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1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   https://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.util.internal.logging;
17  
18  
19  import org.slf4j.Logger;
20  import org.slf4j.LoggerFactory;
21  import org.slf4j.helpers.NOPLoggerFactory;
22  import org.slf4j.spi.LocationAwareLogger;
23  
24  /**
25   * Logger factory which creates a <a href="https://www.slf4j.org/">SLF4J</a>
26   * logger.
27   */
28  public class Slf4JLoggerFactory extends InternalLoggerFactory {
29  
30      @SuppressWarnings("deprecation")
31      public static final InternalLoggerFactory INSTANCE = new Slf4JLoggerFactory();
32  
33      /**
34       * @deprecated Use {@link #INSTANCE} instead.
35       */
36      @Deprecated
37      public Slf4JLoggerFactory() {
38      }
39  
40      Slf4JLoggerFactory(boolean failIfNOP) {
41          assert failIfNOP; // Should be always called with true.
42          if (LoggerFactory.getILoggerFactory() instanceof NOPLoggerFactory) {
43              throw new NoClassDefFoundError("NOPLoggerFactory not supported");
44          }
45      }
46  
47      @Override
48      public InternalLogger newInstance(String name) {
49          return wrapLogger(LoggerFactory.getLogger(name));
50      }
51  
52      // package-private for testing.
53      static InternalLogger wrapLogger(Logger logger) {
54          return logger instanceof LocationAwareLogger ?
55                  new LocationAwareSlf4JLogger((LocationAwareLogger) logger) : new Slf4JLogger(logger);
56      }
57  
58      static InternalLoggerFactory getInstanceWithNopCheck() {
59          return NopInstanceHolder.INSTANCE_WITH_NOP_CHECK;
60      }
61  
62      private static final class NopInstanceHolder {
63          private static final InternalLoggerFactory INSTANCE_WITH_NOP_CHECK = new Slf4JLoggerFactory(true);
64      }
65  }