My application allows users to enter a USA address (street address, city, state, ZIP) and once all these are entered a background thread sends the address to Yahoo’s Geocoding service that returns a latitude/longitude pair to displayed in a transient attribute geoCoordinates. This service takes at least a second or two depending on latency and is therefore too costly to recalculate every time the data is reloaded from the persistent store. On page 97 of the book, under the section Expensive Calculations, it is recommended that time-consuming calculations should be persisted in Core Data but no specific example is given. Is there a particular example in the various projects provided for the book that implement this?
This is a perfect example of an expensive calculation. In this case I would have two floats in your address object for lat and long. Give them an out of bounds default value (like 1000) so you know when they have not been set.
Wonderful!!! Thank you!!!