Does this feel right? new Model(defaultMinimumValue()) What happens if the model object changes? How do you propagate the new value to form components?
-Matej Janne Hietamäki wrote: > This mail is originally from wicket-user, but I reply here to get > more attention. > > This looks pretty elegant way to do the thing. Any objections before > I commit this into the trunk? > > Janne > > On Sep 23, 2006, at 4:50 PM, Joni Freeman wrote: > >> Some months ago there were discussion about how to use immutable value >> objects in wicket. See: >> http://thread.gmane.org/gmane.comp.java.wicket.user/12887/focus=12887 >> >> The conclusion was that wicket does not support well such a case >> currently (http://article.gmane.org/gmane.comp.java.wicket.user/ >> 12911). >> However, I think there may be pretty easy way to solve the issue. >> Provide a FormComponent which can use associated markup file, just >> like >> a Panel: >> >> public abstract class CompoundFormComponent extends FormComponent >> { >> private boolean wasOpenCloseTag = false; >> >> public CompoundFormComponent(String id) >> { >> super(id); >> } >> >> public CompoundFormComponent(String id, IModel model) >> { >> super(id, model); >> } >> >> @Override >> public abstract void updateModel(); >> >> @Override >> protected void onComponentTag(final ComponentTag tag) >> { >> if (tag.isOpenClose()) >> { >> this.wasOpenCloseTag = true; >> >> // Convert <span wicket:id="myPanel" /> into >> // <span wicket:id="myPanel">...</span> >> tag.setType(XmlTag.OPEN); >> } >> super.onComponentTag(tag); >> } >> >> @Override >> protected void onComponentTagBody(final MarkupStream markupStream, >> final ComponentTag openTag) >> { >> // Render the associated markup >> renderAssociatedMarkup("panel", >> "Markup for a panel component has to contain part >> '<wicket:panel>'"); >> >> if (this.wasOpenCloseTag == false) >> { >> // Skip any raw markup in the body >> markupStream.skipRawMarkup(); >> } >> } >> } >> >> Note, the methods onComponentTag and onComponentTagBody are copy >> pasted >> from Panel. The method updateModel() is made abstract, this is the >> place >> where the immutable value object is created from convertedInputs of >> FormComponents. Now, the IntegerRangeField (see the original >> thread) can >> be written simply as: >> >> IntegerRangeField.java: >> >> public class IntegerRangeField extends CompoundFormComponent { >> private final TextField minimum; >> private final TextField maximum; >> >> public IntegerRangeField(Form parent, String id, >> IModel/*<IntegerRange>*/model) { >> super(id, model); >> minimum = new RequiredTextField("minimum", new >> Model(defaultMinimumValue()), Integer.class); >> maximum = new RequiredTextField("maximum", new >> Model(defaultMaximumValue()), Integer.class); >> add(minimum); >> add(maximum); >> parent.add(new Validator(this)); >> } >> >> @Override >> public void updateModel() { >> setModelObject(new IntegerRange( >> (Integer) minimum.getConvertedInput(), >> (Integer) maximum.getConvertedInput())); >> } >> >> private Integer defaultMinimumValue() { >> if (rangeValue() == null) { >> return null; >> } >> return rangeValue().getMinimum(); >> } >> >> private Integer defaultMaximumValue() { >> if (rangeValue() == null) { >> return null; >> } >> return rangeValue().getMaximum(); >> } >> >> private IntegerRange rangeValue() { >> return (IntegerRange) getModelObject(); >> } >> >> public static class Validator extends AbstractFormValidator { >> ... >> } >> } >> >> IntegerRangeField.html: >> >> <?xml version="1.0" encoding="utf-8"?> >> <wicket:panel> >> <table cellpadding="0" cellspacing="0" border="0"> >> <tr> >> <td> >> <input wicket:id="minimum" type="text" class="text numeric" >> size="8" /> >> </td> >> <td> - </td> >> <td> >> <input wicket:id="maximum" type="text" class="text numeric" >> size="8" /> >> </td> >> </tr> >> </table> >> </wicket:panel> >> >> I tried this with other immutables too, like DateRanges etc. and the >> implementation was always straight forward. The original >> implementations >> were much more complex and required deep knowledge of wicket's form >> processing. It would be great to see something like this in core since >> the abstract CompoundFormComponent contains copy pasted code from >> Panel. >> >> Joni >> >> >> >> ---------------------------------------------------------------------- >> --- >> Take Surveys. Earn Cash. Influence the Future of IT >> Join SourceForge.net's Techsay panel and you'll get the chance to >> share your >> opinions on IT & business topics through brief surveys -- and earn >> cash >> http://www.techsay.com/default.php? >> page=join.php&p=sourceforge&CID=DEVDEV >> _______________________________________________ >> Wicket-user mailing list >> Wicket-user@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/wicket-user > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys -- and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Wicket-develop mailing list > Wicket-develop@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wicket-develop > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Wicket-develop mailing list Wicket-develop@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wicket-develop
