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
25 * being subdivided into more specific categories. An example might be a Marker named "Error" with
26 * children named "SystemError" and "ApplicationError".
27 */
28 public interface Marker extends Serializable {
29
30 /**
31 * Returns the name of this Marker.
32 * @return The name of the Marker.
33 */
34 String getName();
35
36 /**
37 * Returns a list of parents of this Marker.
38 * @return The parent Markers or {@code null} if this Marker has no parents.
39 */
40 Marker[] getParents();
41
42 /**
43 * Indicates whether this Marker has references to any other Markers.
44 * @return {@code true} if the Marker has parent Markers
45 */
46 boolean hasParents();
47
48 /**
49 * Checks whether this Marker is an instance of the specified Marker.
50 * @param m The Marker to check.
51 * @return {@code true} if this Marker or one of its ancestors is the specified Marker, {@code false} otherwise.
52 * @throws IllegalArgumentException if the argument is {@code null}
53 */
54 boolean isInstanceOf(Marker m);
55
56 /**
57 * Checks whether this Marker is an instance of the specified Marker.
58 * @param name The name of the Marker.
59 * @return {@code true} if this Marker or one of its ancestors matches the specified name, {@code false} otherwise.
60 * @throws IllegalArgumentException if the argument is {@code null}
61 */
62 boolean isInstanceOf(String name);
63
64 /**
65 * Adds a Marker as a parent to this Marker.
66 * @param markers The parent markers to add.
67 * @return The current Marker object, thus allowing multiple adds to be concatenated.
68 * @throws IllegalArgumentException if the argument is {@code null}
69 */
70 Marker addParents(Marker... markers);
71
72 /**
73 * Replaces the set of parent Markers with the provided Markers.
74 * @param markers The new set of parent Markers or {@code null} to clear the parents.
75 * @return The current Marker object.
76 */
77 Marker setParents(Marker... markers);
78
79 /**
80 * Removes the specified Marker as a parent of this Marker.
81 * @param marker The marker to remove.
82 * @return {@code true} if the marker was removed.
83 * @throws IllegalArgumentException if the argument is {@code null}
84 */
85 boolean remove(Marker marker);
86 }