# Example: XML MetaData Cache Control

The following scenario describes how the XML MetaData Cache is deployed by business processes in a workflow.

The following elements are involved:

- The Router process: A business process that routes the flow of information between the Seller and the client, and the Buyer and the client.
- The Seller process: The Seller process communicates with the Router process, which in turn communicates with other elements in the workflow.
- The Buyer process: The Buyer process communicates with the Router process, which in turn communicates with other elements in the workflow.
- Auction client: The auction Website, with which both the Seller and the Buyer processes interact via the Router.

The Seller puts up goods for sale on the auction client and the buyer bids for the goods. When the bid is approved, the Seller requires the Buyer's details to proceed with the sale. Communication between the various elements of the workflow is handled by the Router process.

When the Buyer's bid is approved, the following scenario takes place:

1. The Seller sends a request to the auction client for the Buyer's metadata. This metadata can include information such as the buyer's name, address, telephone number and so on.
2. The Router examines the request and, based on the content of the request, pings the Buyer process for the required metadata.
3. The buyer's information is contained in an XML document, present in the global XML MetaData Cache. The Router sends a request to the Buyer for the relevant key.
4. The Router retrieves the key from the Buyer and uses the XML MetaData Cache Control to perform a get request for the required metadata. The retrieved XML metadata is returned to the client. In this event, the Router process adds an XML MetaData Cache Control, and uses the get (String key) method to retrieve the Buyer's XML metadata. The XML MetaData Cache Control, is in effect, added to the Router process. This allows for smooth data retrieval.

Note: To enable successful transfer of information, the Buyer's metadata has to be present in the cache, before the Router JPD is deployed.