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(since 1.16)

The framework allows an action to be associated with other properties or
collections of the same domain object. For complete reference see the
https://causeway.apache.org/guides/rgant/rgant.html#_rgant-Action_associateWith[Apache
Causeway Reference Guide]

We setup a simple `FibonacciNumberVm` class to demonstrate this.

[source,java]
----
@DomainObject
public class DemoItem {

    public String title() {
        return String.format("DemoItem '%s'", getName());
    }

    @Property
    @Getter @Setter private String name;

}
----

Now following demo view model holds `items` a collection of element type
`FibonacciNumberVm`. The action method `doSomethingWithItems(...)` can be thought
of as associated with the `items` collection, because it expresses this
association using the annotation `@Action(associateWith="items")`.

[source,java]
----
@DomainObject(nature=Nature.VIEW_MODEL)
public class AssociatedActionDemo extends DemoStub {

    @Inject MessageService messageService;

    @Getter private final Set<DemoItem> items;

    @Action(associateWith="items")
    public AssociatedActionDemo doSomethingWithItems(Set<DemoItem> items) {
        if(items!=null) {
            items.forEach(item->messageService.informUser(item.getName()));
        }
        return this;
    }

}
----

See the associated action demo
link:${SOURCES_DEMO}/demoapp/dom/actions/assoc[sources].
