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1   /**
2    * The contents of this file are subject to the Mozilla Public License Version 1.1
3    * (the "License"); you may not use this file except in compliance with the License.
4    * You may obtain a copy of the License at http://www.mozilla.org/MPL/
5    * Software distributed under the License is distributed on an "AS IS" basis,
6    * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the
7    * specific language governing rights and limitations under the License.
8    *
9    * The Original Code is "Receiver.java".  Description:
10   * "Listens for incoming messages on a certain input stream, and
11   * sends them to the appropriate location."
12   *
13   * The Initial Developer of the Original Code is University Health Network. Copyright (C)
14   * 2002.  All Rights Reserved.
15   *
16   * Contributor(s): _____________.
17   *
18   * Alternatively, the contents of this file may be used under the terms of the
19   * GNU General Public License (the "GPL"), in which case the provisions of the GPL are
20   * applicable instead of those above.  If you wish to allow use of your version of this
21   * file only under the terms of the GPL and not to allow others to use your version
22   * of this file under the MPL, indicate your decision by deleting  the provisions above
23   * and replace  them with the notice and other provisions required by the GPL License.
24   * If you do not delete the provisions above, a recipient may use your version of
25   * this file under either the MPL or the GPL.
26   */
27  
28  package ca.uhn.hl7v2.app;
29  
30  import java.io.IOException;
31  import java.net.SocketException;
32  
33  import org.slf4j.Logger;
34  import org.slf4j.LoggerFactory;
35  
36  import ca.uhn.hl7v2.concurrent.Service;
37  import ca.uhn.hl7v2.llp.HL7Reader;
38  
39  /**
40   * Listens for incoming messages on a certain input stream, and sends them to
41   * the appropriate location.
42   * 
43   * @author Bryan Tripp
44   */
45  public class Receiver extends Service {
46  
47  	private static final Logger log = LoggerFactory.getLogger(Receiver.class);
48  
49  	private Connection conn;
50  	private HL7Reader in;
51  
52  	/** Creates a new instance of Receiver, associated with the given Connection */
53  	public Receiver(Connection c, HL7Reader in) {
54  		super("Receiver", c.getExecutorService());
55  		this.conn = c;
56  		this.in = in;
57  	}
58  
59  
60  	@Override
61  	protected void handle() {
62  		try {
63  			String message = in.getMessage();
64  			if (message == null) {
65  				log.debug("Failed to read a message");
66  			} else {
67  				processMessage(message);
68  			}
69  		} catch (SocketException e)  {
70  			// This probably means that the client closed the server connection normally
71  			conn.close();
72  			log.info("SocketException: closing Connection, will no longer read messages with this Receiver: " + e.getMessage());
73  		} catch (IOException e) {
74  			conn.close();
75  			log.warn("IOException: closing Connection, will no longer read messages with this Receiver. ", e);
76  		} catch (Exception e) {
77  			log.error("Error while closing connection: ", e);
78  		}
79  
80  	}
81  
82  
83  	/**
84  	 * Processes a single incoming message by sending it to the appropriate
85  	 * internal location. If an incoming message contains an MSA-2 field, it is
86  	 * assumed that this message is meant as a reply to a message that has been
87  	 * sent earlier. In this case an attempt is give the message to the object
88  	 * that sent the corresponding outbound message. If the message contains an
89  	 * MSA-2 but there are no objects that appear to be waiting for it, it is
90  	 * discarded and an exception is logged. If the message does not contain an
91  	 * MSA-2 field, it is concluded that the message has arrived unsolicited. In
92  	 * this case it is sent to the Responder (in a new Thread).
93  	 */
94  	protected void processMessage(String message) {
95  		String ackID = conn.getParser().getAckID(message);
96  		if (ackID == null) {
97  			log.debug("Unsolicited Message Received: {}", message);
98  			getExecutorService().submit(new Grunt(conn, message));
99  		} else {
100 			if (!conn.isRecipientWaiting(ackID, message)) {
101 				log.info("Unexpected Message Received. This message appears to be an acknowledgement (MSA-2 has a value) so it will be ignored: {}", message);
102 			} else {
103 				log.debug("Response Message Received: {}", message);
104 			}
105 		}
106 	}
107 
108 	/** Independent thread for processing a single message */
109 	private class Grunt implements Runnable {
110 
111 		private Connection conn;
112 		private String m;
113 
114 		public Grunt(Connection conn, String message) {
115 			this.conn = conn;
116 			this.m = message;
117 		}
118 
119 		public void run() {
120 			try {
121 				String response = conn.getResponder().processMessage(m);
122 				conn.getAckWriter().writeMessage(response);
123 			} catch (Exception e) {
124 				log.error("Error while processing message: ", e);
125 			}
126 		}
127 	}
128 
129 }