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 */ 017package org.apache.logging.log4j; 018 019import java.io.Serializable; 020 021/** 022 * Markers are objects that are used to add easily filterable information to log messages. 023 * 024 * Markers can be hierarchical - each Marker may have a parent. This allows for broad categories 025 * being subdivided into more specific categories. An example might be a Marker named "Error" with 026 * children named "SystemError" and "ApplicationError". 027 */ 028public interface Marker extends Serializable { 029 030 /** 031 * Adds a Marker as a parent to this Marker. 032 * @param markers The parent markers to add. 033 * @return The current Marker object, thus allowing multiple adds to be concatenated. 034 * @throws IllegalArgumentException if the argument is {@code null} 035 */ 036 Marker addParents(Marker... markers); 037 038 /** 039 * Returns true if the given marker has the same name as this marker. 040 * 041 * @param obj the reference object with which to compare. 042 * @return true if the given marker has the same name as this marker. 043 * @since 2.4 044 */ 045 @Override 046 public boolean equals(Object obj); 047 048 /** 049 * Returns the name of this Marker. 050 * @return The name of the Marker. 051 */ 052 String getName(); 053 054 /** 055 * Returns a list of parents of this Marker. 056 * @return The parent Markers or {@code null} if this Marker has no parents. 057 */ 058 Marker[] getParents(); 059 060 /** 061 * Returns a hash code value based on the name of this marker. 062 * Markers are equal if they have the same name. 063 * @return the computed hash code 064 * @since 2.4 065 */ 066 @Override 067 public int hashCode(); 068 069 /** 070 * Indicates whether this Marker has references to any other Markers. 071 * @return {@code true} if the Marker has parent Markers 072 */ 073 boolean hasParents(); 074 075 /** 076 * Checks whether this Marker is an instance of the specified Marker. 077 * @param m The Marker to check. 078 * @return {@code true} if this Marker or one of its ancestors is the specified Marker, {@code false} otherwise. 079 * @throws IllegalArgumentException if the argument is {@code null} 080 */ 081 boolean isInstanceOf(Marker m); 082 083 /** 084 * Checks whether this Marker is an instance of the specified Marker. 085 * @param name The name of the Marker. 086 * @return {@code true} if this Marker or one of its ancestors matches the specified name, {@code false} otherwise. 087 * @throws IllegalArgumentException if the argument is {@code null} 088 */ 089 boolean isInstanceOf(String name); 090 091 /** 092 * Removes the specified Marker as a parent of this Marker. 093 * @param marker The marker to remove. 094 * @return {@code true} if the marker was removed. 095 * @throws IllegalArgumentException if the argument is {@code null} 096 */ 097 boolean remove(Marker marker); 098 099 /** 100 * Replaces the set of parent Markers with the provided Markers. 101 * @param markers The new set of parent Markers or {@code null} to clear the parents. 102 * @return The current Marker object. 103 */ 104 Marker setParents(Marker... markers); 105}