Class ExistsRule

java.lang.Object

org.apache.log4j.rule.AbstractRule

org.apache.log4j.rule.ExistsRule

All Implemented Interfaces:

Serializable, Rule

public class ExistsRule
extends AbstractRule

A Rule class implementing a not null (and not empty string) check.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private final String	field	field name.
private static final LoggingEventFieldResolver	RESOLVER	field resolver.
(package private) static final long	serialVersionUID	Serialization id.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ExistsRule(String fld)	Create new instance.

Method Summary

Modifier and Type	Method	Description
boolean	evaluate(org.apache.log4j.spi.LoggingEvent event, Map matches)	Returns true if this implementation of the rule accepts the LoggingEvent, or false if not.
static Rule	getRule(String field)	Get an instance of ExistsRule.
static Rule	getRule(Stack stack)	Create an instance of ExistsRule using the top name on the stack.

Methods inherited from class AbstractRule

addPropertyChangeListener, firePropertyChange, firePropertyChange, removePropertyChangeListener

Methods inherited from class Object

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

Field Details

serialVersionUID

static final long serialVersionUID

Serialization id.

See Also:

• Constant Field Values

RESOLVER

private static final LoggingEventFieldResolver RESOLVER

field resolver.

field

private final String field

field name.

Constructor Details

ExistsRule

private ExistsRule(String fld)

Create new instance.

Parameters:

fld - field name.

Method Details

getRule

public static Rule getRule(String field)

Get an instance of ExistsRule.

Parameters:

field - field.

Returns:

instance of ExistsRule.

getRule

public static Rule getRule(Stack stack)

Create an instance of ExistsRule using the top name on the stack.

Parameters:

stack - stack

Returns:

instance of ExistsRule.

evaluate

public boolean evaluate(org.apache.log4j.spi.LoggingEvent event,
 Map matches)

Returns true if this implementation of the rule accepts the LoggingEvent, or false if not.

What True/False means can be client-specific.

Parameters:

event - LoggingEvent this instance will evaluate

matches - a Map of event field keys to Sets of matching strings (may be null) which will be updated during execution of this method to include field and string matches based on the rule evaluation results

Returns:

true if this Rule instance accepts the event, otherwise false.