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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  
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
51            + " for more details.";
52  
53        Util.report(part1);
54        Util.report(part2);
55        throw new IllegalStateException(part1 + part2);
56      } catch (ClassNotFoundException e) {
57        // this is the good case
58      }
59    }
60  
61    // key: name (String), value: a JCLLoggerAdapter;
62    Map loggerMap;
63  
64    public JCLLoggerFactory() {
65      loggerMap = new HashMap();
66    }
67  
68    /*
69     * (non-Javadoc)
70     * 
71     * @see org.slf4j.ILoggerFactory#getLogger(java.lang.String)
72     */
73    public Logger getLogger(String name) {
74      Logger logger = null;
75      // protect against concurrent access of loggerMap
76      synchronized (this) {
77        logger = (Logger) loggerMap.get(name);
78        if (logger == null) {
79          org.apache.commons.logging.Log jclLogger = LogFactory.getLog(name);
80          logger = new JCLLoggerAdapter(jclLogger, name);
81          loggerMap.put(name, logger);
82        }
83      }
84      return logger;
85    }
86  }