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 */
25 package org.slf4j.log4j12;
26
27 import java.util.concurrent.ConcurrentHashMap;
28 import java.util.concurrent.ConcurrentMap;
29
30 import org.apache.log4j.LogManager;
31 import org.slf4j.ILoggerFactory;
32 import org.slf4j.Logger;
33 import org.slf4j.helpers.Util;
34
35 /**
36 * Log4jLoggerFactory is an implementation of {@link ILoggerFactory} returning
37 * the appropriate named {@link Log4jLoggerAdapter} instance.
38 *
39 * @author Ceki Gülcü
40 */
41 public class Log4jLoggerFactory implements ILoggerFactory {
42
43 private static final String LOG4J_DELEGATION_LOOP_URL = "http://www.slf4j.org/codes.html#log4jDelegationLoop";
44
45 // check for delegation loops
46 static {
47 try {
48 Class.forName("org.apache.log4j.Log4jLoggerFactory");
49 String part1 = "Detected both log4j-over-slf4j.jar AND bound slf4j-log4j12.jar on the class path, preempting StackOverflowError. ";
50 String part2 = "See also " + LOG4J_DELEGATION_LOOP_URL + " for more details.";
51
52 Util.report(part1);
53 Util.report(part2);
54 throw new IllegalStateException(part1 + part2);
55 } catch (ClassNotFoundException e) {
56 // this is the good case
57 }
58 }
59
60 // key: name (String), value: a Log4jLoggerAdapter;
61 ConcurrentMap<String, Logger> loggerMap;
62
63 public Log4jLoggerFactory() {
64 loggerMap = new ConcurrentHashMap<>();
65 // force log4j to initialize
66 org.apache.log4j.LogManager.getRootLogger();
67 }
68
69 /*
70 * (non-Javadoc)
71 *
72 * @see org.slf4j.ILoggerFactory#getLogger(java.lang.String)
73 */
74 public Logger getLogger(String name) {
75 Logger slf4jLogger = loggerMap.get(name);
76 if (slf4jLogger != null) {
77 return slf4jLogger;
78 } else {
79 org.apache.log4j.Logger log4jLogger;
80 if (name.equalsIgnoreCase(Logger.ROOT_LOGGER_NAME))
81 log4jLogger = LogManager.getRootLogger();
82 else
83 log4jLogger = LogManager.getLogger(name);
84
85 Logger newInstance = new Log4jLoggerAdapter(log4jLogger);
86 Logger oldInstance = loggerMap.putIfAbsent(name, newInstance);
87 return oldInstance == null ? newInstance : oldInstance;
88 }
89 }
90 }