+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 {
+
+ @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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