The ActionDefinition represents the definition and metadata for a single
action execution, which is equivalent to one execution of any given
Component.
An OutputHandler manages the content generated from a Component execution.
Output can take the form of the generated results from a component, or
content that solicits additional information from the requester.
The SequenceDefinition represents the definition of several consecutive
action definitions that comprise an ActionSequence object, which is the
runtime equivalent of an action sequence document.