Grendel:Specification:Filters

There should be three types of "Filters"

Types

• Message Filters which take in Messages Lists and return Message Lists
• Message Views which take in Messages Lists and return Message Lists
• Message Actions which take in Messages Lists and return success/failure

Purpose

• Filters and Views are passive; they don't affect the underlying message.
• Actions affect the message.

• Views alter the users' view of messages, they are a transformation but they don't affect the underlying message.
• Filters change the number of messages; they select messages biased on criteria and return that list.

Interaction

The Filters and Views can be chained, and then supplied to an Action.

Spam

A Spam "Filters" is a special kind of Filter (It returns the Message List containing only Spam)

References

See: http://www.mozilla.org/projects/grendel/filters.html for a discussion on Filters