Message Abstraction Layer - Patterns of Interaction

Patterns of Interaction

An operation of a service can be decomposed to a set of messages exchanged between a service provider and consumer and form a pattern of interaction. Analysis of the services given in reference shows that there are a limited number of these patterns of interaction that can be applied to all currently identified services. Standardising a pattern of interaction, which defines the sequence of messages passed between consumer and provider, makes it possible to define a generic template for an operation of a service. The MAL defines this limited set of generic interaction patterns (templates) that must be used by services defined in the MO service framework. Each operation of a service is defined in terms of one of the MAL interaction patterns. By defining a pattern and stating that a given operation is an example of that pattern, the operation definition can focus on the specifics of that operation and rely on the standard pattern to facilitate this. For example, an operation ‘doFoo’ may be defined that is an example of a pattern called ‘SUBMIT’. This operation has two parts, the pattern of messages that are exchanged (the ‘SUBMIT’ pattern) and the meaning of those messages and what ‘doFoo’ does. By defining the pattern as a standard (‘SUBMIT’) the service specification that defines ‘doFoo’ only need define the meaning of the messages and what the operation does. The MAL defines this set of patterns.