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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements. See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache license, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License. You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the license for the specific language governing permissions and
15   * limitations under the license.
16   */
17  package org.apache.logging.log4j.core.net.jms;
18  
19  import java.io.Serializable;
20  
21  import javax.jms.JMSException;
22  import javax.jms.ObjectMessage;
23  import javax.naming.Context;
24  import javax.naming.NameNotFoundException;
25  import javax.naming.NamingException;
26  
27  import org.apache.logging.log4j.LogManager;
28  import org.apache.logging.log4j.Logger;
29  import org.apache.logging.log4j.core.LogEvent;
30  import org.apache.logging.log4j.core.LogEventListener;
31  
32  /**
33   * Abstract base class for receiving LogEvents over JMS. This class expects all messages to be serialized log events.
34   */
35  public abstract class AbstractJmsReceiver extends LogEventListener implements javax.jms.MessageListener {
36  
37      /**
38       * Logger to capture diagnostics.
39       */
40      protected Logger logger = LogManager.getLogger(this.getClass().getName());
41  
42      /**
43       * Listener that receives the event.
44       * @param message The received message.
45       */
46      @Override
47      public void onMessage(final javax.jms.Message message) {
48          try {
49              if (message instanceof ObjectMessage) {
50                  final ObjectMessage objectMessage = (ObjectMessage) message;
51                  final Serializable object = objectMessage.getObject();
52                  if (object instanceof LogEvent) {
53                      log((LogEvent) object);
54                  } else {
55                      logger.warn("Received message is of type " + object.getClass().getName() + ", was expecting LogEvent.");
56                  }
57              } else {
58                  logger.warn("Received message is of type " + message.getJMSType()
59                      + ", was expecting ObjectMessage.");
60              }
61          } catch (final JMSException jmse) {
62              logger.error("Exception thrown while processing incoming message.",
63                  jmse);
64          }
65      }
66  
67      /**
68       * Looks up an object from the Context.
69       * @param ctx The Context.
70       * @param name The name of the object to locate.
71       * @return The object.
72       * @throws NamingException if an error occurs.
73       */
74      protected Object lookup(final Context ctx, final String name) throws NamingException {
75          try {
76              return ctx.lookup(name);
77          } catch (final NameNotFoundException e) {
78              logger.error("Could not find name [" + name + "].");
79              throw e;
80          }
81      }
82  
83  }