Part 2. Using Tuscany

Part 1 gave you a high-level view of most of the features of Apache Tuscany’s SCA Java runtime. With the foundations laid, part 2 gives more detail about creating SCA components to support the various parts of your enterprise application.

Part 2 starts with chapter 4, “Service interaction patterns,” which provides an overview of the different interaction patterns used to send messages from one SCA component to another and back again. You’ll learn how the interacting components can run within the same JVM or in separate JVMs and how different styles of message exchange are configured. With SCA you can, depending on your requirements, choose whether components exchange messages synchronously or asynchronously, whether one message gives rise to a callback message, and whether a sequence of messages is grouped together in a conversation.

In chapters 5 and 6, “Implementing components using the Java language,” and “Implementing components using other technologies,” you’ll be introduced to some of the technologies that can be used to implement components when using Apache Tuscany. Chapter 5 concentrates on Java and demonstrates how SCA components can be implemented using your existing Java skills. The lightweight SCA Java annotations and API are described, giving you access to a more comprehensive set of SCA features and interaction patterns. Chapter 6 explains how the SCA programming model is presented in BPEL, Spring, and Java-based scripting languages.

In order for components to interact with other components or with non-SCA applications, communication protocols must be defined in the form of SCA bindings. Chapter 7, “Connecting components using bindings,” describes a number of different bindings including Web Services, CORBA, RMI, JMS, and EJB, covering common communication protocols.

The frontend user interface will be an integral part of your service-based application. In chapter 8, “Web clients and Web 2.0,” you’ll learn about the implementation and binding types that Tuscany supports for integrating web-based applications with SCA services. This includes servlets, JSPs, Ajax, Static HTML, Atom, and RSS.

The data that flows between components can be presented in various formats. The Apache Tuscany runtime has a flexible and extensible framework for transforming data from one format to another. Chapter 9, “Data representation and transformation,” describes this framework, giving examples of Java component implementations that use JAXB and SDO.

Chapter 10, “Defining and applying policy,” describes how the SCA policy framework allows you to control quality of service features by applying policy to your composite application. You’ll learn how, by using policy, you can control infrastructure features without requiring specific logic in your component implementations.