A Processing Configuration is an object that contains values for a Processing object's non-execution variables, that is all the variable structural attributes that can only be changed when the Processing object is not in the Running state. The Configuration is used for setting the initial state of the processing object. It may contain attributes related to any structural characteristic like the algorithms or strategy to be selected and values for structural parameters , such as the expected size of the incoming data, that will be used to also initialize the algorithms or internal tables that may be used for convenience. A Configuration though may also have initial values for non-structural attributes such as the controls (see paragraph on ``Data and Control Flow'').
Processing Configuration classes are in fact very much related to Processing Data classes and need to offer the same mechanisms and services. We will review them in section 4.1.2.
It is important to keep in mind that the configuration mechanism cannot be used to change parameters of a Processing object on execution state, only during an initial configuration stage. If the class needs to offer an interface for changing parameters or values on run-time the Control mechanism must be used.
Configuration related data is known as parameter arguments in Ptolemy, in order to make a clear distinction between such data and that related to data and control flow, which is known as stream arguments (see 2.2).