Figure 1 :shows how each application would be deployed to multiple servers in a production environment.  Caption Figure 1: MedRec Application Suite in a Multiple-Server Domain

It’s a Medical Transcription related project.

The MedRec application provides a framework for patients, doctors, and administrators to manage patient data using a variety of different clients.

 Patient data includes:   

• Patient profile information—A patient's name, address, social security number, and login information

• Patient medical records—Details about a patient's visit with a physician, such as the patient's vital signs and symptoms as well as the physician's diagnosis and prescriptions.

The MedRec application suite consists of two main J2EE applications and one supporting application that loads the MedRec informational page. The main applications support one or more user scenarios for MedRec:       

•  medrecEar—Patients log in to the patient Web Application (patientWebApp) to edit their profile information, or request that their profile be added to the system. Patients can also view prior medical records of visits with their physician. Administrators use the administration Web Application (adminWebApp) to approve or deny new patient profile requests. medrecEar also provides all of the controller and business logic used by the MedRec application suite, as well as the Web Service used by different clients.
• physicianEar—Physicians and nurses log in to the physician Web Application (physicianWebApp) to search and access patient profiles, create and review patient medical records, and prescribe medicine to patients. The physician application is designed to communicate using the Web Service provided in medrecEar.
• startupEar—The startupEar application is a simple Web Application that automatically starts a Web browser and loads a MedRec informational page when you start the installed MedRec domain. This application is not discussed during the development tutorials, but is compiled and deployed as part of the complete MedRec build process.

  Architecture Overview

This MedRec application is designed and implemented following the traditional three tier architecture model in which the client, server and datastore are independent from one another:

1. Presentation Tier.
2. Service Tier. 
3. Enterprise Information System (EIS) Tier. 

1.      Presentation Tier

The Presentation Tier is responsible for gathering and displaying application data, and provides the overall user experience for the MedRec application

MedRec consists of two different Web Applications: one that provides MedRec administration controls and one that provides controls for MedRec’s patient users. Web Applications are developed through Model-View-Controller (MVC) Model 2 paradigm and Struts framework.

2.      Service Tier Architecture

Service Tier is primarily made of Enterprise JavaBeans (EJBs) that work together to process requests from Web Applications, Web Services, workflow applications, and future client applications.  At the heart of the Service Tier are Stateless Session EJBs that encapsulate much of the MedRec’s business logic.  These Stateless Session Beans are referred to as Session Facades, and they process all incoming requests.  Session Facades interact with Container Managed Entity EJBs, other Stateless Session EJBs, Java Messaging Services, and helper modules in order to complete the work.

3.      Enterprise Information System Tier

The MedRec Enterprise Information System Tier is made up of a relational database management system. MedRec application data is maintained through PointBase database.

4.      Security

MedRec security takes advantage of the WebLogic Server security framework.  MedRec Administrators are managed using WebLogic Server’s default security configuration.  MedRec Patients are managed using a custom Authentication provider in conjunction with WebLogic Server’s default security configuration.  Both the MedRec Administration and Patient websites are constrained using URL pattern matching.