jsf2, richfaces4, multiple selects depending on each other, valueChangeListener not called

[Richard Osz]

I am new to Richfaces and Jsf2 in general, and I hope I am not asking a question with an obvious answer

I am trying to use four rich:select elements, each ones content depending on the value selected in the one before. The problem I am having is that this works ok for the first and second select, but the third and fourth are not updated.

Here is my form:

<h:form>
    <h:panelGrid>
        <rich:select defaultLabel="Click to select items type"
            value="#{selectBean.currentType1}"
            valueChangeListener="#{selectBean.valueChanged1}">
            <f:selectItems value="#{selectBean.firstList}" />
            <a4j:ajax event="change" render="second" execute="@this" />
        </rich:select>
        <rich:select id="second" value="#{selectBean.currentType2}"
            defaultLabel="Click to select item"
            valueChangeListener="#{selectBean.valueChanged2}">
            <f:selectItems value="#{selectBean.secondList}" />
            <a4j:ajax event="change" render="third" execute="@this" />
        </rich:select> 
        <rich:select id="third" value="#{selectBean.currentType3}"
            defaultLabel="Click to select item"
            valueChangeListener="#{selectBean.valueChanged3}">
            <f:selectItems value="#{selectBean.thirdList}" />
            <a4j:ajax event="change" render="fourth" execute="@this" />
        </rich:select>
        <rich:select id="fourth" value="#{selectBean.currentType4}"
            defaultLabel="Click to select item">
            <f:selectItems value="#{selectBean.fourthList}" />
        </rich:select>
    </h:panelGrid>
</h:form>

And here is my backing bean:

import java.util.*;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
import javax.faces.event.ValueChangeEvent;
import javax.faces.model.SelectItem;

@ManagedBean 
@RequestScoped 
public class SelectBean { 
    private static final String[] FRUITS = { "Banana", "Cranberry", 
        "Blueberry", "Orange" }; 
    private static final String[] VEGETABLES = { "Potatoes", "Broccoli", 
        "Garlic", "Carrot" }; 

    private String currentType1 = null; 
    private String currentType2 = null; 
    private String currentType3 = null; 
    private String currentType4 = null; 
    private List<SelectItem> firstList = new ArrayList<SelectItem>(); 
    private List<SelectItem> secondList = new ArrayList<SelectItem>(); 
    private List<SelectItem> thirdList = new ArrayList<SelectItem>();
    private List<SelectItem> fourthList = new ArrayList<SelectItem>();

    public SelectBean() { 
        SelectItem item = new SelectItem("fruits", "Fruits"); 
        firstList.add(item); 
        item = new SelectItem("vegetables", "Vegetables"); 
        firstList.add(item); 
    } 
    public void valueChanged1(ValueChangeEvent event) { 
        System.out.println("Entering valueChanged1");
        secondList.clear(); 
        if (null != event.getNewValue()) { 
            String[] currentItems; 
            if (((String) event.getNewValue()).equals("fruits")) { 
                currentItems = FRUITS; 
            } else { 
                currentItems = VEGETABLES; 
            } 
            for (int i = 0; i < currentItems.length; i++) { 
                SelectItem item = new SelectItem(currentItems[i], currentItems[i]); 
                secondList.add(item); 
            } 
        } 
    } 
    public void valueChanged2(ValueChangeEvent event) { 
        System.out.println("Entering valueChanged2");
        thirdList.clear(); 
        if (null != event.getNewValue()) { 
            String[] currentItems; 
            currentItems = FRUITS; 
            for (int i = 0; i < currentItems.length; i++) { 
                SelectItem item = new SelectItem(currentItems[i], currentItems[i]); 
                thirdList.add(item); 
            } 
        } 
    } 
    public void valueChanged3(ValueChangeEvent event) { 
        System.out.println("Entering valueChanged3");
        fourthList.clear(); 
        if (null != event.getNewValue()) { 
            String[] currentItems; 
            currentItems = VEGETABLES; 
            for (int i = 0; i < currentItems.length; i++) { 
                SelectItem item = new SelectItem(currentItems[i], currentItems[i]); 
                fourthList.add(item); 
            } 
        } 
    } 
    //Getters and setters
    public String getCurrentType1() {
        return currentType1;
    }
    public void setCurrentType1(String currentType1) {
        System.out.println("Setting currentType1 to "+currentType1);
        this.currentType1 = currentType1;
    }
    public String getCurrentType2() {
        return currentType2;
    }
    public void setCurrentType2(String currentType2) {
        System.out.println("Setting currentType2 to "+currentType2);
        this.currentType2 = currentType2;
    }
    public String getCurrentType3() {
        return currentType3;
    }
    public void setCurrentType3(String currentType3) {
        System.out.println("Setting currentType3 to "+currentType3);
        this.currentType3 = currentType3;
    }
    public String getCurrentType4() {
        return currentType4;
    }
    public void setCurrentType4(String currentType4) {
        System.out.println("Setting currentType4 to "+currentType4);
        this.currentType4 = currentType4;
    }
    public List<SelectItem> getFirstList() {
        return firstList;
    }
    public void setFirstList(List<SelectItem> firstList) {
        this.firstList = firstList;
    }
    public List<SelectItem> getSecondList() {
        return secondList;
    }
    public void setSecondList(List<SelectItem> secondList) {
        this.secondList = secondList;
    }
    public List<SelectItem> getThirdList() {
        return thirdList;
    }
    public void setThirdList(List<SelectItem> thirdList) {
        this.thirdList = thirdList;
    }
    public List<SelectItem> getFourthList() {
        return fourthList;
    }
    public void setFourthList(List<SelectItem> fourthList) {
        this.fourthList = fourthList;
    }
}

I can see by the debug println statements that the valueChangeListener method for the second select is not called, so the list of values for the third select is not populated.

Any thougths?

[Tim Holloway]

Welcome to the JavaRanch, Richard!

I'm not familiar with a4j:ajax. Possibly it's new to RichFaces 4, which I haven't been brave enough to attempt yet. I use a4j:support.

What works for me is that I make the valueChangeListeners do a minimal amount of work. They zap the selected value for the lower-level control (since the old value may not apply anymore), and they zap the selectItems list that goes with that lower-level control. The "getselectitems" method for the lower-level control uses a cached approach, where if the list was zapped, I rebuild it (based on the new higher-level values) and save it so that I don't repeat the process more often than strictly necessary.

One thing that you should do, however, is cascade the zapping process, since by definition invalidating a higher level invalidates all its lower levels. Don't depend on JSF to do that for you, since if you didn't change the lower-level values on the client side before submitting the form, their valuechangelisteners won't fire. The VCL controller simply compare what's in the bean to what's in the incoming data and only fire if those 2 values are different.