Design Pattern Toolkit

1. What kind of applications can be patterned?

Generally, the applications that can be expressed in terms of a Design Pattern Toolkit pattern are those that are expected to run in "server containers," such as J2EE applications, Web Portals, and Web Services, as well as application components that run against an API such as JDBC, SAX/DOM, Java™ Swing, or the Eclipse Workbench.

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2. Can patterns be written for things not normally considered to be applications?

Yes. A pattern can be written for almost any set of text output of any name and type, even spanning Eclipse projects. For example, there is a sample pattern provided for LDIF files. This pattern takes an application definition describing groups, users, and membership and generates an LDIF file for import into an LDAP directory.

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3. If this toolkit supports model-driven architecture, does that mean that the input XML (the application definition for a pattern) has to be something like UML or XMI?

No. The pattern developer has complete control over the application definition schema and can use elements that match the objects that model the application's design. For example, in the JDBC pattern provided as a sample pattern, the input application definition schema has <table>, <column> and <schema> as its expected elements.

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4. I've installed the Design Pattern Toolkit. Now what do I do?

You can try some of the sample patterns supplied in the /samples directory of this plug-in, you can use patterns that other people have written, or you can develop your own patterns.

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5. The Apply Pattern action can't find any patterns. What's the problem?

The Design Pattern Toolkit looks for patterns in several places. In the preferences window under the Pattern category, you can designate the directory that holds patterns (files of type .patzip). That directory defaults to c:\patzip and should be changed to the directory of your choice.

The Design Pattern Toolkit will also let you apply patterns that you are developing in Pattern projects. You can create a pattern project with File > New > Project... > Design Pattern Toolkit > New pattern project. Finally, patterns that are distributed as part of other Eclipse plug-ins are also listed by the Apply Pattern action.

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6. Where can I find help on using the Design Pattern Toolkit?

The help for the Design Pattern Toolkit can be viewed by selecting Help > Help Contents from within Eclipse. There is a Design Pattern Toolkit topic.

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7. What can I do in a pattern?

The pattern can be thought of as a transformation between the input application definition and the complete set of generated source artifacts. There are template tags that let you transform the application definition into an intermediate XML form and then navigate that XML to drive the generation of source artifacts. Each source artifact is generated as a result of applying the modified application definition to a specific pattern template. Each pattern template contains a set of static, or boilerplate, code interspersed with template tags that direct and define the merging of the application definition with the template.

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8. Someone gave me a pattern to use, but I don't like it. What can I do?

You can import the pattern into an Eclipse pattern project and modify it to meet your needs, or you can create a new pattern that overrides the existing pattern. When you override a pattern, you can perform additional application definition transformations (if you want to use a different schema) or you can override specific pattern templates (both controller and view) to change the way the pattern generates certain resources.

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9. How do you create an Eclipse Java project using a pattern?

The Design Pattern Toolkit has been used in a number of IBM® Software Services for WebSphere® (Enablement) engagements to quickly produce complex applications that conform to a large number of the best known practices and conventions. These applications have been used primarily to demonstrate the application of best known practices to specific customer requirements.

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10. How has the Design Pattern Toolkit been used until now?

The Design Pattern Toolkit has been used in a number of IBM® Software Services for WebSphere® (Enablement) engagements to quickly produce complex applications that conform to a large number of the best known practices and conventions. These applications have been used primarily to demonstrate the application of best known practices to specific customer requirements.

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