utils/NameVersionComparator.java

   1 package org.argeo.slc.client.ui.dist.utils;
   2
   3 import org.argeo.eclipse.ui.TreeParent;
   4 import org.eclipse.jface.viewers.Viewer;
   5 import org.eclipse.jface.viewers.ViewerComparator;
   6
   7 /**
   8  * Enable comparison of two names version string with form org.argeo.slc-1.2.x.
   9  * with following rules and assumptions:
  10  * <ul>
  11  * <li>
  12  * Names are ordered using Lexicographical order</li>
  13  * <li>
  14  * Version are parsed and compared segment by segment; doing best effort to
  15  * convert major, minor and micro to integer and compare them as such (to have
  16  * 0.1 < 0.9 < 0.10 not 0.1 < 0.10 < 0.9).</li>
  17  * <li>Version should not contain any dash (-), version segments should be
  18  * separated by dots (.)</li>
  19  * </ul>
  20  */
  21
  22 public class NameVersionComparator extends ViewerComparator {
  23         private static final long serialVersionUID = 8290130681918221197L;
  24
  25         private VersionComparator vc = new VersionComparator();
  26
  27         @Override
  28         public int category(Object element) {
  29                 if (element instanceof String) {
  30                         int lastInd = ((String) element).lastIndexOf('-');
  31                         if (lastInd > 0)
  32                                 return 10;
  33                 }
  34                 // unvalid names always last
  35                 return 5;
  36         }
  37
  38         @Override
  39         public int compare(Viewer viewer, Object e1, Object e2) {
  40                 int cat1 = category(e1);
  41                 int cat2 = category(e2);
  42
  43                 if (cat1 != cat2) {
  44                         return cat1 - cat2;
  45                 }
  46
  47                 int result = 0;
  48
  49                 String s1, s2;
  50
  51                 if (e1 instanceof TreeParent) {
  52                         s1 = ((TreeParent) e1).getName();
  53                         s2 = ((TreeParent) e2).getName();
  54                 } else {
  55                         s1 = e1.toString();
  56                         s2 = e2.toString();
  57                 }
  58
  59                 int i1 = s1.lastIndexOf('-');
  60                 int i2 = s2.lastIndexOf('-');
  61
  62                 // Specific cases, unvalid Strings
  63                 if (i1 < 0)
  64                         if (i2 < 0)
  65                                 return s1.compareTo(s2);
  66                         else
  67                                 return 1;
  68                 else if (i2 < 0)
  69                         return -1;
  70
  71                 String aName = s1.substring(0, s1.lastIndexOf('-'));
  72                 String aVersion = s1.substring(s1.lastIndexOf('-'));
  73
  74                 String bName = s2.substring(0, s2.lastIndexOf('-'));
  75                 String bVersion = s2.substring(s2.lastIndexOf('-'));
  76
  77                 result = aName.compareTo(bName);
  78                 if (result != 0)
  79                         return result;
  80                 else
  81                         return vc.compare(viewer, aVersion, bVersion);
  82         }
  83 }