IDE Features for Enterprise Development

The base JDT provides wizards for generating common Java artifacts such as classes and interfaces. Installing MyEclipse enhances the Eclipse workbench with an additional set of wizards that target J2EE components.

The wizards available include project-level wizards for generating Web applications (WAR), EJB components (JAR), and enterprise application (EAR) deployments. MyEclipse also adds wizards for generating code-level artifacts, including support for generating the following:

• Session, entity, and message-driven beans using XDoclet

• Hibernate mapping files

• Web components for the Apache Struts framework

• Standard Web components such as JSP files, HTML pages, and servlets

• XML documents and schemas

Chapter 6 covers XDoclet, and Chapter 7 introduces Hibernate.

Figure 13-2 shows the MyEclipse EJB Wizard, used for generating XDoclet based EJB components.

The EJB wizard provided by MyEclipse is template based. From the templates available, enterprise bean types of session, entity, and message-driven beans can be autogenerated. Note that the code generated is XDoclet based, and the code wizard generates a single bean implementation adorned with XDoclet annotations.

Design options for working with EJB technology are discussed in Chapter 4.

Editor Support for Multiple File Types

The editor is the tool around which the workbench revolves. A powerful code editor contributes immensely to developer productivity. In this regard, the Eclipse Java editor is very advanced and offers a number of time saving features. As an example, here are some of the features from the Eclipse editor's source menu that you may find particularly useful.

Organize imports.

This operation neatly orders all import statements and removes all redundant import declarations.

Add import.

Automatically creates an import declaration for the referenced type.

Format.

Arranges, or beautifies, the code based on a specified layout configuration. Using a common source formatter is a way to ensure compliance with company coding standards.

Override/implement methods .

Code wizard for selecting the methods of a superclass or interface to override or implement. This feature both saves time and increases accuracy by removing the opportunity for inadvertently creating a new method in a deriving class with a typing error.

Generate getters and setters.

This operation removes the tedium of implementing getters and setters for class attributes.

Surround with try/catch block.

Wraps a code selection with a try/catch block and explicitly catches all exceptions types. It also adds import declarations for the necessary exception types.

You should expect most Java development tools to offer similar time saving features.

Tip

Learning the keyboard mappings for invoking these features without having to resort to pointing and clicking with the mouse makes coding a faster process.

J2EE applications require editor support for file types other than Java source. A typical J2EE project could comprise the following:

• JSPs, HTML pages, and style sheets

• SQL scripts

• Deployment descriptors

• Property files

• Velocity templates

• Ant build files

• XML documents and schemas

The editor should help us to quickly and accurately write files of all these types and should afford features such as context-sensitive help, syntax highlighting, and code assist (sometimes called code completion).

The Apache Velocity template engine is covered in Chapter 6.

Note

Code assist , or code completion , is the ability of the editor to display context-sensitive information relating to a particular element in the editor. For example, in the Java editor, a code assist feature would prompt the developer with a list of the available methods for an instance variable of a given type. This functionality is given various names by various IDE vendors . This chapter uses the Eclipse term code assist .

The plug-in model of the Eclipse platform makes it ideally suited for dealing with the various file types of J2EE projects. One primary file type not directly supported by Eclipse is JSP. Here, the MyEclipse plug-in adds JSP editor support, providing code assist and syntax highlighting features, and allows the JSP to be syntax-checked and previewed prior to deployment.

Ant Integration

A prerequisite for any IDE is its ability to integrate with Apache Ant for performing build tasks . An IDE is an unsuitable tool for constructing a reliable and repeatable build process because most development platforms lack the functionality to cover all of the eventualities required of a build system. For the majority of projects, the Apache Ant build utility is used for this purpose. In order for an IDE to integrate with the build process, it must be able to invoke Ant build file targets directly.

The Apache Ant build utility is described in Chapter 12.

The ability to integrate an Ant build file into the IDE is especially significant if code generation tools such as AndroMDA and XDoclet form an integral part of the build process, as these tools require Ant for invocation.

The MDA tool AndroMDA is covered in Chapter 8.

The Eclipse developers recognize the importance of Ant's role in Java software engineering and ensure that Ant is well supported by the Eclipse workbench. No additional plug-in is required to support Ant integration.

Figure 13-3 illustrates the Ant view, which forms an integral part of the Eclipse workbench.

The Ant view lists all targets in a build file. Build targets can be invoked directly from the workbench using the Ant view. All output generated by Ant is written to the Eclipse workbench's console.

For writing build files, the Eclipse workbench comes with an Ant file-aware editor, which can be associated with all XML file types and provides syntax coloring and code assist for Ant tasks.

This level of integration with Ant makes it possible to write and run build files within the confines of the Eclipse workbench, thereby providing a single environment for project development work.

Working with Code Generators

If a project is using a code generator, then the chosen IDE should both integrate with the code generator and work with the generated code.

A major criterion for integrating the IDE with a code generator is the ability of the IDE to invoke the generator by executing targets in an Ant build file. As we learned in the previous section, Eclipse is very accomplished in this area. Furthermore, the IDE should be able to contend with multiple source paths, because it is good practice to output generated source to a different directory than that of handwritten code. This is possible with Eclipse because Java projects may define multiple source paths.

Velocity Templates

For working with template-driven code generators, it is desirable for the IDE to provide support for editing the template files. An open source editor for Velocity templates is available for Eclipse. The plug-in Veloedit can be downloaded from http://veloedit. sourceforge .net.

Figure 13-4 shows Veloedit editing an AndroMDA cartridge template. The editor supports both syntax highlighting and code assist for Velocity files.

Velocity is becoming widely used for code generation, so the Veloedit plug-in enjoys a high number of downloadscurrently, about a thousand downloads a month, which is a significant amount.

XDoclet

The MyEclipse plug-in makes extensive use of XDoclet for generating J2EE components. As we have seen, the EJB wizard generates a bean class annotated with XDoclet attributes.

MyEclipse extends the workbench to ensure XDoclet is well supported and adds code-assist support to the editor for the embedded XDoclet tags. Execution of the XDoclet engine for a MyEclipse project is controlled by a project Ant build file named xdoclet-build.xml . The contents of this build file should not be edited directly. Instead, MyEclipse associates the XDoclet settings with the properties of the EJB project. These properties can be accessed by right-clicking on the project and selecting the Properties menu item. Figure 13-5 displays the various XDoclet properties dialog used for controlling code generation in the project.

Warning

The setting for the destDir attribute that specifies the location of generated source defaults to the same location as the Java source directory.

Accepting this configuration would see generated source mixed up with handwritten code. In line with code generation best practice, you should consider changing this setting to a directory dedicated to holding the generated source. Add this new directory as a source path to your Eclipse project.

Having established a suitable configuration, the XDoclet build script is run via a MyEclipse menu item, available by right-clicking on the project in the package explorer view.

Server Control and Application Deployment

To operate as a fully integrated environment, the IDE must have the capability to deploy J2EE applications. It should also offer the functionality to control the target J2EE server, allowing the developer to start and stop the server without the need to leave the IDE.

Note

These integration features require the IDE to keep pace with new versions of the different application servers. You must also check that your chosen IDE or Eclipse plug-in supports your particular application server.

Eclipse relies on plug-in tools for incorporating this functionality into the workbench. For deployment, MyEclipse adds a deployment wizard to the workbench that enables J2EE modules to be deployed to a number of J2EE server types. Figure 13-6 shows the MyEclipse deployment dialog with a J2EE EAR project selected. The packaged application targets instances of the JBoss and WebLogic servers. For each server selected, you may specifying the deployment type. From the example deployment setup in Figure 13-6, an exploded deployment is specified for WLS, while for JBoss the application is deployed as an EAR file. The type of deployment selected depends on what the application server supports.

MyEclipse allows J2EE servers to be configured within the IDE and adds toolbar items to enable each configured server to be started or stopped from within the Eclipse workbench. This level of integration between application server and IDE provides for the rapid transition of newly written code into a running state, where it can be tested and debugged .

Modeling Support

Eclipse's use of plug-in tools enables the integration of UML modeling tools into the workbench. A number of modeling tools are available as Eclipse plug-ins. Omondo offers Eclipse-UML, available from http://www.omondo.com. In addition, Borland produces an Eclipse modeling tool as part of its Together family of products; see http://www.borland.com.

Chapter 5 provides an overview of the main UML diagrams and discusses modeling tools.