments the value and return the result as a string - converting 1 to 2, 15 to 16 etc.

      This method always returns a String, regardless of the underlying data, by converting it as necessary. For example:

       Map<String, Object> map = new HashMap<String, Object>();
       map.put("number", new Integer(2));
       assertEquals("2", StrLookup.mapLookup(map).lookup("number"));
       
      Specified by:
      lookup in interface StrLookup
      Parameters:
      key - the key to be looked up, may be null
      Returns:
      the matching value, null if no match
    • lookup

      public String lookup(LogEvent event, String key)
      Description copied from interface: StrLookup
      Looks up a String key to a String value possibly using the current LogEvent.

      The internal implementation may use any mechanism to return the value. The simplest implementation is to use a Map. However, virtually any implementation is possible.

      For example, it would be possible to implement a lookup that used the key as a primary key, and looked up the value on demand from the database Or, a numeric based implementation could be created that treats the key as an integer, increments the value and return the result as a string - converting 1 to 2, 15 to 16 etc.

      This method always returns a String, regardless of the underlying data, by converting it as necessary. For example:

       Map<String, Object> map = new HashMap<String, Object>();
       map.put("number", new Integer(2));
       assertEquals("2", StrLookup.mapLookup(map).lookup("number"));
       
      Specified by:
      lookup in interface StrLookup
      Parameters:
      event - The current LogEvent.
      key - the key to be looked up, may be null
      Returns:
      the matching value, null if no match
    • evaluate

      public LookupResult evaluate(String key)
      Description copied from interface: StrLookup
      Same as StrLookup.lookup(String), but provides additional metadata describing the result. Returns null if the key cannot be evaluated, otherwise a LookupResult wrapping the non-null string value.
      Specified by:
      evaluate in interface StrLookup
    • evaluate

      public LookupResult evaluate(LogEvent event, String key)
      Description copied from interface: StrLookup
      Same as StrLookup.lookup(LogEvent, String), but provides additional metadata describing the result. Returns null if the key cannot be evaluated, otherwise a LookupResult wrapping the non-null string value.
      Specified by:
      evaluate in interface StrLookup