Introduction into component programming based on Java beans Dušan Tošić

Content 1. Introduction 2. CP paradigm? 3. Basic features of CP 4. JavaBeans and NetBeans IDE 5. Characteristics of JavaBeans programming 6. More characteristics 7. Enterprise JavaBeans (EJB) 8. Conclusion

1. Introduction Component based programming is introduced around ActiveX or Visual Basic Extensions (VBXs), and later OLE Control Extensions (OCXs) were the base of component programming. Component programming (CP) served in hiding the complexity of the Windows operating system from the programmers. JavaBeans were (on the beginning) Java's version of ActiveX/VBXs/OCXs.

2. CP paradigm? The idea to build program from more complex components was acceptable for a lot of programmers (more programming could be done using drag–and-drop components). A new category of development products (known as Rapid Application Development (RAD) tools) is created. The component programming is well-supported from UML.

Some of authors promote CP as special programming paradigm. However, some of authors recognize CP only as sub-paradigm of object oriented paradigm. Independently of that, should we teach CP anyway? Should we have separate course related to CP (obligatory or elective) or not?

3. Basic features of CP According to Juval Löwy (Programming.NET Components, O’ Relly, 2005.) some important features of CP are: Separation of interface and implementation Binary compatibility Language independence Location transparency Concurrency management Version control Component-based security

4. JavaBeans and NetBeans IDE The JavaBean specification is an example of a component standard. The JavaBeans are originally thought of as visual components, but now they are much more. A bean should be a reusable, active software component that can be manipulated into some IDE. It conforms to certain design patterns. Demonstration about using of components.

5. Characteristics of JavaBeans programming JavaBens: hide some complexity so that more junior programmers can create applications; package business domain–specific information so that nonprogrammers can build simple applications; promote software reuse; integrate with Rapid Development Environments; Provide creations with specific code from programmers who understand certain specialties that others who lack their expertise can use.

6. More characteristics The knowledge Java programming language and basic principles of object oriented programming is necessary. RAD products still require of hand coding. It is possible to speed up the development of some category of application, but not any kind of application. (For example, attempts to use JavaBeans programming for game development, communications, … have met with mixed results).

7. Enterprise JavaBeans (EJB) EJB: is a standard (technology) with well-specified: types, life cycles, restrictions, roles, and responsibilities. provides portability (if guidelines are followed carefully) allows developer to take the finished Web- application and easily deploy it on another server provides to achieve scalability in development of applications.

8. Conclusion Component programming (CP): can significantly speed up development of some kind of application is interesting for young people (junior programmers) should be included (in some way) in education of programmers (software engineers)

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