WebSphere Studio Application Developer Version 5 Programming Guide part 11 doc

ProjectsThis chapter introduces the project types and some of the main terms used in Application Developer... J2EE architectureThe Java 2 Platform, Enterprise Edition J2EE is a robust su

Figure 3-21 CVS Repository Exploring perspective

Files that exist in the repositories can be viewed by double-clicking them in a branch or version This opens the version of the file specified in the file editor, located at the top right of the workspace

򐂰 CVS Resource History view—Displays more detailed history of each file

This view provides a list of all the revisions of a resource in the repository From this view you can compare two revisions, replace (get sticky), or revert the corresponding workspace file to the revision (get contents), or open an editor on a revision

More details about using the CVS Repository Exploring perspective can be found

in Chapter 22, “Using Concurrent Versions System” on page 701

Install/Update perspective

The Install/Update perspective (Figure 3-22) allows you to check to see whether there are updates for a product's existing features Working with this perspective usually requires access to the Internet

Figure 3-22 Install/Update perspective

The Install/Update perspective contains these views:

򐂰 Install Configuration view—This view allows you to manage your

workspace configuration The Current Configuration folder shows which local installation locations are part of the workspace configuration, and which features are installed in those locations The Configuration History folder shows a history of changes made to your workspace configuration The Saved Configurations folder show any configurations that were preserved

򐂰 Feature Updates view—This view allows you to locate and install new

features and feature updates The view contains three standard folders The Sites to Visit folder contains update sites pre-configured by the product you are using The Available Updates is a built-in search results folder used for searching update sites The My Computer folder is a file explorer that can be used to navigate to updates located in the file system

򐂰 Preview view—This view displays detailed information about the current

active selection Its content changes according to your selection

For information about how to work with the Update Manager consult Appendix A,

“Product installation” on page 785

Plug-in Development perspective

You can develop your own Application Developer tools by using the Plug-in Development Environment (PDE) The PDE provides a set of platform extension contributions (views, editors, perspectives, etc.) that collectively streamline the process of developing plug-ins inside the Workbench

In this book we do not describe how to develop plug-ins for Application Developer Figure 3-23 shows the Plug-in Development perspective

Figure 3-23 Plug-in Development perspective

To learn more about plug-in development, refer to The Java Developer’s Guide

to Eclipse (see “Other publications” on page 818)

In this chapter we described the perspectives and views that you use with Application Developer to perform your tasks

Chapter 4. Projects

This chapter introduces the project types and some of the main terms used in Application Developer

򐂰 J2EE architecture:

– EAR files – WAR files – JAR files

򐂰 Projects and folders

򐂰 Project types:

– Simple project – Java project – Web project – Enterprise Application project – EJB project

– Application Client project – Server project

򐂰 Creating a new project

4

J2EE architecture

The Java 2 Platform, Enterprise Edition (J2EE) is a robust suite of middle-ware application services for server side application development J2EE is an extension of the Java 2 Platform, Standard Edition (J2SE)

J2EE makes all Java enterprise APIs and functionality available and accessible

in a well integrated fashion This helps in simplifying complex problems in the development, deployment, and management of multi-tier, server-centric enterprise solutions

Figure 4-1 shows an overall view comprising the different J2EE technologies

Figure 4-1 J2EE architecture diagram

Web containers and EJB containers

Containers are basically run-time environments that provide components with specific services For example, Web containers provide run-time support to clients by processing requests through invoking JSPs and servlets and returning results from the components to the client Similarly, EJB containers provide

J2SE

Applet Container

Applet

Database

Application Client Container

Application Client

J2SE

WebSphere

Web Container

J2SE

Java Mail JAF

EJB Container EJB

J2SE

Java Mail JAF

HTTP SSL HTTP SSL

automated support for transaction and state management of EJB components,

as well as look up and security services

For additional information regarding the J2EE architecture and its technologies, consult the J2EE specification on Sun’s Web Site:

http://java.sun.com/j2ee

EAR files

Enterprise archive (EAR) files represent a J2EE application that can be deployed

in a WebSphere application server EAR files are standard Java archive files and have the file extension ear EAR files also contain a deployment descriptor (an XML file) that describes the contents of the application and contains instructions for the entire application, such as security settings to be used in the run-time environment

An EAR file has the following modules (zero, one, or more of each type):

򐂰 Web modules

򐂰 EJB modules

򐂰 Application client modules

򐂰 Utility JAR files required by other modules

WAR files

Web archive (WAR) files contain all the components of a Web application These components are usually:

򐂰 HTML files

򐂰 CSS files

򐂰 JSP files

򐂰 Servlets

򐂰 Compiled Java files

򐂰 Images

JAR files

The Java archive (JAR) file format allows you to store multiple files into a single archive file Typically, a JAR file contains the class files and additional resources associated with applets and applications

EJB modules and utility modules are packaged as JAR files

Projects and folders

Application Developer organizes all resources into projects

A project in Application Developer is the top-level construct for organizing the different resources It contains files as well as folders In the Workbench you can create different kinds of projects, and they will have a different structure

Unless not specified differently, projects are created in the workspace directory

of Application Developer’s installation folder Also, the metadata is stored in the workspace directory The metadata directory of a workspace directory stores important information about the workspace structure, such as a project’s reference or a resource’s properties

A project is either open or closed When a project is closed, it cannot be changed

in the Workbench and it cannot be referenced from other projects The resources

of a closed project do not appear in the Workbench, but they do reside in the local file system

Application Developer’s project types

Application Developer provides different project types for different tasks

Simple project

A Simple project in Application Developer does not have any default folders and does not have an associated builder The files stored inside the project are not compiled when you select to rebuild all projects in the Workbench

We will use a simple project in Chapter 6, “Developing database applications” on page 139

Java project

A Java project contains Java packages and Java code as java files and class

files Java projects have an associated Java builder that incrementally compiles Java source files as they are changed Java projects can be exported as JAR files or into a directory structure

Tip: Closed projects require less memory Because they are not examined

during builds, closing a project can improve the build time

Java projects are used for stand-alone applications or to build utility JAR files for

an enterprise application A detailed example of how to create a new Java project is provided in “Creating and working with a Java project” on page 94

Enterprise Application project

Enterprise Application projects contain references to the resources needed for enterprise applications and can contain a combination of Web modules, EJB modules, application client modules, and JAR files

An Enterprise Application project is deployed in the form of an EAR file In Application Developer, the modules in an Enterprise Application project are mapped to other J2EE projects The mapping information is stored in metadata files within the Enterprise Application project The metadata files are used for exporting the project to an EAR file, and for running the project on the server Application Developer mirrors the layout of a J2EE enterprise application modules with matching project types For each type of module, a project type tailored for that purpose is provided (Figure 4-2)

Figure 4-2 Application Developer projects for J2EE

We will create an Enterprise Application project together with a Web project in Chapter 7, “Developing Web applications” on page 179

EAR Project

EJB Project

Web Project

Client Project

EJB

Web DD

Application DD

HTML, GIF, etc.

Enterprise Bean

Client Class Servlet JSP

EJB Module JAR file

Web Module WAR file

Client Module JAR file

DD = Deployment Descriptor

J2EE Application EAR file

web.xml application.xml

ejb-jar.xml

Application Developer