Ok, I tried changing it to RadioChoice<MilepostModel> (code below).
However, the onSelectionChanged() method STILL gets a String argument, as
verified by the printf() output "New selection is a class
java.lang.String: End (538.200)." But following that output, an exception
is now thrown. I REALLY don't understand what's going on here. I've
studied the Javadocs for RadioChoice, but they seem awfully sketchy, and
don't shed any light on this.
Caused by: java.lang.ClassCastException: java.lang.String cannot be cast
to com.uprr.enm.web.track.mend.MilepostModel
at com.uprr.enm.web.track.mend.MendStepChooseMP$4.getIdValue(
MendStepChooseMP.java:1)
at
org.apache.wicket.markup.html.form.AbstractSingleSelectChoice.getModelValue(
AbstractSingleSelectChoice.java:166)
at org.apache.wicket.markup.html.form.FormComponent.getValue(
FormComponent.java:911)
at
org.apache.wicket.markup.html.form.RadioChoice.onComponentTagBody(
RadioChoice.java:422)
at org.apache.wicket.Component.renderComponent(Component.java:2725
)
... 198 more
==================================================================
//----------------------------------------------------------------------------------------------
private RadioChoice<MilepostModel> createTestChoice(final String id, final
TrackModel track) {
final List<MilepostModel> choices = new
ArrayList<MilepostModel>();
choices.add(new MilepostModel(track.getStartMP(), "Start"));
choices.add(new MilepostModel(track.getEndMP(), "End"));
choices.add(new MilepostModel("Other"));
final ChoiceRenderer<MilepostModel> renderer = new
ChoiceRenderer<MilepostModel>() {
private static final long serialVersionUID = 1L;
@Override public String getIdValue(final MilepostModel model,
final int index) {
final Milepost mp = model.getObject();
return mp == null ? "" : mp.toString();
}
};
final RadioChoice<MilepostModel> choice =
new RadioChoice<MilepostModel>(id, choices, renderer) {
private static final long serialVersionUID = 1L;
@Override protected void onSelectionChanged(final Object
newSelection) {
System.out.printf("New selection is a %s: %s%n",
newSelection.getClass(), newSelection);
}
@Override protected boolean
wantOnSelectionChangedNotifications() {
return true;
}
};
return choice;
}
The milepost model class:
package com.uprr.enm.web.track.mend;
import org.apache.wicket.model.IModel;
import com.uprr.eni.read.vo.mp.Milepost;
//----------------------------------------------------------------------------------------------
/**
* Data model for milepost values.
* @author Dick Adams
* @.copyright Union Pacific 2012
*/
class MilepostModel implements IModel<Milepost> {
private static final long serialVersionUID = 1L;
private final String text;
private Milepost mp;
//----------------------------------------------------------------------------------------------
/**
* Constructor.
* @param value The milepost value.
* @param text The textual description of the value. For example, if it
represents the end
* of a milepost range, the text might be {@code End}.
*/
public MilepostModel(final Milepost value, final String text) {
mp = value;
this.text = text;
}
//----------------------------------------------------------------------------------------------
/**
* Constructor with no value.
* @param text The textual description of a {@code null} value.
*/
public MilepostModel(final String text) {
this(null, text);
}
//----------------------------------------------------------------------------------------------
@Override public void detach() {
mp = null;
}
//----------------------------------------------------------------------------------------------
@Override public Milepost getObject() {
return mp;
}
//----------------------------------------------------------------------------------------------
@Override public void setObject(final Milepost object) {
mp = object;
}
//----------------------------------------------------------------------------------------------
@Override public String toString() {
return mp == null ? text : String.format("%s (%s)", text,
mp.toString());
}
//----------------------------------------------------------------------------------------------
}
From: Sven Meier <s...@meiers.net>
To: users@wicket.apache.org
Date: 04/25/2012 09:55 AM
Subject: Re: Radio Choice Weirdness
>When Wicket calls my onSelectionChanged(), the argument is the display
string, not the id value.
Your RadioChoice is working on string choices so it will hand you the
selected string.
I'd suggest to let your RadioChoice work with ints or preferably
directly on the Milepost objects:
final RadioChoice<Milepost> choice = new RadioChoice<Milepost>(...);
Sven
On 04/25/2012 03:00 PM, Richard W. Adams wrote:
> My understanding of this class must be faulty. When Wicket calls my
> onSelectionChanged(), the argument is the display string, not the id
> value. For example, I'm expecting a milepost value like "123.456", but
> instead I get "End (123.456)" (the display value). Here's the code. can
> anyone see what I'm doing wrong?
>
> private RadioChoice<String> createMilepostChoice(final String id, final
> TrackModel track) {
>
> final Milepost startMP = track.getStartMP();
> final Milepost endMP = track.getEndMP ();
> final List<String> choices = Arrays.asList(new
> String[]{format(START, startMP), format(END, endMP), OTHER});
> final ChoiceRenderer<String> renderer = new
> ChoiceRenderer<String>() {
> private static final long serialVersionUID = 1L;
> @Override public Object getDisplayValue(final String model) {
> return model;
> }
> @Override public String getIdValue(final String model, final
int
> index) {
> String value;
> switch (index) {
> case 0:
> value = startMP.toString();
> break;
> case 1 :
> value = endMP.toString();
> break;
> default :
> value = "";
> }
> return value;
> }
> };
> final RadioChoice<String> choice = new RadioChoice<String>(id,
> choices, renderer) {
> private static final long serialVersionUID = 1L;
> @Override protected void onSelectionChanged(final
Object
> new selection) {
> final String selection = (String)newSelection;
> if (track == primaryTrack) {
> primaryMpChoice = selection;
> } else {
> secondaryMpChoice = selection;
> }
> }
> @Override protected boolean
> wantOnSelectionChangedNotifications() {
> return true;
> }
> };
> return choice;
> }
>
>
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