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