protected void initExpressionManager() {
if (expressionManager==null) {
expressionManager = new ExpressionManager(beans);
// add function mapper for command context (eg currentUser(), currentUserGroups())
expressionManager.addFunctionMapper(new CommandContextFunctionMapper());
// add function mapper for date time (eg now(), dateTime())
expressionManager.addFunctionMapper(new DateTimeFunctionMapper());
}
}