A key aspect of the ATG-Endeca integration involves treating product categories both as category items in the ATG product catalog repository and as Endeca dimension values. In some contexts categories are accessed via their category IDs, while in other contexts they are accessed via their dimension value IDs.

To manage the relationship between categories and dimension values, the ATG-Endeca integration maintains a cache that maps each ATG category ID to the equivalent Endeca product.category dimension value ID. The cache supports two-way lookup, so either value can be obtained if the other one is known. Commerce Reference Store makes extensive use of this cache in both directions. For example, to create a link from an ATG-driven page to an Endeca-driven category page, it can use the cache to obtain the dimension value ID from the category ID; to provide the current category context to an ATG scenario running in a cartridge on a category page, it can use the cache to find the category ID associated with the current category dimension value.

If your Endeca environment includes multiple MDEX engines (for example, if you use a separate MDEX for each language), a separate dimension value cache is maintained for each MDEX. This avoids any collisions that might be caused by multiple MDEX engines using the same dimension value IDs.