As a lead Software Engineer for a large organization I spend a great deal of my time designing APIs. I spend practically the same amount of time mentoring team members and evangelizing the benefits of a good design.

If you are a programmer than you are a designer; that is, you design class hierarchies and compositional relationships, determine whether an interface or abstract is needed and so forth. This is all part of designing an API, and the more thought you give to your design the better the results will be.

Conceptually, designing a quality API is pretty straight forward: all requirements must be satisfied by the design in a clean and efficient manner. However there are many details involved which you should keep in mind when designing.

Joshua Bloch, Principle Software Engineer at Google has published a very useful article which covers the various facets of good API design. If you are a programmer this is definitely worth reading. Check it out.

There are a number of different ways in which a Flex application can persist data. Typically, in most real-world situations data is persisted on the server, but for specific situations where it is logical to persist data locally on the client in order to reduce unnecessary overhead, flash.net.SharedObject is the preferred solution.

SharedObject is easy to use and provides a relatively simple base API from which developers can utilize in order to persist data locally. However, in order to enforce that local persistence is maintained consistently across applications, a more robust API is needed.

Local Persistence API allows developers to consistently work with session specific data. The data is persisted locally on the clients file-system via SharedObject. Data can be saved and accessed intuitively in accordance with rules governed by the Flash Player Security Model.

Local Persistence API provides a solution which allows developers to create session specific timestamps and genuine unique identifiers (GUID), consistently get / set and delete persisted properties without knowledge of the underlying implementation, specify specific object encoding for persisted SharedObjects as well as SharedObject name validation and invalid charachter substitution.

Local Persistence API is protected under the MIT license. You can download the LocalPersistenceAPI bundled compiled source, asdoc and uml documentation.