Book Image

Enterprise Application Development with Ext JS and Spring

By : Gerald Gierer
Book Image

Enterprise Application Development with Ext JS and Spring

By: Gerald Gierer

Overview of this book

Spring and Ext JS are cutting edge frameworks that allow us to build high performance web applications for modern devices, that are now consuming data at a faster rate than ever before. It is the appropriate time for you to understand how to best leverage these technologies when architecting, designing, and developing large scale web development projects. This practical guide condenses an approach to web development that was gained from real world projects, and outlines a simple, practical approach to developing high performance, and enterprise grade web applications. Starting with configuring Java, NetBeans, and MySQL to prepare your development environment, you will then learn how to connect your NetBeans IDE to the MySQL database server. We will then explore the Task Time Tracker (3T) project database structure and populate these tables with test data. Following on from this, we will examine core JPA concepts after reverse engineering the domain layer with NetBeans. Leveraging the Data Access Object design pattern, you will learn how to build the Java DAO implementation layer assisted by generics in base classes, followed by a Data Transfer Object enabled service layer to encapsulate the business logic of your 3T application. The final chapters that focus on Java explore how to implement the request handling layer using Spring annotated controllers, and deploy the 3T application to the GlassFish server. We will then configure the Ext JS 4 development environment and introduce key Ext JS 4 concepts, including MVC and practical design conventions. Covering a variety of important Ext JS 4 strategies and concepts, you will be fully-equipped to implement a variety of different user interfaces using the Ext JS MVC design pattern. Your journey ends by exploring the production build and deployment process using Maven, Sencha Cmd and GlassFish.
Table of Contents (22 chapters)
Enterprise Application Development with Ext JS and Spring
About the Author
About the Reviewers
Introducing Spring Data JPA

Chapter 6. Back to Business – The Service Layer

The service layer is the nucleus of the application; it is where the business logic resides. The business logic encapsulates the rules that define the working application and it is where a significant amount of development time is spent. Enhancements, changing requirements, and ongoing maintenance will usually require modifications to the service layer. Business rules may include such operations as restricting access to specific roles, security constraints, calculations, validations, compliance checks, and logging, to name a few.

Some typical business logic examples could include the following:

  • Only administrators can change the country assigned to a user

  • Administrators can only change a user to a country in their own geographical region

  • If payment is made in a currency other that USD, an exchange rate premium of 5 percent must be added

  • An Australian zip code must be exactly four digits

  • Reassigning an invoice to the Canadian affiliate can only be...