Pattern-Oriented Software Architecture, A System of Patterns

Chapter 2Architectural Patterns

Layer Cake

2 cl. White Crème de Cacao2 cl. Apricot Brandy2 cl. Double cream

Pour Crème de Cacao into a Pusse-Café glass. Add the Apricot Brandy by carefully letting it flow over the back of a spoon that is touching the inside of the glass. Add the cream in the same way as the Apricot Brandy. The individual layers must not be mixed.Drink while reading the Layers pattern.

 

Architectural patterns express fundamental structural organization schemas for software systems. They provide a set of predefined subsystems, specify their responsibilities, and include rules and guidelines for organizing the relationships between them.

In this chapter we present the following eight architectural patterns: Layers, Pipes and Filters, Blackboard, Broker, Model-View-Controller, Presentation-Abstraction-Control, Microkernel, and Reflection.

2.1 Introduction

Architectural patterns represent the highest-level patterns in our pattern system. They help you to specify the fundamental structure of an application. Every development activity that follows is governed by this structure—for example, the detailed design of subsystems, the communication and collaboration between different parts of the system, and its later extension.

Each architectural pattern helps you to achieve a specific global system property, such as the adaptability of the user interface. Patterns that help to support similar properties can be grouped into categories. In this chapter we group our patterns ...