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.spi;
18
19 import java.net.URL;
20 import java.util.Properties;
21
22 import org.apache.logging.log4j.Logger;
23 import org.apache.logging.log4j.status.StatusLogger;
24
25 /**
26 * Model class for a Log4j 2 provider. The properties in this class correspond to the properties used in a
27 * {@code META-INF/log4j-provider.properties} file. Note that this class is automatically created by Log4j and should
28 * not be used by providers.
29 */
30 public class Provider {
31 private static final Integer DEFAULT_PRIORITY = Integer.valueOf(-1);
32 /**
33 * Property name to set for a Log4j 2 provider to specify the priority of this implementation.
34 */
35 public static final String FACTORY_PRIORITY = "FactoryPriority";
36 /**
37 * Property name to set to the implementation of {@link org.apache.logging.log4j.spi.ThreadContextMap}.
38 */
39 public static final String THREAD_CONTEXT_MAP = "ThreadContextMap";
40 /**
41 * Property name to set to the implementation of {@link org.apache.logging.log4j.spi.LoggerContextFactory}.
42 */
43 public static final String LOGGER_CONTEXT_FACTORY = "LoggerContextFactory";
44
45 private static final Logger LOGGER = StatusLogger.getLogger();
46
47 private final Integer priority;
48 private final String className;
49 private final String threadContextMap;
50 private final URL url;
51 private final ClassLoader classLoader;
52
53 public Provider(final Properties props, final URL url, final ClassLoader classLoader) {
54 this.url = url;
55 this.classLoader = classLoader;
56 final String weight = props.getProperty(FACTORY_PRIORITY);
57 priority = weight == null ? DEFAULT_PRIORITY : Integer.valueOf(weight);
58 className = props.getProperty(LOGGER_CONTEXT_FACTORY);
59 threadContextMap = props.getProperty(THREAD_CONTEXT_MAP);
60 }
61
62 /**
63 * Gets the priority (natural ordering) of this Provider.
64 *
65 * @return the priority of this Provider
66 */
67 public Integer getPriority() {
68 return priority;
69 }
70
71 /**
72 * Gets the class name of the {@link org.apache.logging.log4j.spi.LoggerContextFactory} implementation of this
73 * Provider.
74 *
75 * @return the class name of a LoggerContextFactory implementation
76 */
77 public String getClassName() {
78 return className;
79 }
80
81 /**
82 * Loads the {@link org.apache.logging.log4j.spi.LoggerContextFactory} class specified by this Provider.
83 *
84 * @return the LoggerContextFactory implementation class or {@code null} if there was an error loading it
85 */
86 @SuppressWarnings("unchecked")
87 public Class<? extends LoggerContextFactory> loadLoggerContextFactory() {
88 if (className == null) {
89 return null;
90 }
91 try {
92 final Class<?> clazz = classLoader.loadClass(className);
93 if (LoggerContextFactory.class.isAssignableFrom(clazz)) {
94 return (Class<? extends LoggerContextFactory>) clazz;
95 }
96 } catch (final Exception e) {
97 LOGGER.error("Unable to create class {} specified in {}", className, url.toString(), e);
98 }
99 return null;
100 }
101
102 /**
103 * Gets the class name of the {@link org.apache.logging.log4j.spi.ThreadContextMap} implementation of this
104 * Provider.
105 *
106 * @return the class name of a ThreadContextMap implementation
107 */
108 public String getThreadContextMap() {
109 return threadContextMap;
110 }
111
112 /**
113 * Loads the {@link org.apache.logging.log4j.spi.ThreadContextMap} class specified by this Provider.
114 *
115 * @return the ThreadContextMap implementation class or {@code null} if there was an error loading it
116 */
117 @SuppressWarnings("unchecked")
118 public Class<? extends ThreadContextMap> loadThreadContextMap() {
119 if (threadContextMap == null) {
120 return null;
121 }
122 try {
123 final Class<?> clazz = classLoader.loadClass(threadContextMap);
124 if (ThreadContextMap.class.isAssignableFrom(clazz)) {
125 return (Class<? extends ThreadContextMap>) clazz;
126 }
127 } catch (final Exception e) {
128 LOGGER.error("Unable to create class {} specified in {}", threadContextMap, url.toString(), e);
129 }
130 return null;
131 }
132
133 /**
134 * Gets the URL containing this Provider's Log4j details.
135 *
136 * @return the URL corresponding to the Provider {@code META-INF/log4j-provider.properties} file
137 */
138 public URL getUrl() {
139 return url;
140 }
141 }