001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017
018 package org.apache.logging.log4j.core;
019
020 import org.apache.logging.log4j.Level;
021 import org.apache.logging.log4j.Marker;
022 import org.apache.logging.log4j.message.Message;
023 import org.apache.logging.log4j.util.EnglishEnums;
024
025 /**
026 * Interface that must be implemented to allow custom event filtering. It is highly recommended that
027 * applications make use of the Filters provided with this implementation before creating their own.
028 *
029 * <p>This interface supports "global" filters (i.e. - all events must pass through them first), attached to
030 * specific loggers and associated with Appenders. It is recommended that, where possible, Filter implementations
031 * create a generic filtering method that can be called from any of the filter methods.</p>
032 */
033 public interface Filter extends LifeCycle {
034
035 /**
036 * Main {@linkplain org.apache.logging.log4j.core.config.plugins.Plugin#elementType() plugin element type} for
037 * Filter plugins.
038 *
039 * @since 2.1
040 */
041 String ELEMENT_TYPE = "filter";
042
043 /**
044 * The result that can returned from a filter method call.
045 */
046 enum Result {
047 /**
048 * The event will be processed without further filtering based on the log Level.
049 */
050 ACCEPT,
051 /**
052 * No decision could be made, further filtering should occur.
053 */
054 NEUTRAL,
055 /**
056 * The event should not be processed.
057 */
058 DENY;
059
060 /**
061 * Returns the Result for the given string.
062 *
063 * @param name The Result enum name, case-insensitive. If null, returns, null
064 * @return a Result enum value or null if name is null
065 */
066 public static Result toResult(final String name) {
067 return toResult(name, null);
068 }
069
070 /**
071 * Returns the Result for the given string.
072 *
073 * @param name The Result enum name, case-insensitive. If null, returns, defaultResult
074 * @param defaultResult the Result to return if name is null
075 * @return a Result enum value or null if name is null
076 */
077 public static Result toResult(final String name, final Result defaultResult) {
078 return EnglishEnums.valueOf(Result.class, name, defaultResult);
079 }
080 }
081
082 /**
083 * Returns the result that should be returned when the filter does not match the event.
084 * @return the Result that should be returned when the filter does not match the event.
085 */
086 Result getOnMismatch();
087 /**
088 * Returns the result that should be returned when the filter matches the event.
089 * @return the Result that should be returned when the filter matches the event.
090 */
091 Result getOnMatch();
092
093 /**
094 * Filter an event.
095 * @param logger The Logger.
096 * @param level The event logging Level.
097 * @param marker The Marker for the event or null.
098 * @param msg String text to filter on.
099 * @param params An array of parameters or null.
100 * @return the Result.
101 */
102 Result filter(Logger logger, Level level, Marker marker, String msg, Object... params);
103
104 /**
105 * Filter an event.
106 * @param logger The Logger.
107 * @param level The event logging Level.
108 * @param marker The Marker for the event or null.
109 * @param msg Any Object.
110 * @param t A Throwable or null.
111 * @return the Result.
112 */
113 Result filter(Logger logger, Level level, Marker marker, Object msg, Throwable t);
114
115 /**
116 * Filter an event.
117 * @param logger The Logger.
118 * @param level The event logging Level.
119 * @param marker The Marker for the event or null.
120 * @param msg The Message
121 * @param t A Throwable or null.
122 * @return the Result.
123 */
124 Result filter(Logger logger, Level level, Marker marker, Message msg, Throwable t);
125
126 /**
127 * Filter an event.
128 * @param event The Event to filter on.
129 * @return the Result.
130 */
131 Result filter(LogEvent event);
132
133 }