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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.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 G&uuml;lc&uuml;
    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 bound 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      final ConcurrentMap<String, Logger> loggerMap;
    62
    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       */
    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  }