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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.HashMap;
28  import java.util.Map;
29  import java.util.concurrent.ConcurrentHashMap;
30  import java.util.concurrent.ConcurrentMap;
31  
32  import org.apache.commons.logging.LogFactory;
33  import org.slf4j.ILoggerFactory;
34  import org.slf4j.Logger;
35  import org.slf4j.helpers.Util;
36  
37  /**
38   * JCLLoggerFactory is an implementation of {@link ILoggerFactory} returning the
39   * appropriately named {@link JCLLoggerAdapter} instance.
40   * 
41   * @author Ceki Gülcü
42   */
43  public class JCLLoggerFactory implements ILoggerFactory {
44  
45    private static final String JCL_DELEGATION_LOOP_URL = "http://www.slf4j.org/codes.html#jclDelegationLoop";
46  
47    // check for delegation loops
48    static {
49      try {
50        Class.forName("org.apache.commons.logging.impl.SLF4JLogFactory");
51        String part1 = "Detected both jcl-over-slf4j.jar AND slf4j-jcl.jar on the class path, preempting StackOverflowError. ";
52        String part2 = "See also " + JCL_DELEGATION_LOOP_URL
53            + " for more details.";
54  
55        Util.report(part1);
56        Util.report(part2);
57        throw new IllegalStateException(part1 + part2);
58      } catch (ClassNotFoundException e) {
59        // this is the good case
60      }
61    }
62  
63    // key: name (String), value: a JCLLoggerAdapter;
64    ConcurrentMap<String, Logger> loggerMap;
65  
66    public JCLLoggerFactory() {
67      loggerMap = new ConcurrentHashMap<String, Logger>();
68    }
69  
70    /*
71     * (non-Javadoc)
72     * 
73     * @see org.slf4j.ILoggerFactory#getLogger(java.lang.String)
74     */
75    public Logger getLogger(String name) {
76      Logger slf4jLogger = loggerMap.get(name);
77      if (slf4jLogger != null) {
78        return slf4jLogger;
79      } else {
80        org.apache.commons.logging.Log jclLogger = LogFactory.getLog(name);
81        Logger newInstance = new JCLLoggerAdapter(jclLogger, name);
82        Logger oldInstance = loggerMap.putIfAbsent(name, newInstance);
83        return oldInstance == null ? newInstance : oldInstance;
84      }
85    }
86  }