3 Replies Latest reply on Apr 15, 2009 7:56 AM by Ilya Shaikovsky

    List not updating in a datatable

    Waqas Arshad Novice

      I have a datatable in which i have multiple rows. I have two lists and one label. My scenerio is that when one list changes, it updates the second corresponding list of the same row. My code is:

      <h:dataTable id="reg_table" value="#{Test.detailList}" var="reg" >
      
       <f:facet name="header">
       <h:outputText value="TEST" />
       </f:facet>
       <h:column >
       <f:facet name="header" >
       <h:outputText value="Name" />
       </f:facet>
       <h:outputText value="#{reg.name}" />
       </h:column>
       <h:column >
       <f:facet name="header" >
       <h:outputText value="Country" />
       </f:facet>
       <h:selectOneMenu value="#{reg.country}">
       <f:selectItems value = "#{reg.country_list}"/>
       <a4j:support event="onchange" reRender="city_combo"
       action="#{Test.updateList}"/>
       </h:selectOneMenu>
       </h:column>
       <h:column>
       <f:facet name="header" >
       <h:outputText value="City" />
       </f:facet>
       <h:selectOneMenu id="city_combo" value="#{reg.city}">
       <f:selectItems value = "#{reg.city_list}"/>
       </h:selectOneMenu>
       </h:column>
      
       </h:dataTable>
      


      public class Bean {
       private String name;
      
       private List<SelectItem> country_list = new ArrayList<SelectItem>();
       private List<SelectItem> city_list = new ArrayList<SelectItem>();
      
       private String country;
       private String city;
      ..setter and getters
      }
      


      public class Test {
      
       private List<Bean> detailList;
      
       public Test() {
       this.populate();
       }
      ...setter getter
       public void populate() {
       List<SelectItem> country_temp = new ArrayList<SelectItem>();
       List<SelectItem> city_temp = new ArrayList<SelectItem>();
       city_temp.add(new SelectItem("AA"));
       country_temp.add(new SelectItem("UK"));
       country_temp.add(new SelectItem("Belgium"));
       detailList = new ArrayList<Bean>();
       detailList.add(new Bean("Abc",country_temp,city_temp, "",""));
       detailList.add(new Bean("Xyz",country_temp,city_temp, "", ""));
       }//end populate
      
       public void updateList() {
       System.out.println("Updating....");
       List<SelectItem> city_temp1 = new ArrayList<SelectItem>();
       Bean obj;
       for(int i=0; i<detailList.size(); i++) {
       obj=(Bean) detailList.get(i);
       if(obj.getCountry().equals("Belgium")) {
       city_temp1.add(new SelectItem("Brussels"));
       }
       if(obj.getCountry().equals("UK")) {
       city_temp1.add(new SelectItem("London"));
       }
       obj.setCity_list(city_temp1);
       }//end for
       }//end updateList()
      


      Now when i change the country list i get the exception:

      \
      javax.servlet.ServletException: Expected a child component type of UISelectItem/UISelectItems for component type javax.faces.SelectOne(city_combo). Found null.
       at javax.faces.webapp.FacesServlet.service(FacesServlet.java:277)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178)
       at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
       at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:390)
       at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:517)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
       at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
       at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
       at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
       at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
       at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
       at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
       at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
       at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
       at java.lang.Thread.run(Thread.java:595)
      Caused by: java.lang.IllegalArgumentException: Expected a child component type of UISelectItem/UISelectItems for component type javax.faces.SelectOne(city_combo). Found null.
       at com.sun.faces.renderkit.RenderKitUtils.getSelectItems(RenderKitUtils.java:326)
       at com.sun.faces.renderkit.html_basic.MenuRenderer.renderSelect(MenuRenderer.java:814)
       at com.sun.faces.renderkit.html_basic.MenuRenderer.encodeEnd(MenuRenderer.java:280)
       at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:861)
       at org.ajax4jsf.renderkit.RendererBase.renderChild(RendererBase.java:286)
       at org.ajax4jsf.renderkit.AjaxChildrenRenderer.encodeAjaxComponent(AjaxChildrenRenderer.java:124)
      


      Where am i doing it wrong? and is my technique ok?