WebObjects 5.0 Developer Documentation

Setting the Property Key

When the template begins to render the query fields for the entity's attributes and relationships (like the category and the release date) it encounters the WORepetition labeled ResourceRepetition. See Listing 3-4 and Listing 3-5. The WORepetition's list attribute is bound to d2wContext.displayPropertyKeys. Since displayPropertyKeys is not in its dictionary, the Direct to Web context resolves the key using the rule engine, which causes the following rule to fire:

*true* => displayPropertyKeys = "defaultPropertyKeysFromEntity"

The defaultPropertyKeysFromEntity key refers to a method that derives a value based on the Direct to Web context's dictionary. See "The Rule System" for more information about the how derived values are handled. The defaultPropertyKeysFromEntity method returns an NSArray containing the Movie entity's property keys, which resolves the WORepetition's list binding.

As the repetition iterates, it sets the item attribute for each of the objects in the list. The first object is the string "category". Since item is bound to d2wContext.propertyKey, the Direct to Web context sets the value for propertyKey in its dictionary to "category". At the same time, it sets the value for the attribute key to the category EOAttribute and the value for the relationship key to null, since a Movie's category property is an attribute and not a relationship. Now the Direct to Web Context dictionary contains the information listed in Table 3-7.

© 2001 Apple Computer, Inc.