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 * Adds a Marker as a parent to this Marker.
32 * @param markers The parent markers to add.
33 * @return The current Marker object, thus allowing multiple adds to be concatenated.
34 * @throws IllegalArgumentException if the argument is {@code null}
35 */
36 Marker addParents(Marker... markers);
37
38 /**
39 * Returns true if the given marker has the same name as this marker.
40 *
41 * @param obj the reference object with which to compare.
42 * @return true if the given marker has the same name as this marker.
43 * @since 2.4
44 */
45 @Override
46 public boolean equals(Object obj);
47
48 /**
49 * Returns the name of this Marker.
50 * @return The name of the Marker.
51 */
52 String getName();
53
54 /**
55 * Returns a list of parents of this Marker.
56 * @return The parent Markers or {@code null} if this Marker has no parents.
57 */
58 Marker[] getParents();
59
60 /**
61 * Returns a hash code value based on the name of this marker.
62 * Markers are equal if they have the same name.
63 * @return the computed hash code
64 * @since 2.4
65 */
66 @Override
67 public int hashCode();
68
69 /**
70 * Indicates whether this Marker has references to any other Markers.
71 * @return {@code true} if the Marker has parent Markers
72 */
73 boolean hasParents();
74
75 /**
76 * Checks whether this Marker is an instance of the specified Marker.
77 * @param m The Marker to check.
78 * @return {@code true} if this Marker or one of its ancestors is the specified Marker, {@code false} otherwise.
79 * @throws IllegalArgumentException if the argument is {@code null}
80 */
81 boolean isInstanceOf(Marker m);
82
83 /**
84 * Checks whether this Marker is an instance of the specified Marker.
85 * @param name The name of the Marker.
86 * @return {@code true} if this Marker or one of its ancestors matches the specified name, {@code false} otherwise.
87 * @throws IllegalArgumentException if the argument is {@code null}
88 */
89 boolean isInstanceOf(String name);
90
91 /**
92 * Removes the specified Marker as a parent of this Marker.
93 * @param marker The marker to remove.
94 * @return {@code true} if the marker was removed.
95 * @throws IllegalArgumentException if the argument is {@code null}
96 */
97 boolean remove(Marker marker);
98
99 /**
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 }