code: public String[] getVariables()
      {
          if (variables == null)
          {
              variables = new LinkedHashSet<String>();
              for (Expression e : getExpressions())
              {
                  for (VarSpec v : e.getVarSpecs())
                  {
                      variables.add(v.getVariableName());
                  }
              }
          }
          return variables.toArray(new String[variables.size()]);
      }
docs: Returns the list of unique variable names, from all {@link Expression}'s, in this template.
  
  @return