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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 "MLLPTransport.java".  Description: 
10  "An implementation of the HL7 Minimal Lower Layer Protocol." 
11  
12  The Initial Developer of the Original Code is University Health Network. Copyright (C) 
13  2004.  All Rights Reserved. 
14  
15  Contributor(s): ______________________________________. 
16  
17  Alternatively, the contents of this file may be used under the terms of the 
18  GNU General Public License (the "GPL"), in which case the provisions of the GPL are 
19  applicable instead of those above.  If you wish to allow use of your version of this 
20  file only under the terms of the GPL and not to allow others to use your version 
21  of this file under the MPL, indicate your decision by deleting  the provisions above 
22  and replace  them with the notice and other provisions required by the GPL License.  
23  If you do not delete the provisions above, a recipient may use your version of 
24  this file under either the MPL or the GPL. 
25  */
26  
27  package ca.uhn.hl7v2.protocol.impl;
28  
29  import java.io.IOException;
30  import java.io.InputStream;
31  import java.util.Properties;
32  
33  import ca.uhn.hl7v2.llp.LLPException;
34  import ca.uhn.hl7v2.llp.MinLLPReader;
35  import ca.uhn.hl7v2.llp.MinLLPWriter;
36  import ca.uhn.hl7v2.protocol.StreamSource;
37  import ca.uhn.hl7v2.protocol.TransportException;
38  import ca.uhn.hl7v2.protocol.TransportLayer;
39  import ca.uhn.hl7v2.protocol.Transportable;
40  
41  /**
42   * An implementation of the HL7 Minimal Lower Layer Protocol (see 
43   * HL7 implementation guide appendix C).  Note that this is the most common 
44   * protocol used in HL7 interfaces.  
45   * 
46   * @author <a href="mailto:bryan.tripp@uhn.on.ca">Bryan Tripp</a>
47   * @version $Revision: 1.1 $ updated on $Date: 2007-02-19 02:24:26 $ by $Author: jamesagnew $
48   */
49  public class MLLPTransport extends AbstractTransport implements TransportLayer {
50  
51      private MinLLPReader myReader;
52      private MinLLPWriter myWriter;
53      
54      private StreamSource myStreamSource;
55      private Properties myCharsetMappings;
56      
57      /**
58       * @param theStreamSource the provider of input and output streams connected
59       *      to the remote server 
60       */
61      public MLLPTransport(StreamSource theStreamSource) throws TransportException {
62          myStreamSource = theStreamSource;
63          myCharsetMappings = loadCharsetMappings();
64      }
65      
66      private static Properties loadCharsetMappings() throws TransportException {
67          Properties mappings = new Properties();
68          String resource = "ca/uhn/hl7v2/protocol/impl/charset_map.properties";
69          InputStream in = MLLPTransport.class.getClassLoader().getResourceAsStream(resource);
70          try {
71              mappings.load(in);
72          } catch (IOException e) {
73              throw new TransportException("Can't load character set mappings from " + resource, e);
74          }
75          return mappings;        
76      }
77  
78      /** 
79       * @see ca.uhn.hl7v2.protocol.AstractTransport#doSend(ca.uhn.hl7v2.protocol.Transportable)
80       */
81      public void doSend(Transportable theMessage) throws TransportException {
82          try {
83              String charset = (String) theMessage.getMetadata().get("MSH-18");
84              if (charset != null) {
85                  charset = myCharsetMappings.getProperty(charset, charset); //default to self if no match
86                  myWriter.writeMessage(theMessage.getMessage(), charset); 
87              } else {
88                  myWriter.writeMessage(theMessage.getMessage());
89              }
90          } catch (LLPException e) {
91              throw new TransportException(e);
92          } catch (IOException e) {
93              throw new TransportException(e);
94          }
95      }
96  
97      /** 
98       * @see ca.uhn.hl7v2.protocol.impl.AbstractTransport#doReceive()
99       */
100     public Transportable doReceive() throws TransportException {
101         Transportable result = null;
102         try {
103             String message = myReader.getMessage();
104             if (message != null) {
105                 result = new TransportableImpl(message);                
106             }
107         } catch (LLPException e) {
108             throw new TransportException(e);
109         } catch (IOException e) {
110             throw new TransportException(e);
111         }
112         return result;
113     }
114     
115     /**
116      * @see ca.uhn.hl7v2.protocol.AbstractTransport#doConnect()
117      */
118     public void doConnect() throws TransportException {
119         myStreamSource.connect();
120         try {
121             myReader = new MinLLPReader(myStreamSource.getInboundStream());
122             myWriter = new MinLLPWriter(myStreamSource.getOutboundStream());
123         } catch (IOException e) {
124             throw new TransportException(e);
125         } 
126     }
127 
128     /**
129      * @see ca.uhn.hl7v2.protocol.TransportLayer#disconnect()
130      */
131     public void doDisconnect() throws TransportException {
132         try {
133             if (myReader != null) myReader.close();
134             if (myWriter != null) myWriter.close();
135         } catch (IOException e) {
136             throw new TransportException(e);
137         } finally {
138             myReader = null;
139             myWriter = null;
140         }        
141         myStreamSource.disconnect();
142     }
143     
144 }