001    /*
002     * Created on 15-Apr-2004
003     */
004    package ca.uhn.hl7v2.protocol.impl;
005    
006    import java.io.IOException;
007    import java.io.InputStream;
008    import java.io.OutputStream;
009    import java.net.Socket;
010    
011    import ca.uhn.hl7v2.protocol.StreamSource;
012    import ca.uhn.hl7v2.protocol.TransportException;
013    
014    /**
015     * A base implementation of <code>StreamSource</code> based on sockets. 
016     *  
017     * @author <a href="mailto:bryan.tripp@uhn.on.ca">Bryan Tripp</a>
018     * @version $Revision: 1.1 $ updated on $Date: 2007-02-19 02:24:26 $ by $Author: jamesagnew $
019     */
020    public abstract class SocketStreamSource implements StreamSource {
021        
022        /**
023         * @return a socket from which input and output streams for message exchages 
024         *      are to be obtained    
025         */
026        public abstract Socket getSocket();
027        
028        /** 
029         * Gets fresh instance of socket, which is subsequently available 
030         * from <code>getSocket()</code>.  
031         */
032        public abstract void connect() throws TransportException;
033    
034        /**
035         * Closes streams and underlying socket. 
036         * @see ca.uhn.hl7v2.protocol.StreamSource#disconnect()
037         */
038        public void disconnect() throws TransportException {
039            try {
040                if (isConnected()) {
041                    getOutboundStream().close();
042                    getInboundStream().close();
043                    getSocket().close();
044                }            
045            } catch (IOException e) {
046                throw new TransportException(e);
047            }
048        }
049        
050        /**
051         * @return the stream to which we write outbound messages.   
052         */
053        public OutputStream getOutboundStream() throws TransportException {
054            checkConnected();
055            try {
056                return getSocket().getOutputStream();
057            } catch (IOException e) {
058                throw new TransportException(e); 
059            }
060        }
061        
062        private void checkConnected() throws TransportException {
063            if (!isConnected()) {
064                throw new TransportException("The socket is not connected");
065            }
066        }
067        
068        private boolean isConnected() {
069            boolean is = false;
070            if (getSocket() != null && getSocket().isConnected() && !getSocket().isClosed()) {
071                is = true;
072            }
073            return is;
074        }
075    
076        /**
077         * @return the stream to which we expect the remote server to send messages.  
078         */
079        public InputStream getInboundStream() throws TransportException {
080            checkConnected();
081            try {
082                return getSocket().getInputStream();
083            } catch (IOException e) {
084                throw new TransportException(e); 
085            }
086        }
087        
088    }