Architecture
OAS adopts a popular thin customer three-layer architecture. There are three levels: HTTP layers, OAS layers and application layers. Each layer contains Multiple functional components can be distributed over multiple nodes to improve the system's scalability and robustness. Among them, the HTTP layer is managed by the listener (ie, the HTTP server, the request to process the arrival, and will request when necessary Feed the scheduler), the adapter interface (responsible for assigning the IIOP request to the type matching plug-in case) and the virtual path manager (providing plugin box type information and authentication information). With the increasing popularity of the web application and CORBA technology, Corba-based objects that replaced HTTP in IIOP have greatly improved the performance and scalability, scalability, reusability of web applications. However, HTTP / CGI-based traditional web applications still exist, completely replace The new object Web is unrealistic. OAS's HTTP layer passes the seamless integration of CORBA IIOP and HTTP / CGI, which guarantees the compatibility of traditional web applications and supports the latest object web applications, which is very good. Coordination between protecting investment and technology leaders.
Using
OAS to build an application development and management platform for building enterprise web systems, using simple and easy to learn, rich management features, superior performance, OAA application can be generally divided into plug-in box-based applications And CORBA applications.
1. Plug box Application
OAS provides a plug-in box server. It is a shared library that enables program logic access. Insert one or more plug-in box instances in the plug-in box server The plugin box provided by .oas is divided into the following:
. PL / SQL plug-in box
Run the PL / SQL stored procedure in the Oracle database to generate dynamic HTML. Using the PL / SQL plug-in box is the easiest way to accumulate data from the Oracle database.
. The JWEB plug-in JWEB plug-in box is running Java applications, which is the most convenient way to access Oracle data. There are two ways to use the JWEB plug-in box access data:
1PL2JAVA generates a Java method for the PL / SQL process stored in the database, and is called by Java;
2 use JDBC The interface executes the SQL statement. '
. LiveHTML Plug-in box Explanation SSI (Server-Side Includes) document (SSI is embedded in a static HTML document, which can group the home page into an application object, and make customer requests or even user sharing data access; < /> (> (PERL plug-in box) running the Perl script, working with various modules;
.c plug-in box Run C Application. Cap box is working together with the WRB (Web Request Broker) API;
.odbc plug-in box ODBC plug-in box allows you to access data from other databases with ODBC API.
2.corba Application
OAS allows development based on CORBA objects Applications, communication protocols support the following two application modes: CORBA applications and EJB (Enterprise JavaBeans) applications. These two modes allow different CORBA clients to access.
.jcorba app
In JCORBA mode, use components written by Java as a CORBA component, which is called JCORBA object JCO, which can be packaged as Java classes to constitute JCORBA applications running in the OAS environment. A JCORBA application contains one or Multiple JCO;
.ejb Application
EJB is a standard that Sun has developed for developers to generate custom component applications, including EJBs provided by the developer itself. Or the EJB provided by a third party. These beans provide business logic in EJB applications. EJB applications are well-flexible and can use different vendors. For example, you can use A company's installation management software, b Bean container and C company bean. In OSA, EJB application supports in the CORBA environment, that is, these beans themselves are CORBA objects and communicate with other CORBA objects. Bean container is also a Corba object, other in the application server Level interaction.
OAS manager is a tool for configuring and managing applications, providing integrated operational various system management functions and unified interfaces.
Advantages
1. Flexible application development
OAS has a rich application development solution, which supports CGI programs, plug-in applications, JCORBA applications, and EJB. At the same time, OSA provides a variety of mechanisms, which makes it easy for users to be on the web. Publish database information. Where PL / SQL plug-in box can store application logic in the form of stored procedures, can be produced with existing stored procedures, easy to generate HTML pages, and make full use of existing technologies; PL2JAVA is not Do any changes, you can use the Oracle database PL / SQL package, support PL / SQL or Java write logic; C plug-in supports developer control application logic and database access, fully supports transaction applications, access transaction services written by X / Open TX API, pass Local Oracle Interface Implementing the Optimal Performance Database Access Mechanism.
2. Complete security feature
OAS provides authentication and encryption mechanism to prevent unauthorized users from accessing application logic and state HTML pages, support security settles SSL3.0 version, providing powerful OAS-based application safety protection. OAS supports the following security system:
. Based on authentication system, summary authentication system, Oracle basic authentication system and encrypted authentication system;
. IP address and domain limit system. The institution is allowed to authorize the machine access page or application;
. Certification system. The application server connects a directory server to verify the validity of the customer certificate.
3, powerful system management
Enterprise-level Web system application has system management functions such as maintenance management, fault management, performance management, quality management, status statistics, development planning. OAS provides a rich tool and mechanism to support various system management functions, ensuring that the system is well maintenanceability and ease of use:
OAS 4.0 provides the OAS manager for the configuration and management of OAS. This tool is similar to Windows Explorer, interface-friendly and easy to use. It allows administrators to easily and efficiently maintain an OAS site via HTML form or Java navigation applet.
OAS provides component distribution mechanisms and dynamic start / stop. When the load increases, the new node can be dynamically increased to extend the processing capability and performance of the system. When the peak is peak, the node can be reduced as appropriate to ensure a good utilization rate. In a multi-node's OAS application, the OAS, listener and plug-in process can run on the primary node and remote nodes, the components' audible and dynamic start / stop system help to improve system performance, balanced load, and reduce single failure. Hazard, improve system resources will provide a strong guarantee mechanism for a variety of system management functions.
OAS provides efficient and practical fault recovery policies and mechanisms. To avoid working loads that will identify and restore all component failures in a single component, OAS uses the fault location and recovery mechanism for self-supervision. When an accident occurs, the OAS will discover the fault and restart the fault component while reloading the status information reserved by the system. The self-recognition mechanism greatly reduces the work burden of the management system fault management, the distribution of fault recovery mechanism meets the distribution of system components, and the harm of single-point faults will minimize the whole system, and strongly guarantees normal system. run.
OAS provides tools and has a built-in mechanism support site, listener, and status monitoring. Application You can use the log service API to record the information to the log file, and the OAS also supports the public log file format CLF and the expansion of the daily-eM file format XLF. The OAS Manager also provides analysis of eMu files and component status data tracking and statistics. Provide a sound underlayer mechanism for system performance management, quality management, and status statistics.
OAS allows the user to implement multiple types of load balancing by configuring the OAS manager, including node load configuration, by equilibrium distribution plug box servers to various nodes to dynamically adapt to the load, OAS support dynamic The node is in a running system to handle excessive load, OAS real-time monitoring, such as the use of system resources such as CPU, memory, exchange zone, and adjust the distribution of the plug-in box in each node, avoid system resources or borrowing insufficient borrowing. OAS ORB daemon is transferred to different customers to different customers (ie, servers), avoiding a CORBA object load overweight. The load balancing mechanism of OAs greatly improves system performance, system components availability, and strongly supports system maintenance management, quality management, performance management, and fault management.
4, rich OAS service
to call the function of the plugin box to ensure the interoperability between the internal components of the OAS; its second is the transaction service, OAS OAS provides a rich service Improve the function, performance and availability of the system. These services include the following categories: One is the plug-in information exchange service ICX, which implements the ICX protocol independent of the transport layer by imitation HTTP, supports the request / response mechanism between the plug box. When packaged in a plug-in box, other plug-in boxes can use ICX transaction services to allow application to perform distributing Venus transactions. Transaction services are responsible for start, submit, rollback transactions, and track sequences within the transaction range. Transaction Services is closely related to the database access API relationship, database access API analysis and executes SQL statements, and then obtain the results. Transaction Services uses JavaSoft defined JTS to extend the OTS model of OMG and supports OpenGroup defined JTS models. The transaction service guarantees both the distribution of the intermediate application logic and storage layer data, and greatly facilitates the design and development of application logic, providing the most direct and effective support for the transfer of application logic from database logic to the middle layer. Mechanism, ensuring the entire application system realizes the trifunct three-layer architecture; finally the content service, it provides an API for application logic storage permanent content data to ensure the flexibility of the system, which can meet the needs of different applications.
All, OA provides a comprehensive solution for enterprises to build web-based applications.