Package org.apache.logging.log4j.core.config

Enum PropertiesPlugin.NullLookup

java.lang.Object

java.lang.Enum<PropertiesPlugin.NullLookup>

org.apache.logging.log4j.core.config.PropertiesPlugin.NullLookup

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<PropertiesPlugin.NullLookup>, StrLookup

Enclosing class:

PropertiesPlugin

private static enum PropertiesPlugin.NullLookup
extends java.lang.Enum<PropertiesPlugin.NullLookup>
implements StrLookup

Enum Constant Summary

Enum Constants

Enum Constant	Description
INSTANCE

Field Summary

Fields inherited from interface org.apache.logging.log4j.core.lookup.StrLookup

CATEGORY

Constructor Summary

Constructors

Modifier	Constructor	Description
private	NullLookup()

Method Summary

Modifier and Type	Method	Description
LookupResult	evaluate(java.lang.String key)	Same as StrLookup.lookup(String), but provides additional metadata describing the result.
LookupResult	evaluate(LogEvent event, java.lang.String key)	Same as StrLookup.lookup(LogEvent, String), but provides additional metadata describing the result.
java.lang.String	lookup(java.lang.String key)	Looks up a String key to a String value.
java.lang.String	lookup(LogEvent event, java.lang.String key)	Looks up a String key to a String value possibly using the current LogEvent.
static PropertiesPlugin.NullLookup	valueOf(java.lang.String name)	Returns the enum constant of this type with the specified name.
static PropertiesPlugin.NullLookup[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

INSTANCE

public static final PropertiesPlugin.NullLookup INSTANCE

Constructor Detail

NullLookup

private NullLookup()

Method Detail

values

public static PropertiesPlugin.NullLookup[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (PropertiesPlugin.NullLookup c : PropertiesPlugin.NullLookup.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static PropertiesPlugin.NullLookup valueOf(java.lang.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:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null

lookup

public java.lang.String lookup(java.lang.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 java.lang.String lookup(LogEvent event,
                               java.lang.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(java.lang.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,
                             java.lang.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