EJB - Printable Version +- Free Academic Seminars And Projects Reports (https://easyreport.in) +-- Forum: Seminars Topics And Discussions (https://easyreport.in/forumdisplay.php?fid=30) +--- Forum: Engineering Seminars Topics (https://easyreport.in/forumdisplay.php?fid=7) +---- Forum: Computer Science Seminar Topics (https://easyreport.in/forumdisplay.php?fid=12) +---- Thread: EJB (/showthread.php?tid=55778) |
EJB - ishida - 10-04-2017 [attachment=7618] [attachment=7619] EJB Enterprise JavaBeans EJB are write once, run any where, middle tier components Logical Architecture A EJB system is logically a three-tier system. The three tiers are 1. client 2. EJB server 3. Database EJB s Role EJB specifies an execution environment Container provides services in EJB Container does not allow to access bean directly from client EJB Exists in the Middle tier Business rules (Methods) EJB Supports transaction processing Container start a new transaction when the bean is invokes Bean be allowed to manage its own transaction EJB s Role 4. EJB can maintain states Container keep track of state information You can build states less EJB 5. EJB is Simple Transaction processing Persistent storage of state Platform independent Multitier architecture Write once run anywhere EJB Logical Architecture A EJB system is logically a three-tier system The three tiers are as follows: a) The Client b) The EJB Server c) The Database (or other persistent store) Logical - because - these tiers may be single machines. Cont EJB s role in each of these tiers are: a) Client side makes call to remote EJBs. The client needs to know how to find the EJB server and how to interact. b) The EJB components live in the middle tier. The EJB objects reside inside an EJB container, which in turn resides in an EJB server. c) EJB can access the database themselves, typically via Java Database connecting (JDBC). EJB s Software Architecture The diagram presents a high-level view of the EJB architecture, showing the various relationships between the various components. Key Features of the EJB Architecture EJB bean exists within the container The bean and the client not directly access the server all access is performed against the container. Rather it talks to the bean through its home interface and its remote interface, both of which are provided by the container. EJB server handle requests for the container, and feed the container incoming client requests. |