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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 "AbstactTransport.java".  Description: 
10  "A base implementation of TransportLayer." 
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.util.HashMap;
30  import java.util.Map;
31  
32  import org.slf4j.Logger;
33  import org.slf4j.LoggerFactory;
34  
35  import ca.uhn.hl7v2.protocol.TransportException;
36  import ca.uhn.hl7v2.protocol.TransportLayer;
37  import ca.uhn.hl7v2.protocol.Transportable;
38  
39  /**
40   * A base implementation of <code>TransportLayer</code> which looks after the 
41   * addition of common metadata to each inbound <code>Transportable</code>.
42   *   
43   * @author <a href="mailto:bryan.tripp@uhn.on.ca">Bryan Tripp</a>
44   * @version $Revision: 1.1 $ updated on $Date: 2007-02-19 02:24:26 $ by $Author: jamesagnew $
45   */
46  public abstract class AbstractTransport implements TransportLayer {
47      
48      private static Logger log = LoggerFactory.getLogger(AbstractTransport.class);
49      
50      private Map<String, Object> myCommonMetadata;
51      private boolean myIsConnected = false;
52      
53      public AbstractTransport() {
54          myCommonMetadata = new HashMap<String, Object>();
55      }
56          
57      /**
58       * @see ca.uhn.hl7v2.protocol.TransportLayer#getCommonMetadata()
59       */
60      public Map<String, Object> getCommonMetadata() {
61          return myCommonMetadata;
62      }
63  
64      /**
65       * Delegates to <code>doReceive()</code> and adds common metadata
66       * to the resulting <code>Transportable</code> before it is returned.
67       */
68      public Transportable receive() throws TransportException {
69          if (!isConnected()) {
70              throw new TransportException("Can't receive because TransportLayer is not connected");
71          }
72          
73          Transportable message = doReceive();
74          if (message != null) {
75              message.getMetadata().putAll(myCommonMetadata);
76          }
77          
78          log.debug("Received: {} ", (message == null ? null : message.getMessage()));
79               
80          return message;
81      }
82  
83      /**
84       * Called by receive(), which then adds common metadata.   
85       * 
86       * @return Transportable the next available message 
87       * @throws TransportException
88       */    
89      public abstract Transportable doReceive() throws TransportException;
90      
91      /**
92       * Delegates to <code>doSend()</code> after checking that we are connected. 
93       * 
94       * @see ca.uhn.hl7v2.protocol.TransportLayer#send(Transportable) 
95       */
96      public void send(Transportable theMessage) throws TransportException {
97          if (!isConnected()) {
98              throw new TransportException("Can't send because TransportLayer is not connected");
99          }
100         
101         doSend(theMessage);
102         
103         log.debug("Sent: {}", (theMessage == null ? null : theMessage.getMessage()));
104     }
105     
106     /**
107      * The method send() delegates to this method after checking whether we are 
108      * connected.   
109      * @param theMessage
110      * @throws TransportException
111      */
112     public abstract void doSend(Transportable theMessage) throws TransportException;
113     
114     /**
115      * Sets isConnected() to false, then calls doConnect(), then sets isConnected() to 
116      * true. 
117      * @see ca.uhn.hl7v2.protocol.TransportLayer#connect()  
118      */
119     public void connect() throws TransportException {
120         myIsConnected = false;
121         doConnect();
122         myIsConnected = true;
123     }
124     
125     /**
126      * Performs connection as described in TransportLayer.connect().  The 
127      * connect() method of this class delegates to doConnect() after some
128      * internal housekeeping.
129      *   
130      * @throws TransportException
131      */
132     public abstract void doConnect() throws TransportException;
133     
134     /**
135      * @see ca.uhn.hl7v2.protocol.TransportLayer#isConnected()  
136      */
137     public boolean isConnected() {
138         return myIsConnected;
139     }
140     
141     /**
142      * @see ca.uhn.hl7v2.protocol.TransportLayer#disconnect()
143      */
144     public void disconnect() throws TransportException {
145         myIsConnected = false;
146         doDisconnect();
147     }
148     
149     /**
150      * Performs disconnection as described in TransportLayer.disconnect().  The 
151      * disconnect() method of this class delegates to doDisconnect() after some
152      * internal housekeeping.
153      *   
154      * @throws TransportException
155      */
156     public abstract void doDisconnect() throws TransportException;
157     
158 }