Professional Cairngorm™

9.2. What Do They Look Like?

The interfaces associated with value objects are contained in the com.adobe.cairngorm.vo package. The following interfaces are contained in this package:

• IValueObject: The IValueObject interface is a marker interface that improves the readability of code by identifying the classes within a Cairngorm application that are to be used as value objects for passing data between tiers of an application.

• ValueObject: Deprecated as of Cairngorm 2.1 and replaced by com.adobe.cairngorm.vo.IValueObject.

The code for the IValueObject interface is as follows:

package com.adobe.cairngorm.vo
{
   public interface IValueObject
   {
   }
}

Much like the IModelLocator interface, the IValueObject interface exists simply to mark a class as a value object. Again, since the interface does not define any methods, it is not always implemented in practice.

Value objects consist of collections of related public properties. A simple value object might look as follows:

package valueObjects
{
    [Bindable]
    public class UserVO
    {
        public var firstName:String;
        public var lastName:String;
        public function UserVO()
        {
        }
    }
}

An example of a value object that uses the RemoteClass metadata tag can be seen in the ProductVO of the Cairngorm store application:

package com.adobe.cairngorm.samples.store.vo { import com.adobe.cairngorm.vo.IValueObject; import com.adobe.cairngorm.samples.store.util.Comparable; [RemoteClass(alias="com.adobe.cairngorm.samples.store.vo.ProductVO")] public class ProductVO implements ...