[jbossseam-issues] [JBoss JIRA] Commented: (JBSEAM-880) Make UISelectItems more permissive to null-values

[ http://jira.jboss.com/jira/browse/JBSEAM-880?page=comments#action_12353520 ] Guy Veraghtert commented on JBSEAM-880: --------------------------------------- Interesting discussion. How about following case ? (details left out) <h:selectOneMenu value="#{bean.parent}" valueChangeListener="#{...}"> <s:selectItems value="#{allParents}" noSelectionLabel="[Please select]"/> </h:selectOneMenu> <h:selectOneMenu value="#{bean.child}" disabled="#{empty bean.parent}"> <s:selectItems value="#{bean.parent.children}" noSelectionLabel="[Please select]"/> </h:selectOneMenu> You have a screen with two dropdowns, the second isn't enabled until a selection is made in the first one and allows you to choose one of the selected parent's children. With the current implementation of UISelectItems, a dummy Parent must be returned by the getParent() method on bean, not an existing one, otherwise that parent will be pre-selected in the first dropdown, which we don't want. If we don't provide this dummy parent, an exception will occur, because bean.parent evaluates to null and hence also bean.parent.children, although a parent instance getChildren() method always returns a non-null value. When adding an empty list the user woudn't see an empty dropdown, but a disabled one, with [Please Select] as the first value. So, I would opt for the alternative with the empty list and a WARN message ;-), as you could have guessed. (However, be careful that the log statement doesn't cause another exception) -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://jira.jboss.com/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira