1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.util.internal.logging;
17
18 /**
19 * Creates an {@link InternalLogger} or changes the default factory
20 * implementation. This factory allows you to choose what logging framework
21 * Netty should use. The default factory is {@link Slf4JLoggerFactory}. If SLF4J
22 * is not available, {@link Log4JLoggerFactory} is used. If Log4J is not available,
23 * {@link JdkLoggerFactory} is used. You can change it to your preferred
24 * logging framework before other Netty classes are loaded:
25 * <pre>
26 * {@link InternalLoggerFactory}.setDefaultFactory({@link Log4JLoggerFactory}.INSTANCE);
27 * </pre>
28 * Please note that the new default factory is effective only for the classes
29 * which were loaded after the default factory is changed. Therefore,
30 * {@link #setDefaultFactory(InternalLoggerFactory)} should be called as early
31 * as possible and shouldn't be called more than once.
32 */
33 public abstract class InternalLoggerFactory {
34 private static volatile InternalLoggerFactory defaultFactory;
35
36 @SuppressWarnings("UnusedCatchParameter")
37 private static InternalLoggerFactory newDefaultFactory(String name) {
38 InternalLoggerFactory f;
39 try {
40 f = new Slf4JLoggerFactory(true);
41 f.newInstance(name).debug("Using SLF4J as the default logging framework");
42 } catch (Throwable t1) {
43 try {
44 f = Log4JLoggerFactory.INSTANCE;
45 f.newInstance(name).debug("Using Log4J as the default logging framework");
46 } catch (Throwable t2) {
47 f = JdkLoggerFactory.INSTANCE;
48 f.newInstance(name).debug("Using java.util.logging as the default logging framework");
49 }
50 }
51 return f;
52 }
53
54 /**
55 * Returns the default factory. The initial default factory is
56 * {@link JdkLoggerFactory}.
57 */
58 public static InternalLoggerFactory getDefaultFactory() {
59 if (defaultFactory == null) {
60 defaultFactory = newDefaultFactory(InternalLoggerFactory.class.getName());
61 }
62 return defaultFactory;
63 }
64
65 /**
66 * Changes the default factory.
67 */
68 public static void setDefaultFactory(InternalLoggerFactory defaultFactory) {
69 if (defaultFactory == null) {
70 throw new NullPointerException("defaultFactory");
71 }
72 InternalLoggerFactory.defaultFactory = defaultFactory;
73 }
74
75 /**
76 * Creates a new logger instance with the name of the specified class.
77 */
78 public static InternalLogger getInstance(Class<?> clazz) {
79 return getInstance(clazz.getName());
80 }
81
82 /**
83 * Creates a new logger instance with the specified name.
84 */
85 public static InternalLogger getInstance(String name) {
86 return getDefaultFactory().newInstance(name);
87 }
88
89 /**
90 * Creates a new logger instance with the specified name.
91 */
92 protected abstract InternalLogger newInstance(String name);
93
94 }