Developer's-Panther WebSphere

Chapter 1. Overview

Panther for IBM WebSphere adds the following capabilities to Panther:

Building Enterprise JavaBeans (EJBs) in the Panther editor
Building client screens that call EJBs
Deploying Panther-built EJBs on IBM's WebSphere Application Server

Panther makes it easy to create EJBs by producing the necessary files and interfaces from your method and property definitions. Panther for IBM WebSphere works with IBM's WebSphere product family to use your EJBs in both web and GUI environments. The products work together to fulfill your e-business requirements—building your transactional database applications quickly and deploying them in a secure enterprise environment.

What is an Enterprise JavaBean Application?

Enterprise JavaBeans (EJBs) are server-side components written in Java that perform the business logic of an application in multi-tier distributed applications. Typically, an application using EJBs consists of:

An EJB server—EJB servers manage system resources—such as processes, threads, memory and network sessions—on behalf of the applications that run on them. An EJB server must be able to host EJB containers and provide them with these services.
EJB containers that run on the EJB server—An EJB container manages EJB classes and is responsible for making instances of these EJBs available to the application's clients. The container insulates the EJB from the workings of the underlying EJB server and provides transaction services, resource management and security services to the EJB classes it contains.
EJBs that run in those containers—An EJB is a reusable component that implements a business task. It consists of a Java class, home and remote interfaces, a deployment descriptor and any environment settings needed for deployment. Since the EJB container handles the interaction with the server, the EJB focuses only on the business logic of the application.
EJB-enabled clients—At runtime, clients invoke methods on EJBs to perform their server-side processing.

Note: For more information about EJBs, refer to the EJB site at:
```
http://www.oracle.com/technetwork/java/javaee/ejb/index.html
```

What is WebSphere Application Server?

The WebSphere Application Server provides a full-featured distributed application environment, including:

Multi-tier, distributed applications. Multi-tier applications expand the client/server model so that the client interacts with the user; the application server contains the business logic; and the resource manager stores the data. Each tier can consist of multiple machines, working together as a single system.
Server-side components. By implementing your business logic using components, you can reuse components in multiple applications, without additional programming.
Multi-threaded applications. Using threads instead of processes improves application performance.
Database connection pooling. One of the major benefits of multi-tier applications is that the application server maintains the database connections, not the application clients, reducing the number of concurrent connections.
Scalability. The number of users for web-based applications can grow quickly and your deployment strategy must plan for this growth.
Security. By defining your security model, you determine which users can access EJBs.
Web application administration. Website usage logging and analysis tools are available. There is also an optional performance pack to handle caching, load balancing, and file replication for high-volume websites.
HTTP Web Server. An Apache-based HTTP server is available, if one is not already in place.
Java technology support. Java technologies provide an object-oriented and platform-independent environment utilizing open standards for the following application programming interfaces:

How Do Panther and WebSphere Work Together?

In a Panther/WebSphere application, you get the benefit of Panther's development tools working together with IBM's WebSphere Application Server deployment capabilities.

Figure 1-1 The Panther/WebSphere environment combines Panther and WebSphere technologies allowing access to different types of clients and data sources.

Panther's development environment accelerates the creation of application objects—EJBs, client screens— needed in multi-tier, component-based applications. WebSphere Application Server provides the tools for deploying your application on a system designed to manage high-volume, web-based applications.

In the Panther/WebSphere environment, WebSphere Application Server is the EJB server and provides the EJB container—the runtime context for the bean.

Figure 1-2 An EJB client uses the home interface to create the bean before calling the bean's methods, which are described in the remote interface.

Use the Panther editor to build EJBs—session beans that implement business tasks—and to build client screens that call EJBs. Each instance of a session bean is associated with a particular client and is created and destroyed by that client.

Building a Panther/WebSphere Application

Subsequent chapters describe each of the following tasks that are part of designing and building a Panther/WebSphere application. The following flowchart illustrates the tasks involved in this process.

Figure 1-3 Process of developing a Panther/WebSphere application.