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Multi-tier architectures and application servers. Three-layer architecture. An application is divided into 3 main layers User interface Model Including business rules Data. Three-tier architecture. Client-server architecture The 3 main layers are kept on separate platforms
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Multi-tier architectures and application servers Multitier architectures and application servers
Three-layer architecture • An application is divided into 3 main layers • User interface • Model • Including business rules • Data Multitier architectures and application servers
Three-tier architecture • Client-server architecture • The 3 main layers are kept on separate platforms • Access is through the client-server paradigm • Change in platform affects only the layer running on that particular platform • Change of platform could be • Operating system • Windowing system • Database management system (DBMS) Multitier architectures and application servers
Three-tier architecture vs. MVC architecture • Model-View-Controller (MVC) architecture • All 3 “layers” can communicate directly • Three-tier architecture • User interface and data tiers does not communicate directly • Only through the ‘”model” tier • MVC is mainly used in single-platform applications • Though it can be used in web applications Multitier architectures and application servers
N-tier architecture • An application may involve more than 3 tiers • Example • User interface • Web server (middle ware) • Web service enabled model • Data Multitier architectures and application servers
Application server • An application server runs the “model” layer • Provides service to the user interface layer • Requires service form the data layer • Application servers can do • Persistency • Accessing the database automatically • Transaction management • Using a single or multiple databases • Web services • HTTP Multitier architectures and application servers
Java application servers • Java EE (Java Enterprise Edition) applications run on application servers • Sometimes called Java EE servers • Some popular Java EE servers • IBM WebSphere • BEA WebLogic • Oracle OC4j • JBoss • Sun GlassFish Multitier architectures and application servers
Java EE server features • HTTP • Runs Java Servlets and JSP (Java Server Pages) • Web services • Enterprise Java Beans (EJB) • Using container managed or bean managed persistency • Transaction management Multitier architectures and application servers
Java EE servers and containers Multitier architectures and application servers
Java EE 5 Platform API Multitier architectures and application servers
References • Multitier architecture • http://en.wikipedia.org/wiki/3-tier • Application server • http://en.wikipedia.org/wiki/Application_server • The Java EE 5 Tutorial • http://java.sun.com/javaee/5/docs/tutorial/doc/ Multitier architectures and application servers