1/**
2 * Copyright (c) 2004-2011 QOS.ch
3 * All rights reserved.
4 *
5 * Permission is hereby granted, free  of charge, to any person obtaining
6 * a  copy  of this  software  and  associated  documentation files  (the
7 * "Software"), to  deal in  the Software without  restriction, including
8 * without limitation  the rights to  use, copy, modify,  merge, publish,
9 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
10 * permit persons to whom the Software  is furnished to do so, subject to
11 * the following conditions:
12 *
13 * The  above  copyright  notice  and  this permission  notice  shall  be
14 * included in all copies or substantial portions of the Software.
15 *
16 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
17 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
18 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
19 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
22 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23 *
24 */
25package org.slf4j;
26
27import java.io.Serializable;
28import java.util.Iterator;
29
30/**
31 * Markers are named objects used to enrich log statements. Conforming logging
32 * system Implementations of SLF4J determine how information conveyed by markers
33 * are used, if at all. In particular, many conforming logging systems ignore
34 * marker data.
35 *
36 * <p>
37 * Markers can contain references to other markers, which in turn may contain
38 * references of their own.
39 *
40 * @author Ceki G&uuml;lc&uuml;
41 */
42public interface Marker extends Serializable {
43
44    /**
45     * This constant represents any marker, including a null marker.
46     */
47    public final String ANY_MARKER = "*";
48
49    /**
50     * This constant represents any non-null marker.
51     */
52    public final String ANY_NON_NULL_MARKER = "+";
53
54    /**
55     * Get the name of this Marker.
56     *
57     * @return name of marker
58     */
59    public String getName();
60
61    /**
62     * Add a reference to another Marker.
63     *
64     * @param reference
65     *                a reference to another marker
66     * @throws IllegalArgumentException
67     *                 if 'reference' is null
68     */
69    public void add(Marker reference);
70
71    /**
72     * Remove a marker reference.
73     *
74     * @param reference
75     *                the marker reference to remove
76     * @return true if reference could be found and removed, false otherwise.
77     */
78    public boolean remove(Marker reference);
79
80    /**
81     * @deprecated Replaced by {@link #hasReferences()}.
82     */
83    public boolean hasChildren();
84
85    /**
86     * Does this marker have any references?
87     *
88     * @return true if this marker has one or more references, false otherwise.
89     */
90    public boolean hasReferences();
91
92    /**
93     * Returns an Iterator which can be used to iterate over the references of this
94     * marker. An empty iterator is returned when this marker has no references.
95     *
96     * @return Iterator over the references of this marker
97     */
98    public Iterator<Marker> iterator();
99
100    /**
101     * Does this marker contain a reference to the 'other' marker? Marker A is defined
102     * to contain marker B, if A == B or if B is referenced by A, or if B is referenced
103     * by any one of A's references (recursively).
104     *
105     * @param other
106     *                The marker to test for inclusion.
107     * @throws IllegalArgumentException
108     *                 if 'other' is null
109     * @return Whether this marker contains the other marker.
110     */
111    public boolean contains(Marker other);
112
113    /**
114     * Does this marker contain the marker named 'name'?
115     *
116     * If 'name' is null the returned value is always false.
117     *
118     * @param name The marker name to test for inclusion.
119     * @return Whether this marker contains the other marker.
120     */
121    public boolean contains(String name);
122
123    /**
124     * Markers are considered equal if they have the same name.
125     *
126     * @param o
127     * @return true, if this.name equals o.name
128     *
129     * @since 1.5.1
130     */
131    public boolean equals(Object o);
132
133    /**
134     * Compute the hash code based on the name of this marker.
135     * Note that markers are considered equal if they have the same name.
136     *
137     * @return the computed hashCode
138     * @since 1.5.1
139     */
140    public int hashCode();
141
142}
143