The Research And Realization Of Middleware In TGOP Application Customization Tools

By introducing the application of database middleware in Telecom General Object Platform (TGOP), in this paper, the generation of middleware technology and its operating principle, operating conditions and practice in TGOP project are discussed. Also in this paper, the necessity and advantage of developing middleware are analyzed. The practical application of database middleware, including the basic element component of middleware, the flow or work, middleware affair dealing function, the choice of database middleware interface, the choice of design mode, the choice of developing platform etc., are emphatically discussed. Middleware is a kind of independent system software or service program. Middleware provides the service of connection between client computer and server. These service has standard program interface and protocol. According to different operating system and hardware platform, they can have various realization that comply with the criterion of interface and protocol. Middleware serves as a link between distributed client and server, many of the logic transactions are handled by middleware, in the same time, it also has functions such as affair management, load balancing and web based computing. In this project, the database middleware is designed using EJB technology. EJB is a kind of distributed model frame based on middleware developing. It includes reusable element of operation logic, allows to separate application logic and system service. In this way, the developer can focus on operation logic, and complex affairs such as distributed protocol and status management etc. are left to the server. It has the characteristic of "Once code is written, it can be reused". EJB component structure is built up by four parts of local interface (EJBHome), remote interface (EJBRemote), component interface (EJB object) and component object (Bean realization class). Local interface is responsible for the operation of controlling the lifetime of Bean: creating, deleting and searching for Bean. Remote interface will duplicate all the business logic methods exposed by corresponding Bean class, in order to clone these business method when EJB objects are created automatically. Component interface define operation methods Bean provides to clients. Component object define all the realization detail of operation logic. When an EJB component is developed, besides the four components mentioned above, it should also include deploy description file (descriptor), manifest file (Manifest), EJB-jar file. EJB has three types of Beans, session bean, entity bean and message driven bean. In system development, considering system does not need to save the conversation status with a specific client, and session bean entity can exchange freely between client computers through EJB container, a small quantity of conversation bean can thus serve large amount of client computers. So as to improve system flexibility and portability, we mainly adopt session bean to design. Before understanding the operating principle of middleware, J2EE technology, JDBC and JNDI is briefly introduced. 1. J2EE (abbreviation for Java2 Platform Enterprise Edition) is a whole set of fully functional enterprise level middleware developingcriteria. It provides component based method to design, develop, assemble and deploy enterprise level application. J2EE platform provides a multilayer structure distributed application model. This model has the ability to reuse its component, data exchange based on extensible markup language (XML), uniform security model and flexible affair control. J2EE is a criteria, its main objective is to provide a platform independent, transplantable, multi-user, secure and standard enterprise Java server side deploy platform. 2. JDBC is a Java language database interface that can be used to execute SQL sentences. It is composed of some classes and interfaces written in Java language. JDBC provides database application developers and database foreground tool developers a standard application interface, it makes developers to be able to write complete database application program using pure Java language. As Java language is independent to platform, database accessing program written in JDBCAPI has very good versatility and portability, so JDBC is adopted as database accessing interface in design. 3. JNDI is the JAVA naming and content interface in J2EE platform. J2EE application uses JNDI to search and create interface used by EJB and connect with JDBC. When client calls for database middleware, EJB middleware remote interface is found through JNDI, Bean object is found through remote interface, and then database middleware is called to realize data manipulation. In common use, The Database Accessing Interface have CGI, WEB API ,ODBC,JDBC and so on, The CGI cann't sustain data comprell access,namely CGI program cann't share by many client request, when CGI accept a client request ,Even if a CGI program is running ,also must restart a same instance, i.e to create a combine process, the more that combine request, the more which to need to create combine process, engross a great deal of memory, restrict the need memory resource of application program itself, Morever, every request create a process will consume a good many time, in multiuser application which need more Database connection ,Adopting CGI to connect Database will increase the wait time of connect database while the user increase, cause to system performance reduce, as a result , The system will breakdown. WEB API can only function on special WEB Server and operation system, which cann't replant each other; ODBC is a standard interface of database access, It sets up a set of criterions, and provides a set of standard API (Application Programming Interface) for database access, so the application program can access the data which save in various differ database manage system via ODBC API. moreover regardless every DBMS use what data sava format and programme interface .But It hasn't optimize DataSource ,can influence on database storage and reduce speed, Also only can using in relation database. As a result ,It is very difficult to access object database and other not ralation database by ODBC . The operating principle of middleware is: firstly client side searches for Home object through JNDI, one reference of the found Home object is then returned to client side, client side then uses Home object to create EJB object and returns the reference of EJB object to clientside, client side calls operation method in EJB object through remote interface, EJB object sends commitment request to Bean according to operation method called by client, Bean then complete this operation method by operating the data in database. TGOP software platform faces mainly towards telecom domain. It provides a united telecom domain network management general object platform that includes application customization, general preset, system integration and model management, it can quickly perform demonstration in telecom domain, demo actual measurement and network management project. Application customization tool in TGOP is for providing individualized application customization platform for upper level present and security management. It mainly includes customization of topological tree, table, menu and security. By customization of different element, network software individualized management is achieved. This makes the software to be more humanization, manager can design their own user interface according to requirements, so personnel with different right will see different interface, content and function.This achieves the effective management of entire system, meets the demands of complex network management, which makes the software to be more secure, flexible in management and using, makes their function to be more perfect and their layer to be more clear. TGOP adopts three-layer system structure, i.e. client layer –operation logic layer –data layer. In operation logic layer, middleware completes logic operations of database (including functionslike saving, loading, modification, business method realization, andaffair dealing), reduces the burden of client layer logic dealing, makes it to be more independent from layer to layer, and makes system maintenance and secondary development easier. The application of database middleware technology enhanced system efficiency, reduced development cycle. It is well applied in TGOP project.