Introduction to RIA (Rich Internet application)

In my own understanding, RIA (Rich Internet application, Rich Internet Application System) is a fully powerful user-side browser, this browser can be IE (XAML), Mozilla FireFox (XUL) , Flash (Flex) and so on, at the end, that is, an upgrade of HTML, and ASP, JSP generated HTML for the client browsing, you may also need a variety of tools to generate static or dynamic of these browsers can use the script. In any case, this is an urgent and necessary trend.

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The following article is from Oracle's magazine Author: Cameron O ' Rourke

1. What is the use of Ria.

RIA (Rich Internet application, wealthy Internet applications) technology allows us to deploy rich-client programs on the Internet in a way that is as simple as using the Web. This is a user interface that is more robust, responsive, and visually interesting than the interfaces that are implemented with HTML. Whether or not the RIA will be able to replace the HTML application system as one might have guessed, RIA does offer a cheap choice for organizations that run complex applications using FAT client technology.

2. Why use Ria.

The popularity of html-based applications is due to the low cost of deployment, the simplicity of the architecture, and the ease with which HTML is easy to learn and use. Many users and developers are willing to give up the user interface improvements created by desktop computers to enable quick access to new data and application systems. The benefits of a web-based approach are much greater than the loss of some important UI features.

However, some application systems are not entirely suitable for using HTML technology. Complex application systems may require multiple fetches of web pages to complete a transaction, and in some areas, such as pharmaceuticals and finance, this often leads to an unacceptably low rate of interaction. Let me consider a project management system: we can implement it as an HTML application, but if users can see and manipulate charts, schedules, and various hierarchies, they will obviously work better.

In addition, although HTML is starting to go simple, even simple interaction activities still need to be done with a lot of scripts. Even if an input form is carefully laid out and fully scripted, it can send only a simple "name/value" pair from the browser. It would be much better if an HTML form could send and receive more complex data structures in an XML document.

Ria leverages a relatively robust client-side description engine, which delivers content-intensive, responsive, and graphically rich user interfaces. In addition to providing an interface with various controls (sliders, date Selectors, windows, tabs, fine-tuning controllers, rulers, and so on), RIA generally allows you to build graphics at any time using SVG (Scalable vector Graphics, scalable vector maps) or other techniques. Some RIA technologies can even provide full activity animations to respond to changes in the data.

Another benefit of RIA is that the data can be cached on the client, enabling a user interface that is faster than the html-based response and has fewer data to and from the server. For wireless devices and devices that need to be occasionally connected, the future trend must be towards rich clients and will gradually move away from text-based Web clients. Applications that run on laptops can be designed to work offline, or at least work offline when the connection is lost.

Figure 1 shows a typical RIA architecture. XML is often used as a format for data transfer and is sometimes used to describe the layout of a form. In many instances, the client can maintain a connection to the data source so that the server can update the client data in real time. Access to an Oracle data can be done through a Web service invocation.

Figure 1: A typical RIA architecture

3. technology for rich clients

Java :

Some fairly complex client applications (Eclipse) are written in Java, which shows that Java can be used to build almost any rich client application imaginable. So far, Java has been there for several years and fully supports the creation of a form-based user interface. In addition to the user interface components in the Java base class (jfc/swing), developers can also use the SWT Toolbox from Eclipse Project and many third-party toolkits. For graphics, you can use the Java 2D api--a very complete and very complex graphics API. Java also has the ability to support unmatched XML and Web services. You can use Java plug-in software in a Web browser or use the newer Java WEB start technology in the Java Runtime environment to deploy your application. The main flaw in using Java to build rich-client programs is its complexity (even simple forms and graphics require very cumbersome code). Its advantages are the full support of Java to Web standards, and the profound connotation of the language and class library.

XUL :

XUL (read "Zool") is an xml-based user interface language that comes from Mozilla's Open-source projects. It can be used to build form applications that not only run on Mozilla browsers, but can also run on other description engines such as Zulu (a Flash MX component) and Thinleys (a Java implementation). The XUL description engine is very small (below 100K), and it can use XML data or generate XML data. As in the case of Java, XUL also has a very large user community, which has a large number of open source tools, such as Theodore thinleteditor--, a Java application that enables you to graphically layout the user interface and generate the appropriate XUL. One of the main drawbacks of XUL is that it has not yet been supported by a major business entity. The biggest advantage of XUL is its integration with the Gecko engine (which opens the door to a large number of web standards) and is a very expressive and concise language compared to most other XML user interface description languages.

Macromedia Flash and Flex :

Flash is a well-established commercial product that introduces an interactive graphical interface to Web pages. After a recent upgrade, the new version includes the ability to build a form-style application. Although Flash is controversial (depending on the Flash Player version chosen) as the most widely deployed front-end technology on the web, more than 98% of desktop systems are said to support Falsh. Because the flash tool used to create animated graphics is powerful and visual (in contrast to other technical requirements for low-level graphics coding), graphic designers are very handy to use. The scripting language used by Flah is a variant of the Actionscript--ecmascript 1.5, which is also called JavaScript. The flex product adds an XML description language to flash that allows you to compile the user interface and be able to use Flash Player to describe it at any time. Flex enables traditional development organizations to better understand and use Flash. The biggest drawback of flex and Flash is that there is limited support for standards such as XML and Web services, and that the environment as an application development tool is not yet mature. The advantage of flex and Flash is that it can be easily used to create complex animated displays and to use Third-party attachments.

Oracle Forms :

Oracle forms is a sophisticated commercialized product for building a database-centric Internet application system. With Oracle forms, you can create a form by using a visual designer that outputs a form module file. To facilitate further processing outside the design tool, the module file is either proprietary FMT format or XML format. These module files drive a Java Run-time environment that describes the form. In addition to the standard widget for all forms, you can achieve more functionality by integrating additional pluggable Java components and some custom JavaBean. The scripting language used in Oracle forms is the same scripting language for pl/sql,oracle databases. A very interesting feature of Oracle forms is that Java api--developers who build, edit, and compile form module files can create scripts to generate numerous form applications or make global changes. The main disadvantage of Oracle forms is that Web deployments require permission to use the Oracle Application server. The advantage is that it can be tightly integrated with Oracle databases and other parts of the Oracle platform, such as single Sign-On and Enterprise Manager (Enterprise Manager), with broad support for internationalization, And the very high efficiency of creating data-centric applications.