Product detail pages display a “breadcrumb” trail that reflects the navigational path to the page. For example, the following illustration shows the breadcrumb trail for a product that a customer accessed by navigating the category path Home > Home Accents > Lamps and Lighting > Desk Lamps:

Each entry in the trail is a link to the corresponding Endeca-driven category page. So, in the trail shown above, if the customer clicks Home Accents, the Home Accents category page is displayed.

If a customer accesses a product without proceeding through the catalog hierarchy, the breadcrumb trail reflects the default path to the product. There are several ways to make a navigational jump like this, such as clicking the link for a featured product or selecting a product returned by a search.

Note that the breadcrumb trail displayed on product detail pages is distinct from the dimension-selection breadcrumbs displayed on category and browse (search results) pages, which are described in the Using Cartridges chapter. The breadcrumbs that appear on product detail pages are created using the historical navigation mechanism described in the ATG Commerce Guide to Setting Up a Store.

To track a customer’s navigational path, links to products pass parameters to the /atg/commerce/catalog/CatalogNavHistoryCollector servlet bean. These parameters specify modifications to the navigational history, which is stored as a List of locations in the navHistory property of the /atg/commerce/catalog/CatalogNavHistory component.

The breadcrumb trail is rendered by the store.war/navigation/gadgets/breadcrumbs.jsp gadget. This gadget iterates over the navHistory property to get the List of ATG categories, and then uses the /atg/commerce/endeca/cache/DimensionValueCacheDroplet servlet bean to look up the URLs of the corresponding Endeca-driven pages in the dimension value cache. See the ATG-Endeca Integration Guide for information about this droplet and the cache.