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copied!<p>Put the bean in the view scope and get rid of any business logic in getter methods. </p> <p>The bean must be placed in the view scope so that all previous selections and new available items are remembered, otherwise things will fail if e.g. <code>rendered</code> attribute depends on a condition which was only set in a previous request, or if JSF needs to validate the selected item against list of available items.</p> <p>The getter methods should not contain any business logic as they will also be invoked during a.o. validations phase. You should use <code><f:ajax listener></code> to perform business logic based on a change. You should in the listener method also explicitly clear out selected values of child dropdowns. You can use <code><f:ajax render></code> to update the contents of child dropdowns. </p> <p>Thus, so:</p> <pre class="lang-html prettyprint-override"><code><h:selectOneMenu id="state" value="#{nodes.selectedState}"> <f:selectItem itemValue="#{null}" itemLabel="-- select --" /> <f:selectItems value="#{nodes.availableStates}" /> <f:ajax listener="#{nodes.changeState}" render="city region station" /> </h:selectOneMenu> <h:selectOneMenu id="city" value="#{nodes.selectedCity}"> <f:selectItem itemValue="#{null}" itemLabel="-- select --" /> <f:selectItems value="#{nodes.availableCities}" /> <f:ajax listener="#{nodes.changeCity}" render="region station" /> </h:selectOneMenu> <h:selectOneMenu id="region" value="#{nodes.selectedRegion}"> <f:selectItem itemValue="#{null}" itemLabel="-- select --" /> <f:selectItems value="#{nodes.availableRegions}" /> <f:ajax listener="#{nodes.changeRegion}" render="station" /> </h:selectOneMenu> <h:selectOneMenu id="station" value="#{nodes.selectedStation}"> <f:selectItem itemValue="#{null}" itemLabel="-- select --" /> <f:selectItems value="#{nodes.availableStations}" /> </h:selectOneMenu> </code></pre> <p>with</p> <pre><code>@ManagedBean @ViewScoped public class Nodes { private String selectedState; // getter+setter private String selectedCity; // getter+setter private String selectedRegion; // getter+setter private String selectedStation; // getter+setter private List<SelectItem> availableStates; // getter (no setter necessary!) private List<SelectItem> availableCities; // getter (no setter necessary!) private List<SelectItem> availableRegions; // getter (no setter necessary!) private List<SelectItem> availableStations; // getter (no setter necessary!) @EJB private SomeService someService; @PostConstruct public void init() { availableStates = someService.listStates(); } public void changeState(AjaxBehaviorEvent event) { availableCities = someService.listCities(selectedState); selectedCity = selectedRegion = selectedStation = null; availableRegions = availableStations = null; } public void changeCity(AjaxBehaviorEvent event) { availableRegions = someService.listRegions(selectedCity); selectedRegion = selectedStation = null; availableStations = null; } public void changeRegion(AjaxBehaviorEvent event) { availableStations = someService.listStations(selectedRegion); selectedStation = null; } // Generate necessary getters+setters here. You should not change them. } </code></pre> <h3>See also:</h3> <ul> <li><a href="https://stackoverflow.com/questions/7031885/how-to-choose-the-right-bean-scope">How to choose the right bean scope?</a></li> <li><a href="https://stackoverflow.com/questions/11360030/best-way-to-add-a-nothing-selected-option-to-a-selectonemenu-in-jsf/">Best way to add a "nothing selected" option to a selectOneMenu in JSF</a></li> <li><a href="https://stackoverflow.com/questions/6848970/how-to-populate-options-of-hselectonemenu-from-database">How to populate options of h:selectOneMenu from database?</a></li> <li><a href="https://stackoverflow.com/questions/11879138/when-to-use-valuechangelistener-or-fajax-listener">When to use valueChangeListener or f:ajax listener?</a></li> <li><a href="https://stackoverflow.com/questions/2090033/why-jsf-calls-getters-multiple-times/">Why JSF calls getters multiple times</a></li> </ul>

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