Marker.java revision 9f10490a05f7344f4b3ef657e8991f5d51934e2f 
1/*
2 * Copyright (c) 2004-2008 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 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 other
119   *                The marker to test for inclusion.
120   * @return Whether this marker contains the other marker.
121   */
122  public boolean contains(String name);
123
124  /**
125   * Markers are considered equal if they have the same name.
126   *
127   * @param o
128   * @return true, if this.name equals o.name
129   *
130   * @since 1.5.1
131   */
132  public boolean equals(Object o);
133
134  /**
135   * Compute the hash code based on the name of this marker.
136   * Note that markers are considered equal if they have the same name.
137   *
138   * @return the computed hashCode
139   * @since 1.5.1
140   */
141  public int hashCode();
142
143}
144