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https://issues.apache.org/jira/browse/WICKET-5518?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13912755#comment-13912755
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Sven Meier commented on WICKET-5518:
------------------------------------
>I still miss the idea in this improvement.
Take a look at this example:
public class Foo {
private List<Bar> bars = new ArrayList();
public void setBars(List<Bar> bars) {
this.bars.clear();
this.bars.addAll(bars);
// missing step: do something with bars
}
public List<Bar> getBars() {
// prevent modification from outside
return Collections.unmodifiableList(this.bars);
}
}
Yes, #getBars() could return a copy of the list, but I've come across this
pattern regularly.
With the proposed change it will be supported too.
> FormComponent.updateCollectionModel does not handle unmodifiableList
> ---------------------------------------------------------------------
>
> Key: WICKET-5518
> URL: https://issues.apache.org/jira/browse/WICKET-5518
> Project: Wicket
> Issue Type: Bug
> Affects Versions: 6.12.0
> Reporter: Petr Lancaric
> Assignee: Sven Meier
> Priority: Minor
> Fix For: 7.0.0
>
>
> FormComponent.updateCollectionModel should handle situation, when getter
> returns unmodifiable list.
> Proposed solution:
> formComponent.modelChanging();
> booelan isChanged;
> try {
> collection.clear();
> if (convertedInput != null)
> {
> collection.addAll(convertedInput);
> }
> isChanged = true;
> catch (Exception e)
> {
> // ignore this exception as Unmodifiable list
> does not allow change
> logger.info("An error occurred while trying to
> modify list attached to " + formComponent, e);
> }
> try
> {
> if(isChanged)
>
> formComponent.getModel().setObject(collection);
> else
> // TODO: create here collection as
> non-abstract successor of setObject declared argument
> formComponent.getModel().setObject(new
> ArrayList(convertedInput));
> isChanged = true;
> }
> catch (Exception e)
> {
> // ignore this exception because it could be
> that there
> // is not setter for this collection.
> logger.info("An error occurred while trying to
> set the new value for the property attached to " + formComponent, e);
> }
> // at least one update method should pass successfully
>
> if(isChanged)
> formComponent.modelChanged();
> else
> throw new RuntimeException("An error occurred
> while trying to modify value for the property attached to " + formComponent);
>
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