JSF convertDateTime validation error

Question

I have a problem mentioned in the topic. I have

    <h:selectOneMenu class="time" id="time" value="#{auctionBean.expDate}">
                                    <f:convertDateTime pattern="dd/MM/yyyy HH:mm:ss"/>
                                    <f:selectItem itemValue="11/11/1111 11:11:11" itemLabel="1 day" />
                                    <f:selectItem itemValue="#{auctionBean.calculateExpDate(4)}" itemLabel="4 days" />
                                    <f:selectItem itemValue="#{auctionBean.calculateExpDate(7)}" itemLabel="7 days" />
                                    <f:selectItem itemValue="#{auctionBean.calculateExpDate(14)}" itemLabel="14 days" />
</h:selectOneMenu>

The problem is i am getting Validation Error: Value is not valid message for all items but first one. The method:

public String calculateExpDate(int days) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(new Date());
    cal.add(Calendar.DATE, days);
    Format formatter = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
    System.out.println("data: " + formatter.format(cal.getTime()));
    return formatter.format(cal.getTime());
}

It returns String in good format. Output from system.out:

INFO:   data: 10/10/2013 20:40:04

Where is the problem? I have no clue at all

score 2 · Accepted Answer · answered Sep 26 '13 at 18:51

A good one!

If what you are getting is a VALIDATION error, not a CONVERSION problem, then the probable scenario is:

the list of available values is created, and the values have precision of 1 second,
user picks one of them,
but on postback the available values get recalculated, and they are all a couple of seconds later than the original ones.
so the value that your user picked is no more available on the list of possible values,
and so a validation error happens (which is what JSF does always when the value chosen is no longer on the list of select items).
you do not get it with the first item, because it's the only one that does not change with time :-).

If you move the backing bean to view scope (or session scope), or cut the precision, it should work. Or better yet - make an enum with values of NOW, IN_2_DAYS, IN_4_DAYS and so on. And calculate the real date after the enum is chosen.

I'd go ahead with the enum and calculate only after selection. — BalusC, Sep 26 '13 at 19:10

Mateusz Gaweł · Answer 2 · 2013-09-26T21:05:44.383

fdreger is right! I marked his post as an answer. Thanks:) This is my solution if you are lazy (however it might be done better I guess):

JSF:

<h:selectOneMenu class="time" id="time" value="#{auctionBean.choosenOption}">
                                <f:selectItems value="#{auctionBean.days}" var="days" itemValue="#{days}" itemLabel="#{days.label}"/>
                            </h:selectOneMenu>

fragment of my auctionBean:

public enum Days {

    IN_1_DAY("1 dzień", 1),
    IN_4_DAYS("4 dni", 4),
    IN_7_DAYS("7 dni", 7),
    IN_14_DAYS("14 dni", 14);
    private String label;
    private int days;
    private Days(String label, int days) {
        this.label = label;
        this.days = days;
    }

    public String getLabel() {
        return label;
    }

    public Date calculateExpDate() {
        Calendar cal = Calendar.getInstance();
        cal.setTime(new Date());
        cal.add(Calendar.DATE, this.days);
        return cal.getTime();
    }
}
private Days choosenOption;

public void setChoosenOption(Days choosenOption) {
    this.choosenOption = choosenOption;
    expDate = choosenOption.calculateExpDate();
}

public Days getChoosenOption() {
    return choosenOption;
}

public Days[] getDays() {
    return Days.values();
}

User chooses how many days his auction should be active and i calculate what is an expiration date. expDate is Date object which i set only once, after choosing the single enum and sumbitting the form. Pretty good solution suggested :)

You can improve it more by putting `calculateExpDate` logic in the enum itself. Then you just have to do `expDate = chosenOption.calculateExpDate()`. — BalusC, Sep 26 '13 at 20:46

JSF convertDateTime validation error

2 Answers2