View Javadoc

1   /*
2    * Copyright 2009 Red Hat, Inc.
3    *
4    * Red Hat licenses this file to you under the Apache License, version 2.0
5    * (the "License"); you may not use this file except in compliance with the
6    * License.  You may obtain a copy of the License at:
7    *
8    *    http://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 org.jboss.netty.logging;
17  
18  import org.osgi.framework.BundleContext;
19  import org.osgi.framework.ServiceReference;
20  import org.osgi.service.log.LogService;
21  import org.osgi.util.tracker.ServiceTracker;
22  
23  /**
24   * Logger factory which creates an <a href="http://www.osgi.org/">OSGi</a>
25   * {@link LogService} logger.
26   *
27   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
28   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
29   *
30   * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
31   *
32   */
33  public class OsgiLoggerFactory extends InternalLoggerFactory {
34  
35      private final ServiceTracker logServiceTracker;
36      private final InternalLoggerFactory fallback;
37      volatile LogService logService;
38  
39      public OsgiLoggerFactory(BundleContext ctx) {
40          this(ctx, null);
41      }
42  
43      public OsgiLoggerFactory(BundleContext ctx, InternalLoggerFactory fallback) {
44          if (ctx == null) {
45              throw new NullPointerException("ctx");
46          }
47          if (fallback == null) {
48              fallback = InternalLoggerFactory.getDefaultFactory();
49              if (fallback instanceof OsgiLoggerFactory) {
50                  fallback = new JdkLoggerFactory();
51              }
52          }
53  
54          this.fallback = fallback;
55          logServiceTracker = new ServiceTracker(
56                  ctx, "org.osgi.service.log.LogService", null) {
57                      @Override
58                      public Object addingService(ServiceReference reference) {
59                          LogService service = (LogService) super.addingService(reference);
60                          logService = service;
61                          return service;
62                      }
63  
64                      @Override
65                      public void removedService(ServiceReference reference,
66                              Object service) {
67                          logService = null;
68                      }
69          };
70          logServiceTracker.open();
71      }
72  
73      public InternalLoggerFactory getFallback() {
74          return fallback;
75      }
76  
77      public LogService getLogService() {
78          return logService;
79      }
80  
81      public void destroy() {
82          logService = null;
83          logServiceTracker.close();
84      }
85  
86      @Override
87      public InternalLogger newInstance(String name) {
88          return new OsgiLogger(this, name, fallback.newInstance(name));
89      }
90  }