tailieunhanh - Lecture Software design and architecture – Chapter 13

Lecture 13 – Implicit asynchronous communication software architecture. An architecture style (also known as an “architecture pattern”) abstracts the common properties of a family of similar designs. Define a family of systems in terms of a pattern of its structural organization. | SOFTWARE DESIGN AND ARCHITECTURE LECTURE 13 Review Shared Data Software Architectures Black board Style architecture Outline Implicit Asynchronous Communication Software Architecture Implicit Asynchronous Communication Software Architecture Implicit Asynchronous Communication Software Architecture The main purpose of this type of communication architecture is to provide a decoupling between the event/message, the publishers/producers, and the subscribers/customers. These are very popular architectures in distributed applications. Implicit Invocation Style Instead of invoking a procedure directly A component can announce (or broadcast) one or more events. Other components in the system can register an interest in an event by associating a procedure with the event. When an event is announced, the broadcasting system (connector) itself invokes all of the procedures that have been registered for the event. Event-based, Implicit Invocation Style Suitable for applications that involve . | SOFTWARE DESIGN AND ARCHITECTURE LECTURE 13 Review Shared Data Software Architectures Black board Style architecture Outline Implicit Asynchronous Communication Software Architecture Implicit Asynchronous Communication Software Architecture Implicit Asynchronous Communication Software Architecture The main purpose of this type of communication architecture is to provide a decoupling between the event/message, the publishers/producers, and the subscribers/customers. These are very popular architectures in distributed applications. Implicit Invocation Style Instead of invoking a procedure directly A component can announce (or broadcast) one or more events. Other components in the system can register an interest in an event by associating a procedure with the event. When an event is announced, the broadcasting system (connector) itself invokes all of the procedures that have been registered for the event. Event-based, Implicit Invocation Style Suitable for applications that involve loosely-coupled collection of components, each of which carries out some operation and may in the process enable other operations. Particularly useful for applications that must be reconfigured “on the fly”: Changing a service provider. Enabling or disabling capabilities. Components Modules whose interfaces provide a collection of procedures/methods and a set of events that it may announce Connectors Bindings between event announcements and procedure/method calls Based on Observer pattern Basically, components communicate using a generalized Observer Design Pattern style of communication. Implicit Invocation Invariants Announcers of events do not know which components will be affected by those events. Components cannot make assumptions about the order of processing. Components cannot make assumptions about what processing will occur as a result of their events. Specializations Often connectors in an implicit invocation system include the traditional procedure call in addition to the .