Class Filter
- All Implemented Interfaces:
OptionHandler
- Direct Known Subclasses:
DenyAllFilter
,LevelMatchFilter
,LevelRangeFilter
,StringMatchFilter
Category
and
AppenderSkeleton
, the parent class of all standard
appenders, have built-in filtering rules. It is suggested that you first use
and understand the built-in rules before rushing to write your own custom
filters.
This abstract class assumes and also imposes that filters be organized in a
linear chain. The decide(LoggingEvent)
method of each filter
is called sequentially, in the order of their addition to the chain.
The decide(LoggingEvent)
method must return one of the
integer constants DENY
, NEUTRAL
or ACCEPT
.
If the value DENY
is returned, then the log event is dropped
immediately without consulting with the remaining filters.
If the value NEUTRAL
is returned, then the next filter in the chain
is consulted. If there are no more filters in the chain, then the log event
is logged. Thus, in the presence of no filters, the default behaviour is to
log all logging events.
If the value ACCEPT
is returned, then the log event is logged
without consulting the remaining filters.
The philosophy of log4j filters is largely inspired from the Linux ipchains.
Note that filtering is only supported by the
DOMConfigurator
. The
PropertyConfigurator
does not
support filters.
- Since:
- 0.9.0
- Author:
- Ceki Gülcü
-
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
The log event must be logged immediately without consulting with the remaining filters, if any, in the chain.static final int
The log event must be dropped immediately without consulting with the remaining filters, if any, in the chain.static final int
This filter is neutral with respect to the log event.Deprecated. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
Usually filters options become active when set.abstract int
decide
(LoggingEvent event) If the decision isDENY
, then the event will be dropped.getNext()
Return the pointer to the next filter;void
Set the next filter pointer.
-
Field Details
-
next
Deprecated.As of 1.2.12, usegetNext()
andsetNext(org.apache.log4j.spi.Filter)
insteadPoints to the next filter in the filter chain. -
DENY
public static final int DENYThe log event must be dropped immediately without consulting with the remaining filters, if any, in the chain.- See Also:
-
NEUTRAL
public static final int NEUTRALThis filter is neutral with respect to the log event. The remaining filters, if any, should be consulted for a final decision.- See Also:
-
ACCEPT
public static final int ACCEPTThe log event must be logged immediately without consulting with the remaining filters, if any, in the chain.- See Also:
-
-
Constructor Details
-
Filter
public Filter()
-
-
Method Details
-
activateOptions
public void activateOptions()Usually filters options become active when set. We provide a default do-nothing implementation for convenience.- Specified by:
activateOptions
in interfaceOptionHandler
-
decide
If the decision is
DENY
, then the event will be dropped. If the decision isNEUTRAL
, then the next filter, if any, will be invoked. If the decision is ACCEPT then the event will be logged without consulting with other filters in the chain.- Parameters:
event
- The LoggingEvent to decide upon.- Returns:
- decision The decision of the filter.
-
setNext
Set the next filter pointer. -
getNext
Return the pointer to the next filter;
-
getNext()
andsetNext(org.apache.log4j.spi.Filter)
instead