Background

2.1.1. XML-based Mobile Application Development Kit

This is the target toolkit we want to embed into the famous integrated development environment. This toolkit is developed by shen[1]. The objective of this toolkit is based on the concept “Write Once, Run Anywhere”. This concept is similar with Java. The toolkit translates the program to the target language assigned by users to achieve the objective “Write Once, Run Anywhere”.

This toolkit is capable of translating a program written in the extra language to that of a certain mobile environment. The language is in the abstract level, and the method to describe the application is to record all the information about this application in the document written in XML[3] language. The document described the mobile application can be translate to the program executed in many kinds of mobile execution environment. The environment for example: WML / WMLScript[4], J2ME MIDP[5]…and so on.

Figure 2-1 the structure of XML-based Mobile Application Development Kit

From Figure 2-1 the structure of the toolkit, we can find out that the description of the mobile application are divided into two parts: One is the part of the User Interface, and the other is the logic computing of the application. In the abstract level, the author design description languages based on XML. The description language for User Interface is named as PUML (Pervasive User-interface Markup Language), and the language for logic computing is named as PGML (Pervasive loGic Markup Language)

The author uses the mechanism of the XSLT[6] as the translation technology.

Using the XSLT translation mechanism, the toolkit can translate the document in the abstract level to each kind of program in physical language, and the translated program can be executed in it mobile environment.

2.1.2. Visual Studio .NET

Visual Studio .NET 2003 Professional[7] enables user to rapidly build a broad range of applications for Microsoft Windows®, the Web, and devices. With intuitive visual designers, high-performance data access tools, server-side visual designers,

native support for the Microsoft .NET Compact Framework, and inherent support for XML Web services, Visual Studio .NET 2003 Professional delivers improved reliability, security, and performance.

Visual Studio .NET 2003 enables user to address today's most pressing application development and deployment challenges, streamline business processes, and realize new business opportunities. The unified Visual Studio .NET 2003 integrated development environment (IDE) and a choice of programming languages—including Microsoft Visual Basic® .NET 2003, Microsoft Visual C++® .NET 2003, Microsoft Visual C#® .NET 2003, and Microsoft Visual J#™ .NET 2003—enable user to build applications using your existing skills. Figure 2-2 is the develop environment of Visual Studio .NET.

Figure 2-2 the develop environment of Visual Studio .NET

MExE (Mobile Execution Environment)

MExE[8][9] is the execution environment focused on the mobile devices. MExE

is published by 3GPP. They claim that there are five types of mobile devices in MExE. If any mobile device belongs to the five types, this mobile device can be the MExE device too.

The objective of MExE is to set a standard in the mobile execution environment.

This standard can be applied to the development of mobile application or the software service, makes them more convenience and fast.

According to execution environment and computing capability of every mobile device, MExE divides the execution environment into five class marks. The five calssmarks are listed as follow:

1. classmark 1 – WAP execution environment:

The mobile device in this execution environment has a lightweight browser. The browser can browse or execute the web pages written in WML/WMLScript. The device must follow the WAP standard, and is compatible with the wireless network environment.

2. classmark 2 – Personal Java execution environment:

In this execution environment, the computing power and the hardware capability of the devices are better. This execution environment (is the Java Virtual Machine) can execute the mobile application written in Personal Java (PJava), it can supports more complex User Interface of the application and the APIs.

3. classmark 3 – J2ME/CLDC execution environment

Devices in this execution environment are limited to the computing power and the hardware capability itself. Devices can not display the complex User Interface, and the screen of these devices have are usually smaller. So, the APIs

in J2ME is designed for this kind of mobile devices. The application be executed in this environment is written in the language-J2ME.

4. classmark 4 – CLI compact execution environment

The application written in the programming language (embedded C++ for example) of Microsoft can be executed in this environment.

5. classmark 5 – Virtual Palmtop network execution environment

The environment of this part uses the client-server architecture to execute the application. The mobile device only display the User Interface, and the data inputted by the user will be transmitted to the remote server for logic computing through Internet. The result will be transmitted to the mobile device back, and displayed on the screen with the suitable User Interface.

XML (Extensible Markup Language)

XML is an open meta-language, and it is text-based language. The structure and the metadata of XML are based on the tags. Because it is text-based language, people who read the document written in XML can easily read and understand it. In addition, XML provide the ability of describing data, the structure data can be read by machines.

Because XML is a meta-language, it can be used to create the other language and generate a lot of application. There are lots of applications of XML now. For example, XSLT, MateML, XPath, SOAP, and WML….and so on.