Clarify SLC project structure.

[gpl/argeo-slc.git] / cms / org.argeo.slc.client.ui.dist / src / org / argeo / slc / client / ui / dist / utils / VersionComparator.java

diff --git a/cms/org.argeo.slc.client.ui.dist/src/org/argeo/slc/client/ui/dist/utils/VersionComparator.java b/cms/org.argeo.slc.client.ui.dist/src/org/argeo/slc/client/ui/dist/utils/VersionComparator.java
new file mode 100644 (file)
index 0000000..34aff22
--- /dev/null
+++ b/cms/org.argeo.slc.client.ui.dist/src/org/argeo/slc/client/ui/dist/utils/VersionComparator.java
@@ -0,0 +1,69 @@
+package org.argeo.slc.client.ui.dist.utils;
+
+import org.eclipse.jface.viewers.Viewer;
+import org.eclipse.jface.viewers.ViewerComparator;
+
+/**
+ * Enable comparison of two version string with form "1.2.5.qualifier" with
+ * following rules and assumptions:
+ * <ul>
+ * <li>
+ * Version are parsed and compared segment by segment; doing best effort to
+ * convert major, minor and micro to integer and compare them as such (to have
+ * 0.1 < 0.9 < 0.10 not 0.1 < 0.10 < 0.9).</li>
+ * <li>Version should not contain any dash (-), version segments should be
+ * separated by dots (.)</li>
+ * </ul>
+ */
+
+public class VersionComparator extends ViewerComparator {
+       private static final long serialVersionUID = 3760077835650538982L;
+
+       @Override
+       public int compare(Viewer viewer, Object e1, Object e2) {
+               String s1 = (String) e1;
+               String s2 = (String) e2;
+               return compareVersion(s1, s2);
+       }
+
+       /**
+        * Enable comparison of two versions of the form
+        * "major.minor.micro.qualifier". We assume the separator is always a "."
+        * and make best effort to convert major, minor and micro to int.
+        */
+       private int compareVersion(String v1, String v2) {
+               String[] t1 = v1.split("\\.");
+               String[] t2 = v2.split("\\.");
+
+               for (int i = 0; i < t1.length && i < t2.length; i++) {
+                       int result = compareToken(t1[i], t2[i]);
+                       if (result != 0)
+                               return result;
+               }
+               if (t1.length > t2.length)
+                       return 1;
+               else if (t1.length < t2.length)
+                       return -1;
+               else
+                       return 0;
+       }
+
+       private int compareToken(String t1, String t2) {
+               if (t1 == null && t2 == null)
+                       return 0;
+               else if (t1 == null)
+                       return -1;
+               else if (t2 == null)
+                       return 1;
+
+               Integer i1 = null, i2 = null;
+               try {
+                       i1 = new Integer(t1);
+                       i2 = new Integer(t2);
+               } catch (NumberFormatException nfe) {
+                       // the format is not valid we silently compare as String
+                       return t1.compareTo(t2);
+               }
+               return i1.compareTo(i2);
+       }
+}
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