Coverage Report - ca.uhn.hl7v2.util.idgenerator.HiLoGenerator
 
Classes in this File Line Coverage Branch Coverage Complexity
HiLoGenerator
100%
20/20
100%
4/4
1.286
 
 1  
 /**
 2  
 The contents of this file are subject to the Mozilla Public License Version 1.1 
 3  
 (the "License"); you may not use this file except in compliance with the License. 
 4  
 You may obtain a copy of the License at http://www.mozilla.org/MPL/ 
 5  
 Software distributed under the License is distributed on an "AS IS" basis, 
 6  
 WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the 
 7  
 specific language governing rights and limitations under the License. 
 8  
 
 9  
 The Original Code is "HiLoGenerator.java".  Description: 
 10  
 "Abstract base class for HiLo ID Generators" 
 11  
 
 12  
 The Initial Developer of the Original Code is University Health Network. Copyright (C) 
 13  
 2001.  All Rights Reserved. 
 14  
 
 15  
 Contributor(s): ______________________________________. 
 16  
 
 17  
 Alternatively, the contents of this file may be used under the terms of the 
 18  
 GNU General Public License (the  "GPL"), in which case the provisions of the GPL are 
 19  
 applicable instead of those above.  If you wish to allow use of your version of this 
 20  
 file only under the terms of the GPL and not to allow others to use your version 
 21  
 of this file under the MPL, indicate your decision by deleting  the provisions above 
 22  
 and replace  them with the notice and other provisions required by the GPL License.  
 23  
 If you do not delete the provisions above, a recipient may use your version of 
 24  
 this file under either the MPL or the GPL. 
 25  
  */
 26  
 package ca.uhn.hl7v2.util.idgenerator;
 27  
 
 28  
 import java.io.IOException;
 29  
 
 30  
 import org.slf4j.Logger;
 31  
 import org.slf4j.LoggerFactory;
 32  
 
 33  
 /**
 34  
  * Abstract base class for a HiLo-style generator that cheaply generates "lo"
 35  
  * IDs in memory but only seldomly increments (potentially more expensive) a
 36  
  * "hi" ID, e.g. in a persistent store. The combination of "lo" and "hi" ID
 37  
  * becomes the final ID returned to the caller.
 38  
  * 
 39  
  * @author Christian Ohr
 40  
  */
 41  5530
 public abstract class HiLoGenerator extends IDGenerator.OrderedSupport {
 42  
 
 43  10
         private static final Logger LOG = LoggerFactory
 44  5
                         .getLogger(HiLoGenerator.class.getName());
 45  
 
 46  5530
         private long lo = 0L;
 47  5530
         private long base = -1L;
 48  
 
 49  
         public synchronized String getID() throws IOException {
 50  7433
                 if (base < 0) {
 51  830
                         LOG.debug("Obtain next hi ID");
 52  830
                         base = nextBase();
 53  
                 }
 54  7433
                 if (getNextLoId() >= getMaxLo()) {
 55  60
                         LOG.debug("Obtain next hi ID");
 56  60
                         base = nextBase();
 57  
                 }
 58  7433
                 return Long.toString(base + lo);
 59  
         }
 60  
 
 61  
         private long nextBase() throws IOException {
 62  890
         long base = getNextHiId();
 63  890
                 lo = 0;
 64  890
                 return base;
 65  
         }
 66  
 
 67  
     /**
 68  
      * Returns the next Hi ID
 69  
      * @return the next Hi ID
 70  
      * @throws IOException
 71  
      */
 72  
         protected abstract long getNextHiId() throws IOException;
 73  
 
 74  
     /**
 75  
      * Resets the Hi ID
 76  
      */
 77  
         protected abstract void resetHiId();
 78  
 
 79  
     /**
 80  
      * Returns then next Lo ID
 81  
      * @return
 82  
      */
 83  
         protected long getNextLoId() {
 84  7433
                 return ++lo;
 85  
         }
 86  
 
 87  
     /**
 88  
      * Resets the generator
 89  
      */
 90  
         public void reset() {
 91  10
                 lo = 0;
 92  10
                 base = -1;
 93  10
                 resetHiId();
 94  10
         }
 95  
 
 96  
     /**
 97  
      * Returns the maximum Lo ID (expect the Hi ID be incremented afterwards)
 98  
      * @return the maximum Lo ID
 99  
      */
 100  
         abstract public long getMaxLo();
 101  
 
 102  
 }