In OOP, the focus is on creating objects that contain both state and behavior. On the contrary, SOA is built on top of OOP, and allows you to create reusable services. While OOP focuses on what an application comprises, SOA focuses on the functionality of the application. ROA is based on the concept of resources. While a service represents execution of a requested operation, a resource represents the data access mechanism for a particular instance of a given data type. A resource is a distributed component that is handled through a standard, common interface. Resources are addressable using URIs.

This chapter presented a description of the fundamental concepts related to ROA, web services, and SOA. It presented an introduction to ROA and how it differs from other contemporary architectural styles, such as OOP and SOA. We discussed how the three architectural paradigms differ, and also the concepts of ROA.

In the next chapter, we will put all these concepts into practice, discuss the concepts and characteristics of RESTful web services, and explore how we can design and implement RESTful services by using WCF.