1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache license, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the license for the specific language governing permissions and
15 * limitations under the license.
16 */
17 package org.apache.logging.log4j;
18
19 import java.io.Serializable;
20
21 /**
22 * Markers are objects that are used to add easily filterable information to log messages.
23 *
24 * Markers can be hierarchical - each Marker may have a parent. This allows for broad categories being subdivided into
25 * more specific categories. An example might be a Marker named "Error" with children named "SystemError" and
26 * "ApplicationError".
27 */
28 public interface Marker extends Serializable {
29
30 /**
31 * Adds a Marker as a parent to this Marker.
32 *
33 * @param markers The parent markers to add.
34 * @return The current Marker object, thus allowing multiple adds to be concatenated.
35 * @throws IllegalArgumentException if the argument is {@code null}
36 */
37 Marker addParents(Marker... markers);
38
39 /**
40 * Returns true if the given marker has the same name as this marker.
41 *
42 * @param obj the reference object with which to compare.
43 * @return true if the given marker has the same name as this marker.
44 * @since 2.4
45 */
46 @Override
47 boolean equals(Object obj);
48
49 /**
50 * Returns the name of this Marker.
51 *
52 * @return The name of the Marker.
53 */
54 String getName();
55
56 /**
57 * Returns a list of parents of this Marker.
58 *
59 * @return The parent Markers or {@code null} if this Marker has no parents.
60 */
61 Marker[] getParents();
62
63 /**
64 * Returns a hash code value based on the name of this marker. Markers are equal if they have the same name.
65 *
66 * @return the computed hash code
67 * @since 2.4
68 */
69 @Override
70 int hashCode();
71
72 /**
73 * Indicates whether this Marker has references to any other Markers.
74 *
75 * @return {@code true} if the Marker has parent Markers
76 */
77 boolean hasParents();
78
79 /**
80 * Checks whether this Marker is an instance of the specified Marker.
81 *
82 * @param m The Marker to check.
83 * @return {@code true} if this Marker or one of its ancestors is the specified Marker, {@code false} otherwise.
84 * @throws IllegalArgumentException if the argument is {@code null}
85 */
86 boolean isInstanceOf(Marker m);
87
88 /**
89 * Checks whether this Marker is an instance of the specified Marker.
90 *
91 * @param name The name of the Marker.
92 * @return {@code true} if this Marker or one of its ancestors matches the specified name, {@code false} otherwise.
93 * @throws IllegalArgumentException if the argument is {@code null}
94 */
95 boolean isInstanceOf(String name);
96
97 /**
98 * Removes the specified Marker as a parent of this Marker.
99 *
100 * @param marker The marker to remove.
101 * @return {@code true} if the marker was removed.
102 * @throws IllegalArgumentException if the argument is {@code null}
103 */
104 boolean remove(Marker marker);
105
106 /**
107 * Replaces the set of parent Markers with the provided Markers.
108 *
109 * @param markers The new set of parent Markers or {@code null} to clear the parents.
110 * @return The current Marker object.
111 */
112 Marker setParents(Marker... markers);
113 }