001/*
002The contents of this file are subject to the Mozilla Public License Version 1.1 
003(the "License"); you may not use this file except in compliance with the License. 
004You may obtain a copy of the License at http://www.mozilla.org/MPL/ 
005Software distributed under the License is distributed on an "AS IS" basis, 
006WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the 
007specific language governing rights and limitations under the License. 
008
009The Original Code is "MLLPTransport.java".  Description: 
010"An implementation of the HL7 Minimal Lower Layer Protocol." 
011
012The Initial Developer of the Original Code is University Health Network. Copyright (C) 
0132004.  All Rights Reserved. 
014
015Contributor(s): ______________________________________. 
016
017Alternatively, the contents of this file may be used under the terms of the 
018GNU General Public License (the "GPL"), in which case the provisions of the GPL are 
019applicable instead of those above.  If you wish to allow use of your version of this 
020file only under the terms of the GPL and not to allow others to use your version 
021of this file under the MPL, indicate your decision by deleting  the provisions above 
022and replace  them with the notice and other provisions required by the GPL License.  
023If you do not delete the provisions above, a recipient may use your version of 
024this file under either the MPL or the GPL. 
025*/
026
027package ca.uhn.hl7v2.protocol.impl;
028
029import java.io.IOException;
030import java.io.InputStream;
031import java.util.Properties;
032
033import ca.uhn.hl7v2.llp.LLPException;
034import ca.uhn.hl7v2.llp.MinLLPReader;
035import ca.uhn.hl7v2.llp.MinLLPWriter;
036import ca.uhn.hl7v2.protocol.StreamSource;
037import ca.uhn.hl7v2.protocol.TransportException;
038import ca.uhn.hl7v2.protocol.TransportLayer;
039import ca.uhn.hl7v2.protocol.Transportable;
040
041/**
042 * An implementation of the HL7 Minimal Lower Layer Protocol (see 
043 * HL7 implementation guide appendix C).  Note that this is the most common 
044 * protocol used in HL7 interfaces.  
045 * 
046 * @author <a href="mailto:bryan.tripp@uhn.on.ca">Bryan Tripp</a>
047 * @version $Revision: 1.1 $ updated on $Date: 2007-02-19 02:24:26 $ by $Author: jamesagnew $
048 */
049public class MLLPTransport extends AbstractTransport implements TransportLayer {
050
051    private MinLLPReader myReader;
052    private MinLLPWriter myWriter;
053    
054    private final StreamSource myStreamSource;
055    private final Properties myCharsetMappings;
056    
057    /**
058     * @param theStreamSource the provider of input and output streams connected
059     *      to the remote server 
060     */
061    public MLLPTransport(StreamSource theStreamSource) throws TransportException {
062        myStreamSource = theStreamSource;
063        myCharsetMappings = loadCharsetMappings();
064    }
065    
066    private static Properties loadCharsetMappings() throws TransportException {
067        Properties mappings = new Properties();
068        String resource = "ca/uhn/hl7v2/protocol/impl/charset_map.properties";
069        InputStream in = MLLPTransport.class.getClassLoader().getResourceAsStream(resource);
070        try {
071            mappings.load(in);
072        } catch (IOException e) {
073            throw new TransportException("Can't load character set mappings from " + resource, e);
074        }
075        return mappings;        
076    }
077
078    public void doSend(Transportable theMessage) throws TransportException {
079        try {
080            String charset = (String) theMessage.getMetadata().get("MSH-18");
081            if (charset != null) {
082                charset = myCharsetMappings.getProperty(charset, charset); //default to self if no match
083                myWriter.writeMessage(theMessage.getMessage(), charset); 
084            } else {
085                myWriter.writeMessage(theMessage.getMessage());
086            }
087        } catch (LLPException | IOException e) {
088            throw new TransportException(e);
089        }
090    }
091
092    /** 
093     * @see ca.uhn.hl7v2.protocol.impl.AbstractTransport#doReceive()
094     */
095    public Transportable doReceive() throws TransportException {
096        Transportable result = null;
097        try {
098            String message = myReader.getMessage();
099            if (message != null) {
100                result = new TransportableImpl(message);                
101            }
102        } catch (LLPException | IOException e) {
103            throw new TransportException(e);
104        }
105        return result;
106    }
107
108    public void doConnect() throws TransportException {
109        myStreamSource.connect();
110        try {
111            myReader = new MinLLPReader(myStreamSource.getInboundStream());
112            myWriter = new MinLLPWriter(myStreamSource.getOutboundStream());
113        } catch (IOException e) {
114            throw new TransportException(e);
115        } 
116    }
117
118    /**
119     * @see ca.uhn.hl7v2.protocol.TransportLayer#disconnect()
120     */
121    public void doDisconnect() throws TransportException {
122        try {
123            if (myReader != null) myReader.close();
124            if (myWriter != null) myWriter.close();
125        } catch (IOException e) {
126            throw new TransportException(e);
127        } finally {
128            myReader = null;
129            myWriter = null;
130        }        
131        myStreamSource.disconnect();
132    }
133    
134}