+ /**
+ * Returns an error message string if the search string is invalid, else
+ * returns null.
+ *
+ * Currently validation is limited to checking the string is not empty, and is
+ * a valid regular expression (simple searches for base sub-sequences will
+ * pass this test). Additional validations may be added in future if the
+ * search syntax is expanded.
+ *
+ * @param searchString
+ * @return
+ */
+ protected String getSearchValidationError(String searchString)
+ {
+ String error = null;
+ if (searchString == null || searchString.length() == 0)
+ {
+ error = MessageManager.getString("label.invalid_search");
+ }
+ try
+ {
+ Pattern.compile(searchString);
+ } catch (PatternSyntaxException e)
+ {
+ error = MessageManager.getString("error.invalid_regex") + ": "
+ + e.getDescription();
+ }
+ return error;