Coverage Report - ca.uhn.hl7v2.util.MessageIDGenerator
 
Classes in this File Line Coverage Branch Coverage Complexity
MessageIDGenerator
65%
34/52
50%
6/12
4.5
 
 1  
 package ca.uhn.hl7v2.util;
 2  
 
 3  
 import java.io.File;
 4  
 import java.io.FileNotFoundException;
 5  
 import java.io.FileReader;
 6  
 import java.io.FileWriter;
 7  
 import java.io.IOException;
 8  
 
 9  
 import org.slf4j.Logger;
 10  
 import org.slf4j.LoggerFactory;
 11  
 
 12  
 import ca.uhn.hl7v2.util.idgenerator.FileBasedHiLoGenerator;
 13  
 
 14  
 /**
 15  
  * <p>
 16  
  * Creates unique message IDs.  IDs are stored in a file called {@link Home#getHomeDirectory() hapi.home}/id_file for persistence
 17  
  * across JVM sessions.  Note that if one day you run the JVM with a new working directory,
 18  
  * you must move or copy id_file into this directory so that new ID numbers will begin
 19  
  * with the last one used, rather than starting over again.
 20  
  * </p>
 21  
  * <p>
 22  
  * Note that as of HAPI 2.0, by default this class will not fail even if the id_file can
 23  
  * not be read/written. In this case, HAPI will try to fail gracefully by simply generating
 24  
  * a numeric sequence starting at zero. This behaviour can be overwritten using 
 25  
  * {@link #NEVER_FAIL_PROPERTY}
 26  
  * </p>
 27  
  * Note: you should not use this class directory, but use the {@link IDGeneratorFactory} instead. 
 28  
  * Also consider using {@link FileBasedHiLoGenerator} which provides better performance
 29  
  * 
 30  
  * 
 31  
  * @author Neal Acharya
 32  
  * @deprecated use one of the IDGenerator implementations
 33  
  */
 34  
 public class MessageIDGenerator {
 35  
     
 36  1
         private static final Logger ourLog = LoggerFactory.getLogger(MessageIDGenerator.class.getName());
 37  
     private static MessageIDGenerator messageIdGenerator;
 38  
     
 39  
     /**
 40  
      * Contains the complete path to the default ID file, which is a plain text file containing
 41  
      * the number corresponding to the last generated ID
 42  
      */
 43  1
     public final static String DEFAULT_ID_FILE = Home.getHomeDirectory().getAbsolutePath() + "/id_file";
 44  
     
 45  
     /**
 46  
      * System property key which indicates that this class should never fail. If this
 47  
      * system property is set to false (default is true), as in the following code:<br>
 48  
      * <code>System.setProperty(MessageIDGenerator.NEVER_FAIL_PROPERTY, Boolean.FALSE.toString());</code><br>
 49  
      * this class will fail if the underlying disk file can not be
 50  
      * read or written. This means you are roughly guaranteed a unique
 51  
      * ID number between JVM sessions (barring the file getting lost or corrupted). 
 52  
      */
 53  1
     public static final String NEVER_FAIL_PROPERTY = MessageIDGenerator.class.getName() + "_NEVER_FAIL_PROPERTY";
 54  
     
 55  
     private long id;
 56  
     private FileWriter fileW;
 57  
     
 58  
     /**
 59  
      * Constructor
 60  
      * Creates an instance of the class
 61  
      * Its reads an id (longint#) from an external file, if one is not present then the external file
 62  
      * is created and initialized to zero.
 63  
      * This id is stored into the private field of id.
 64  
      */
 65  1
     private  MessageIDGenerator() throws IOException {
 66  1
         initialize();
 67  1
     }//end constructor code
 68  
 
 69  
     
 70  
         /**
 71  
          * Force the generator to re-load the ID file and initialize itself.
 72  
          * 
 73  
          * This method is mostly provided as a convenience to unit tests, and does
 74  
          * not normally need to be called.
 75  
          */
 76  
     void initialize() throws IOException {
 77  2
             id = 0;
 78  
             
 79  
                 /*check external file for the last value unique id value generated by
 80  
         this class*/
 81  
         try{
 82  
             // We should check to see if the external file for storing the unique ids exists
 83  2
             File extFile = new File(DEFAULT_ID_FILE);
 84  2
             if (extFile.createNewFile()== true){
 85  
                 /*there was no existing file so a new one has been created with createNewFile method.  The
 86  
                 file is stored at  <hapi.home>/id_file.txt */
 87  
                 // We can simply initialize the private id field to zero
 88  0
                 id = 0;
 89  
                 
 90  
             }//end if
 91  
             else{
 92  
                 /*The file does exist which is why we received false from the
 93  
                 createNewFile method. We should now try to read from this file*/
 94  2
                 FileReader fileR = new FileReader(DEFAULT_ID_FILE);
 95  2
                 char[] charArray = new char[100];
 96  2
                 int e = fileR.read(charArray);
 97  2
                 if (e <= 0){
 98  
                     /*We know the file exists but it has no value stored in it. So at this point we can simply initialize the
 99  
                     private id field to zero*/
 100  1
                     id = 0;
 101  
                 }//end if
 102  
                 else{
 103  
                     /* Here we know that the file exists and has a stored value. we should read this value and set the
 104  
                     private id field to it*/
 105  1
                     String idStr = String.valueOf(charArray);
 106  1
                     String idStrTrim = idStr.trim();
 107  
                     
 108  
                     try {
 109  1
                             id = Long.parseLong(idStrTrim);
 110  0
                     } catch (NumberFormatException nfe) {
 111  0
                             ourLog.warn("Failed to parse message ID file value \"" + idStrTrim + "\". Defaulting to 0.");
 112  1
                     }
 113  
                     
 114  
                 }//end else
 115  
                 //Fix for bug 1100881:  Close the file after writing.
 116  2
                 fileR.close();
 117  
             }//end else
 118  0
         } catch (FileNotFoundException e) {
 119  0
             ourLog.error("Failed to locate message ID file. Message was: {}", e.getMessage());
 120  0
         } catch (IOException e) {
 121  0
                 if (Boolean.TRUE.equals(System.getProperty(NEVER_FAIL_PROPERTY, Boolean.TRUE.toString()))) {
 122  0
                         ourLog.warn("Could not retrieve message ID file, going to default to ID of 0. Message was: {}", e.getMessage());
 123  0
                         id = 0;
 124  0
                         return;
 125  
                 } else {
 126  0
                         throw e;
 127  
                 }
 128  2
         }
 129  2
         }
 130  
     
 131  
     /**
 132  
      * Synchronized method used to return the single (static) instance of the class
 133  
      */
 134  
     public static synchronized MessageIDGenerator getInstance() throws IOException {
 135  1203
         if (messageIdGenerator == null)
 136  1
             messageIdGenerator = new MessageIDGenerator();
 137  1203
         return messageIdGenerator;
 138  
     }//end method
 139  
     
 140  
     /**
 141  
      * Synchronized method used to return the incremented id value
 142  
      */
 143  
     public synchronized String getNewID() throws IOException{
 144  
             try {
 145  
                     //increment the private field
 146  1203
                 id = id + 1;
 147  
                 //write the id value to the file
 148  1203
                 String idStr = String.valueOf(id);
 149  
 
 150  
                 //create an instance of the Filewriter Object pointing to "C:\\extfiles\\Idfile.txt"
 151  1203
                 fileW = new FileWriter(DEFAULT_ID_FILE, false);
 152  1202
                 fileW.write(idStr);
 153  1202
                 fileW.flush();
 154  1202
                 fileW.close();
 155  1
             } catch (FileNotFoundException e) {
 156  1
                 if (Boolean.TRUE.equals(System.getProperty(NEVER_FAIL_PROPERTY, Boolean.TRUE.toString()))) {
 157  0
                         ourLog.info("Failed to create message ID file. Message was: {}", e.getMessage());
 158  0
                         fileW = null;
 159  
                 }
 160  0
             } catch (IOException e) {
 161  0
                 if (Boolean.TRUE.equals(System.getProperty(NEVER_FAIL_PROPERTY, Boolean.TRUE.toString()))) {
 162  0
                         ourLog.debug("Failed to create message ID file. Message was: {}", e.getMessage());
 163  0
                         fileW = null;
 164  
                 } else {
 165  0
                         throw e;
 166  
                 }
 167  1203
             }
 168  1203
             return String.valueOf(id);
 169  
     }//end method
 170  
     
 171  
 }