1 /**
2 * Logback: the reliable, generic, fast and flexible logging framework.
3 * Copyright (C) 1999-2011, QOS.ch. All rights reserved.
4 *
5 * This program and the accompanying materials are dual-licensed under
6 * either the terms of the Eclipse Public License v1.0 as published by
7 * the Eclipse Foundation
8 *
9 * or (per the licensee's choosing)
10 *
11 * under the terms of the GNU Lesser General Public License version 2.1
12 * as published by the Free Software Foundation.
13 */
14 package ch.qos.logback.classic.sift;
15
16 import ch.qos.logback.classic.spi.ILoggingEvent;
17 import ch.qos.logback.core.sift.Discriminator;
18 import ch.qos.logback.core.spi.ContextAwareBase;
19 import ch.qos.logback.core.util.OptionHelper;
20
21 import java.util.Map;
22
23 /**
24 * MDCBasedDiscriminator essentially returns the value mapped to an MDC key. If
25 * the said value is null, then a default value is returned.
26 * <p/>
27 * <p>Both Key and the DefaultValue are user specified properties.
28 *
29 * @author Ceki Gülcü
30 */
31 public class MDCBasedDiscriminator extends ContextAwareBase implements
32 Discriminator<ILoggingEvent> {
33
34 private String key;
35 private String defaultValue;
36 private boolean started = false;
37
38 public MDCBasedDiscriminator() {
39 }
40
41 /**
42 * Return the value associated with an MDC entry designated by the Key
43 * property. If that value is null, then return the value assigned to the
44 * DefaultValue property.
45 */
46 public String getDiscriminatingValue(ILoggingEvent event) {
47 // http://jira.qos.ch/browse/LBCLASSIC-213
48 Map<String, String> mdcMap = event.getMDCPropertyMap();
49 if (mdcMap == null) {
50 return defaultValue;
51 }
52 String mdcValue = mdcMap.get(key);
53 if (mdcValue == null) {
54 return defaultValue;
55 } else {
56 return mdcValue;
57 }
58 }
59
60 public boolean isStarted() {
61 return started;
62 }
63
64 public void start() {
65 int errors = 0;
66 if (OptionHelper.isEmpty(key)) {
67 errors++;
68 addError("The \"Key\" property must be set");
69 }
70 if (OptionHelper.isEmpty(defaultValue)) {
71 errors++;
72 addError("The \"DefaultValue\" property must be set");
73 }
74 if (errors == 0) {
75 started = true;
76 }
77 }
78
79 public void stop() {
80 started = false;
81 }
82
83 public String getKey() {
84 return key;
85 }
86
87 public void setKey(String key) {
88 this.key = key;
89 }
90
91 /**
92 * @return
93 * @see #setDefaultValue(String)
94 */
95 public String getDefaultValue() {
96 return defaultValue;
97 }
98
99 /**
100 * The default MDC value in case the MDC is not set for
101 * {@link #setKey(String) mdcKey}.
102 * <p/>
103 * <p> For example, if {@link #setKey(String) Key} is set to the value
104 * "someKey", and the MDC is not set for "someKey", then this appender will
105 * use the default value, which you can set with the help of this method.
106 *
107 * @param defaultValue
108 */
109 public void setDefaultValue(String defaultValue) {
110 this.defaultValue = defaultValue;
111 }
112 }