Templates

The templates can be used to generate assets — such as code — out of your Object Model. Examples can be java interfaces and classes, but also configuration files (like Liquibase changesets) or even documentation.

Below is a simple implementation of a template:

ExampleTemplate.java

import org.xomda.template.Template;
import org.xomda.template.TemplateContext;

public class TestTemplate implements Template<Object> {

    @Override
    public void generate(Object o, TemplateContext ctx) {
        System.out.println("It works!");
    }

}

The templates should implement the org.xomda.template.Template interface, provided by XOMDA.

Java Code Template

There are helpers to help you generate Java classes. The example below generates a Java interface; it's borrowed straight from the XOMDA codebase.

First off all, we start by creating a new JavaClassWriter. This special context will assist you with indenting, tabbing, writing Javadoc and more.

Example template

The following Template will generate java beans, interfaces and enums.

GenerateEntityTemplate.java

public class GenerateEntityTemplate extends PackageTemplate {

    @Override
    public void generate(final Entity entity, final TemplateContext context) throws IOException {
        String javaInterface = TemplateUtils.getJavaInterfaceName(entity);
        String javaClass = TemplateUtils.getJavaBeanName(entity);
        PojoWriter
                .createInterface(context.cwd(), javaInterface)
                .write(entity);
        PojoWriter
                .create(context.cwd(), javaClass)
                .withImplements(javaInterface)
                .write(entity);
    }

    @Override
    public void generate(final org.xomda.model.Enum enm, final TemplateContext context) throws IOException {
        EnumWriter.create(context.cwd(), TemplateUtils.getJavaEnumName(enm))
                .write(enm);
    }

}

JavaImportService

Inside a JavaClassWriter-instance, there's an instance of a JavaImportService. This is a special class which will assist you with managing class-level imports.

When writing the output, the JavaClassWriter will take care of declaring the package and printing the imports. During the generation you can add imports to the JavaImportService and it will return the either the fully qualified class name or the simple one, depending on the circumstances.

You can use addImport, addStaticImport and addGenericImport to add imports to the service.