Socket/XML Message Abstraction

The Core-Host API abstracts the socket handling and XML message content into a set of java classes and interfaces. Socket/channel activity is passed to the core as an event (for example, the authorise() method call). Message content is abstracted into entity classes. For example, EPSRequest/EPSCard and passed as arguments to those events. All the properties in the entity classes will have a directly related XML element or attribute, and vice versa.

The XML protocol specification should be used as the primary point of reference for how and when a particular property is used.