001/**
002 * The 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.
004 * You may obtain a copy of the License at http://www.mozilla.org/MPL/
005 * Software distributed under the License is distributed on an "AS IS" basis,
006 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the
007 * specific language governing rights and limitations under the License.
008 *
009 * The Original Code is "Receiver.java".  Description:
010 * "Listens for incoming messages on a certain input stream, and
011 * sends them to the appropriate location."
012 *
013 * The Initial Developer of the Original Code is University Health Network. Copyright (C)
014 * 2002.  All Rights Reserved.
015 *
016 * Contributor(s): _____________.
017 *
018 * Alternatively, the contents of this file may be used under the terms of the
019 * GNU General Public License (the "GPL"), in which case the provisions of the GPL are
020 * applicable instead of those above.  If you wish to allow use of your version of this
021 * file only under the terms of the GPL and not to allow others to use your version
022 * of this file under the MPL, indicate your decision by deleting  the provisions above
023 * and replace  them with the notice and other provisions required by the GPL License.
024 * If you do not delete the provisions above, a recipient may use your version of
025 * this file under either the MPL or the GPL.
026 */
027
028package ca.uhn.hl7v2.app;
029
030import java.io.IOException;
031import java.net.SocketException;
032
033import org.slf4j.Logger;
034import org.slf4j.LoggerFactory;
035
036import ca.uhn.hl7v2.concurrent.Service;
037import ca.uhn.hl7v2.llp.HL7Reader;
038
039/**
040 * Listens for incoming messages on a certain input stream, and sends them to
041 * the appropriate location.
042 * 
043 * @author Bryan Tripp
044 */
045public class Receiver extends Service {
046
047        private static final Logger log = LoggerFactory.getLogger(Receiver.class);
048
049        private Connection conn;
050        private HL7Reader in;
051
052        /** Creates a new instance of Receiver, associated with the given Connection */
053        public Receiver(Connection c, HL7Reader in) {
054                super("Receiver", c.getExecutorService());
055                this.conn = c;
056                this.in = in;
057        }
058
059
060        @Override
061        protected void handle() {
062                try {
063                        String message = in.getMessage();
064                        if (message == null) {
065                                log.debug("Failed to read a message");
066                        } else {
067                                processMessage(message);
068                        }
069                } catch (SocketException e)  {
070                        // This probably means that the client closed the server connection normally
071                        conn.close();
072                        log.info("SocketException: closing Connection, will no longer read messages with this Receiver: " + e.getMessage());
073                } catch (IOException e) {
074                        conn.close();
075                        log.warn("IOException: closing Connection, will no longer read messages with this Receiver. ", e);
076                } catch (Exception e) {
077                        log.error("Error while closing connection: ", e);
078                }
079
080        }
081
082
083        /**
084         * Processes a single incoming message by sending it to the appropriate
085         * internal location. If an incoming message contains an MSA-2 field, it is
086         * assumed that this message is meant as a reply to a message that has been
087         * sent earlier. In this case an attempt is give the message to the object
088         * that sent the corresponding outbound message. If the message contains an
089         * MSA-2 but there are no objects that appear to be waiting for it, it is
090         * discarded and an exception is logged. If the message does not contain an
091         * MSA-2 field, it is concluded that the message has arrived unsolicited. In
092         * this case it is sent to the Responder (in a new Thread).
093         */
094        protected void processMessage(String message) {
095                String ackID = conn.getParser().getAckID(message);
096                if (ackID == null) {
097                        log.debug("Unsolicited Message Received: {}", message);
098                        getExecutorService().submit(new Grunt(conn, message));
099                } else {
100                        if (!conn.isRecipientWaiting(ackID, message)) {
101                                log.info("Unexpected Message Received: {}", 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}