Architecture and Design Method of E-commerce Application System Software

8.4 Architecture and Design Method of E-commerce Application System Software

8.4.1 Architecture of E-commerce Application System Software

E-commerce application system is a foundation of transiting the traditional business process. It integrates multifold computer information disposals and related technologies, and mainly has the following characteristics:

(1) Standard-based. (2) Server-centered. (3) Retractable. (4) Using the existed core system.

8 E-commerce Architecture and System Design

(5) Quickly deployable and applicable. (6) Manageable. E-commerce application system adopts reusable component design structure,

representing a set of abstract components and cooperative interfaces between components. The e-commerce application system structure introduced in this section is based on the industrial standard; it provides a set of complete services for developing and deploying e-commerce application system; the Web application programming model provided by it defines Web application topology and services using component structure to design a model of Web application. The component structure is based on the technical standard independent from platforms and vendors, including standards on client, application server, network, data and the infrastructure. These standards permit clients to access related data and service in any place at any time, and make the development of application software to be write-once-and-run-anywhere, and permit plugging in and playing all kinds of components. The basic system model and software architecture of e-commerce application system is introduced in the following.

1. Basic system model

E-commerce application system software architecture provides a model for designing e-commerce solution, which is based on multi-layer distributed environment. In the environment, application logics and business services in each layer are divided into different kinds of components, and these components are communicated through network. Its basic form could be described as a “logic” three layers computation model, which means that the delamination is logical, not physical. The basic 3-layer system model includes client, Web application server and connector connected to external service. The application elements in the three logical layers are connected with each other through a set of standard protocols, servers and software connectors in industry, as shown in Fig. 8.25.

Figure 8.25 Basic system model

Introduction to E-commerce

(1) Client The basic system model, which is connected to the web application server by

Internet, supports broad client devices from widely used devices such as PDA, smart-card and mobile phone to network computer and personal computer.

(2) Web Application Server The Web application server provides a run environment for application business

logic. Application software runs in Web application server and its embedded-in JVM. These server components communicate with clients and other components through HTTP or IIOP, and use the directories and secure services provided by the network infrastructure.

(3) Connector connected to external services The connector connects new business logic in the middle layer to existent

applications and data of the enterprise; thereby the Internet is connected to the enterprise seamlessly.

The e-commerce basic system model typically exemplifies the Web-oriented network computation style, and integrates three layers application elements that are display logic, business logic and data storage. The characteristics of the basic system model are as follows:

ķ Java Supporting Web explorer Client. ĸ Clients are easy to manage, hardly need to install local software and backup

data, and easy to configure.

Ĺ Enable to quickly develop and real-time deploy the Write- Once-and-Run- Anywhere application software.

ĺ Advocating software reusability, to minimize programs, maximize productivity, and improve software quality.

Ļ Fully using the existed business application and data stored in external service system, and making good use of these systems to service customers and business partners, staff.

2. Software architecture

E-commerce application system software architecture provides a set of integrated services for developing and deploying e-commerce application systems. The architecture is composed of the following key elements, which are shown in Fig. 8.26.

Web explorer-based, makes access of application system common and application components could be sent instantly;

Network infrastructure provides service such as TCP/IP, directory security and so on, and the capability of these services could be accessed through open and standard interfaces and protocols.

Application server software provides a platform formed by HTTP servers, database and transaction processing services, e-mails, and groupware service and message service to e-commerce application system.

8 E-commerce Architecture and System Design

Figure 8.26 E-commerce application system software architecture

Application integration makes heterogeneous application systems able to communicate with each other, and access to existing data and application systems with Web.

Web application programming environment provides server-side Java program- ming environment for creating dynamic and robust e-commerce application system; E-commerce application service provides special functions for high-level application in order to make it convenient to create e-commerce solutions; System management is used to satisfy the management requirements of network computation. The elements in the system are user, application, service, infrastructure and hardware;

Development tools are used to create, assemble, deploy and manage application system.

The main elements in e-commerce application system software architecture are as following. (1) Client Client usually refers to “thin client terminal”, which means that there is little

or no application logic running on client, therefore client just needs to install a few programs. The new generation client of application should be implemented with HTML, DHTML, XML or Java Applet. The new generation of application supports broad client-side devices from popularly used PDA and Smart Card to network computer and personal computer.

(2) Network infrastructure It provides a secure, retractable and distributed network platform for the whole

architecture including service based on open standard: TCP/IP and network serviceˈsecure service, directory service file and print service, etc.

Introduction to E-commerce

(3) Application server software Application server software layer provides core function for developing and

supporting the business logic of e-commerce application system which is running on the Web application server. It includes the following services: HTTP server, e-mail and community service, database service, transaction processing service and message sending service, etc.

(4) Application integration Application integration makes heterogeneous application systems communicate

with each other inside enterprises or across enterprises. The heterogeneous application system maybe implemented with different programming languages, and maybe built on different architectures. At present, a large number of key data and application programs of enterprise are hosted in the existing system. Methods adopted by application integration include connector, application message sending service, business process integration and workflow service and components integration service.

(5) Web application programming environment Web application programming environment is based on components model

and provides programming environment for creating dynamic and robust business application in Web application server. It provides related services to encourage the separation of business logic and display logic, to make application able to tailor dynamically according to users’ interest and client-side device.

(6) E-commerce application Service This part includes components oriented to the high level application, and is

built on the basis of application server software and network infrastructure to meet functional requirements of a specified application type. It is implemented according to programming model of application framework. Such as, payment service and order management service.

(7) System management System management service provides core function for supporting end-to-end

management within each enterprise, and also provides related tools and services to support the whole management lifecycle of application system, from installation, deploying to monitoring of operation characteristics. Also system management provides an approach of collaboration management between different enterprises, including strategy management and data warehouse management.

(8) Development tool Development tool is used to create, assemble, deploy and manage application

system.

8.4.2 Design Method of Application E-commerce System

E-commerce application system mainly adopts B/S mode, which is called Web application programming pattern. The design method mainly involves Web client,

8 E-commerce Architecture and System Design

Web server and standard Internet protocols. Generally, Web application can also use external non-Web application and data. Web application programming model defines Web application topology structure and methods of using services provided by framework to design Web application model, as shown in Fig. 8.27.

Figure 8.27 Topology structure of Web application The topology of Web application is shown in the above figure (including main

elements). What is worth to note is that, Web application server and external service are in different logical layers, but they may run on the same machine. In addition, functions of Web application server may be distributed in many machines. Generally, the front end and business logical part of a Web application operate on different machines. The topology of Web application includes client, Web application server, infrastructure service and external service.

1. Client

Client uses Internet technical standards (for example, TCP/IP, HTTP, HTML and XML) and Web application server to access business logic and data. The basic functions of client are to accept and validate user’s input, and display the result returned from Web application server. The client could be client on Internet, Intranet and Extranet. One of the important rules of Web application programming model is that business logic of Web application is always running on the server, rather than client. The advantages are shown as follows:

ķ Supporting broader client devices. ĸ Web application server can integrate access to resources (for example,

database), thereby to simplify the design of application, promote scalability, and provide better protection for resources.

Ĺ Business logic running on the server side is easy to protect, update and maintain.

Introduction to E-commerce

ĺ Business logic running on the server can centrally manage the application environment of users and rebuild it on different clients.

2. Web application server

Web application server is the core of Web application topology, which provides Web application with broad services such as programming design, data access and application integration. Web application can be regarded as a series of interactions between client and Web sites. The whole interaction process begins with a page displayed on the Web browser. The user clicks a button or a hyperlink in the page to generate a request, and the request is sent to the Web application server. The Web application server disposes the request, and generates a new page, which is sent back to the client. The new page displayed on the Web browser is just the result of the request, and maybe also the beginning of the next request. So, Web application includes a set of interactions or processing steps, each of which must generate a page-formed response, which is used as the entry of the next interaction (shown as in Fig. 8.28).

Figure 8.28 Interaction model of Web application Looking deeply at the details of each interaction, it is easy to find out that

there are three sharing process requests, including business logic layer, user interface layer and interaction control layer. They are illustrated in detail as the following.

ķ Business Logic Layer. It records and processes the input of users, such as the corresponding updating to add an item of commodity data, or transferring from an account to another.

ĸ User Interface Layer. It constructs HTML pages. The constructed page, then will be sent back to the user. And this layer determines the display form and style of the result presentation.

Ĺ Interaction Control Layer. It controls the elements else except the ones mentioned above. It handles HTTP request, selects components to run in the business logic layer, and selects the corresponding components from the user

8 E-commerce Architecture and System Design

interface layer according to the running results of business logic to construct the response page.

These three layers just correspond to the classic MVC (Model/View/Controller) paradigm. This is very important, because different layers typically need different developing technology and tools. Application framework provides each layer with support of using various components, among which there is a fixed interface.

3. Infrastructure service

Besides the above programming design mechanism, application developers also need running service to support Web application. Expediently locating application components, guaranteeing their usability and access security and executing them are all the key elements to implement Web application on Internet, Intranet and Extranet environment. The infrastructure service provides the following establishments to support Web application: directory service, authentication and authorization, firewall and proxy server.