Make PippoFilter.createApplication protected

[decebals]

Now, this method is private and the modification is simple.
The impact is big. You can control how an application instance is created (by default an application instance is created using applicationClassName init parameter supplied in web.xml).
For example, this modification allows me to use a PippoApplication defined as Spring bean in Spring configuration.

The steps are:

• create a custom filter that knows how to retrieves the Pippo application bean from Spring

public class SpringPippoFilter extends PippoFilter {

    @Override
    protected void createApplication(FilterConfig filterConfig) {
        ServletContext servletContext = filterConfig.getServletContext();
        ApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext);
        Application application = (Application) applicationContext.getBean("pippoApplication");
        setApplication(application);
    }

}

• define Pippo application as bean in Spring configuration

@Configuration
public SpringConfig {

    @Bean
    public FrontendApplication pippoApplication() {
        return new FrontendApplication();
    }

    @Bean
    public ProductService productService() {
        return new DefaultProductService();
    }

    // other beans injected via @Autowire in pippoApplication

}

• inject in your Pippo application other components managed by Spring (for example ProductService in my case)

@Component
public class FrontendApplication extends Application {

    @Autowired
    private ProductService productService;

    @Override
    protected void onInit() {
        getRouter().ignorePaths("/admin"); // Wicket application

        // send 'Hello World' as response
        GET("/", routeContext -> routeContext.send("Hello World"));

        GET("/products", routeContext -> routeContext.text().send(productService.count()));
    }

}

• specify where Spring keeps configuration (SpringConfig in our case) and specify that I want to use my custom filter SpringPippoFilter instead of default PippoFilter (that comes with pippo-core)
  [web.xml]

    <context-param>
        <param-name>contextClass</param-name>
        <param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>
    </context-param>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>SpringConfig</param-value>
    </context-param>

    <filter>
        <filter-name>pippo.filter</filter-name>
        <filter-class>SpringPippoFilter</filter-class>
    </filter>

Sure this modification is not valuable is you don't use the web.xml standard descriptor file to specify your Pippo application.

[decebals]

Done in 2b5335c.

[decebals]

To add more details to my specific use case, I need to replace the frontend part of a legacy application built with Wicket, with PIppo (both applications built with Pippo and Wicket must coexist and share the same Spring beans).
My usual mode to initiate and start a Pippo application configured with Spring is very simple:

public class Launcher {

    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext(SpringConfiguration.class);
        Application application = context.getBean(FrontendApplication.class);
        Pippo pippo = new Pippo(application);
        pippo.start();
    }

}

[mhagnumdw]

@decebals, I read your comments.

Could you please explain to me what is the point of joining Pippo with Spring? I would like to understand more about this possible link. Thank you!

[decebals]

@mhagnumdw
Pippo comes already with support builtin for all import DI containers (Spring, Guice and CDI).
The Pippo modules that add support for these DIs (Dependency Injection) are available at https://github.com/pippo-java/pippo/tree/master/pippo-controller-parent (pippo-spring, pippo-guice, ...).
We have also a documentation that explains integration with Spring.

Now I see that for example that the integration with Spring is available only if you use controllers.
But, I want to use Spring DI when I use plain routes (instead of controllers) also. And to do that I use the approaches explained in #538 (comment) (if I use web.xml) and #538 (comment) (if I use Pippo wrapper that comes with pippo-core).
If you need more information, please let me know.