code: public void bindValue(String varName, Value value) throws IllegalArgumentException, RepositoryException
     {
        checkInitialized();
        query.bindValue(session.getLocationFactory().parseJCRName(varName).getInternalName(), value);
     }
docs: Binds the given <code>value</code> to the variable named
  <code>varName</code>.
  
  @param varName name of variable in query
  @param value   value to bind
  @throws IllegalArgumentException      if <code>varName</code> is not a
  valid variable in this query.
  @throws javax.jcr.RepositoryException if an error occurs.