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 "ApplicationLoader.java".  Description: 
010    "A utility for loading Application bindings from configuration files." 
011    
012    The Initial Developer of the Original Code is University Health Network. Copyright (C) 
013    2004.  All Rights Reserved. 
014    
015    Contributor(s): ______________________________________. 
016    
017    Alternatively, the contents of this file may be used under the terms of the 
018    GNU General Public License (the  ?GPL?), in which case the provisions of the GPL are 
019    applicable instead of those above.  If you wish to allow use of your version of this 
020    file only under the terms of the GPL and not to allow others to use your version 
021    of this file under the MPL, indicate your decision by deleting  the provisions above 
022    and replace  them with the notice and other provisions required by the GPL License.  
023    If you do not delete the provisions above, a recipient may use your version of 
024    this file under either the MPL or the GPL. 
025    */
026    
027    package ca.uhn.hl7v2.protocol.impl;
028    
029    import java.io.BufferedReader;
030    import java.io.IOException;
031    import java.io.InputStreamReader;
032    import java.net.URL;
033    import java.util.NoSuchElementException;
034    import java.util.StringTokenizer;
035    
036    import ca.uhn.hl7v2.HL7Exception;
037    import ca.uhn.hl7v2.app.Application;
038    import ca.uhn.hl7v2.protocol.ApplicationRouter;
039    import ca.uhn.hl7v2.protocol.ReceivingApplication;
040    
041    /**
042     * A utility for loading <code>Applicaiton</code> and <code>ReceivingApplication</code> bindings 
043     * from configuration files.  
044     *  
045     * @author <a href="mailto:bryan.tripp@uhn.on.ca">Bryan Tripp</a>
046     * @version $Revision: 1.1 $ updated on $Date: 2007/02/19 02:24:26 $ by $Author: jamesagnew $
047     */
048    public class ApplicationLoader {
049    
050        /**
051         * <p>A convenience method for binding applications to an <code>ApplicationRouter</code>
052         * Information about bindings is read from a file at a specified URL.  Each line in the 
053         * file should have the following format (entries TAB delimited):</p>
054         * 
055         * <p>message_type &#009; trigger_event &#009; processing_id &#009; version_id &#009; app_class</p>
056         * 
057         * <p>Note that the first four fields can be the wildcard "*", which means any.</p>
058         * 
059         * <p>For example, if you write an Application called org.yourorganiztion.ADTProcessor
060         * that processes several types of ADT messages, and another called 
061         * org.yourorganization.ResultProcessor that processes result messages, you might have a 
062         * file that looks like this: </p>
063         * 
064         * <p>ADT &#009; * &#009; * &#009; * &#009; org.yourorganization.ADTProcessor<br>
065         * ORU &#009; R01 &#009; * &#009; * &#009; org.yourorganization.ResultProcessor</p>
066         * 
067         * <p>Each class listed in this file must implement either ca.uhn.hl7v2.app.Application or 
068         * ca.uhn.hl7v2.protocol.ReceivingApplication, and must have a zero-argument constructor.</p>
069         * 
070         * @param theRouter the <code>ApplicationRouter</code> on which to make the binding
071         * @param theSource a URL pointing to the bindings file 
072         */
073        public static void loadApplications(ApplicationRouter theRouter, URL theSource)
074            throws IOException, HL7Exception, ClassNotFoundException, InstantiationException, IllegalAccessException {
075            
076            if (theSource == null) {
077                throw new HL7Exception("Can't load application bindings: the given URL is null");
078            }
079            
080            BufferedReader in = new BufferedReader(new InputStreamReader(theSource.openStream()));
081            String line = null;
082            while ((line = in.readLine()) != null) {
083                //parse application registration information 
084                StringTokenizer tok = new StringTokenizer(line, "\t", false);
085                String type = null, event = null, procId = null, verId = null, className = null;
086    
087                if (tok.hasMoreTokens()) { //skip blank lines 
088                    try {
089                        type = tok.nextToken();
090                        event = tok.nextToken();
091                        procId = tok.nextToken();
092                        verId = tok.nextToken();
093                        className = tok.nextToken();
094                    }
095                    catch (NoSuchElementException ne) {
096                        throw new HL7Exception(
097                            "Can't register applications from "
098                                + theSource.toExternalForm()
099                                + ". The line '"
100                                + line
101                                + "' is not of the form: message_type [tab] trigger_event " 
102                                + "[tab] processing ID [tab] version ID [tab] application_class. "
103                                + "*** NOTE TWO NEW FIELDS AS OF HAPI 0.5 ****. ",
104                            HL7Exception.APPLICATION_INTERNAL_ERROR);
105                    }
106    
107                    Class appClass = Class.forName(className); //may throw ClassNotFoundException 
108                    Object appObject = appClass.newInstance();
109                    ReceivingApplication app = null;
110                    if (appObject instanceof ReceivingApplication) {
111                        app = (ReceivingApplication) appObject;
112                    } else if (appObject instanceof Application) {
113                        app = new AppWrapper((Application) appObject);
114                    } else {
115                        throw new HL7Exception(
116                                "The specified class, " + appClass.getName() + 
117                                ", doesn't implement Application or ReceivingApplication.",
118                                HL7Exception.APPLICATION_INTERNAL_ERROR);   
119                    }
120    
121                    ApplicationRouter.AppRoutingData rd  
122                        = new AppRoutingDataImpl(type, event, procId, verId);                    
123                    theRouter.bindApplication(rd, app);
124                }
125            }
126        }    
127    }