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.impl;
26 
27 import java.util.concurrent.ConcurrentHashMap;
28 import java.util.concurrent.ConcurrentMap;
29 
30 import org.apache.commons.logging.LogFactory;
31 import org.slf4j.ILoggerFactory;
32 import org.slf4j.Logger;
33 import org.slf4j.helpers.Util;
34 
35 /**
36  * JCLLoggerFactory is an implementation of {@link ILoggerFactory} returning the
37  * appropriately named {@link JCLLoggerAdapter} instance.
38  *
39  * @author Ceki Gülcü
40  */
41 public class JCLLoggerFactory implements ILoggerFactory {
42 
43     private static final String JCL_DELEGATION_LOOP_URL = "http://www.slf4j.org/codes.html#jclDelegationLoop";
44 
45     // check for delegation loops
46     static {
47         try {
48             Class.forName("org.apache.commons.logging.impl.SLF4JLogFactory");
49             String part1 = "Detected both jcl-over-slf4j.jar AND slf4j-jcl.jar on the class path, preempting StackOverflowError. ";
50             String part2 = "See also " + JCL_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 JCLLoggerAdapter;
61     ConcurrentMap<String, Logger> loggerMap;
62 
JCLLoggerFactory()63     public JCLLoggerFactory() {
64         loggerMap = new ConcurrentHashMap<String, Logger>();
65     }
66 
67     /*
68      * (non-Javadoc)
69      *
70      * @see org.slf4j.ILoggerFactory#getLogger(java.lang.String)
71      */
getLogger(String name)72     public Logger getLogger(String name) {
73         Logger slf4jLogger = loggerMap.get(name);
74         if (slf4jLogger != null) {
75             return slf4jLogger;
76         } else {
77             org.apache.commons.logging.Log jclLogger = LogFactory.getLog(name);
78             Logger newInstance = new JCLLoggerAdapter(jclLogger, name);
79             Logger oldInstance = loggerMap.putIfAbsent(name, newInstance);
80             return oldInstance == null ? newInstance : oldInstance;
81         }
82     }
83 }
84