org.argeo.slc.client.ui.dist/src/org/argeo/slc/client/ui/dist/utils/VersionComparator.java

   1 package org.argeo.slc.client.ui.dist.utils;
   2
   3 import org.eclipse.jface.viewers.Viewer;
   4 import org.eclipse.jface.viewers.ViewerComparator;
   5
   6 /**
   7  * Enable comparison of two version string with form "1.2.5.qualifier" with
   8  * following rules and assumptions:
   9  * <ul>
  10  * <li>
  11  * Version are parsed and compared segment by segment; doing best effort to
  12  * convert major, minor and micro to integer and compare them as such (to have
  13  * 0.1 < 0.9 < 0.10 not 0.1 < 0.10 < 0.9).</li>
  14  * <li>Version should not contain any dash (-), version segments should be
  15  * separated by dots (.)</li>
  16  * </ul>
  17  */
  18
  19 public class VersionComparator extends ViewerComparator {
  20         private static final long serialVersionUID = 3760077835650538982L;
  21
  22         @Override
  23         public int compare(Viewer viewer, Object e1, Object e2) {
  24                 String s1 = (String) e1;
  25                 String s2 = (String) e2;
  26                 return compareVersion(s1, s2);
  27         }
  28
  29         /**
  30          * Enable comparison of two versions of the form
  31          * "major.minor.micro.qualifier". We assume the separator is always a "."
  32          * and make best effort to convert major, minor and micro to int.
  33          */
  34         private int compareVersion(String v1, String v2) {
  35                 String[] t1 = v1.split("\\.");
  36                 String[] t2 = v2.split("\\.");
  37
  38                 for (int i = 0; i < t1.length && i < t2.length; i++) {
  39                         int result = compareToken(t1[i], t2[i]);
  40                         if (result != 0)
  41                                 return result;
  42                 }
  43                 if (t1.length > t2.length)
  44                         return 1;
  45                 else if (t1.length < t2.length)
  46                         return -1;
  47                 else
  48                         return 0;
  49         }
  50
  51         private int compareToken(String t1, String t2) {
  52                 if (t1 == null && t2 == null)
  53                         return 0;
  54                 else if (t1 == null)
  55                         return -1;
  56                 else if (t2 == null)
  57                         return 1;
  58
  59                 Integer i1 = null, i2 = null;
  60                 try {
  61                         i1 = new Integer(t1);
  62                         i2 = new Integer(t2);
  63                 } catch (NumberFormatException nfe) {
  64                         // the format is not valid we silently compare as String
  65                         return t1.compareTo(t2);
  66                 }
  67                 return i1.compareTo(i2);
  68         }
  69 }