Collectors

unsetSetContext > Semantics of Dynamic View Type Specifications > Collectors

Collectors

A collector is a representation attribute whose purpose is to allow a Server relation to be modified from a representation object. It is generally used to edit n-ary relations because unary relations can be edited through reference attributes. N-ary relations can be modified via the specific collector-related callback functions defined in the class IlsRpObject. A collector is defined by:

An attribute name.

An access path to a Server relation.

The name of a representation declared in the relation target type.

For example:

view DomainView:

subscribe Domain:

represent Tree tree:

...

Collector items=nodes->item;

subscribe Node:

represent TreeItem item:...

The tree representation that corresponds to Domain has a collector, called items, that contains objects of type TreeItem. It is associated with the relation nodes.

When a component needs to add a new item object to a tree object, the callback IlsRpObject::onAddToCollection must be invoked.

When an item is to be removed, the callback function IlsRpObject::onRmFromCollection must be called.

Unlike the other representation attributes, the value of a collector is never updated by the server. It is only used by the component to edit the Server relation. Therefore, there is no need to associate an editing function with a collector attribute.

Version 5.8