README.md

v-guice

This project provides the machinery necessary to create Vaadin applications using Guice for dependency injection. This project is really a distilled version of https://github.com/davidsowerby/v7/.

Version 2.0 now supports Vaadin 8.1+.

To Guice-up your Vaadin project, you'll need to do the following:

1. Create your injectable UI, by extending ScopedUI:

    @Theme("runo")
    public class GuicedUI extends ScopedUI  {
   
    	@Inject
    	public GuicedUI(InjectableObject obj) {
   
    	}
   
    	@Override
    	protected void init(VaadinRequest request) {
    	}
    }
   

2. Create your Guice servlet module, where servlet and filter mappings are set up:

    public class GuicedServletModule extends ServletModule {
   
        @Override
    	protected void configureServlets() {
    	
    		serve("/*").with(VGuiceApplicationServlet.class, getServletParams());
    	
    	}
    }
   

3. Create the listener which bootstraps the whole web app. Here you tell the UIScopeModule about your GuicedUI created in step 1. See https://code.google.com/p/google-guice/wiki/Servlets for full instructions and background.

    public class GuiceContextListener extends GuiceServletContextListener {
    	@Override
    	protected Injector getInjector() {
    		return Guice.createInjector(new UIScopeModule(GuicedUI.class), new GuicedServletModule());
    	}
    }
   

You need to tell your servlet container about the listener in your web.xml file by including this configuration:

	<filter>
		<filter-name>guiceFilter</filter-name>
		<filter-class>com.google.inject.servlet.GuiceFilter</filter-class>
	</filter>

	<filter-mapping>
		<filter-name>guiceFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

	<listener>
		<listener-class>com.example.GuiceContextListener</listener-class>
	</listener>

Note that if you are using servlet 3.0 you can annotate your GuiceServletContextListener subclass with @WebListener instead of specifying it in web.xml.

Henceforth, any objects injected into your UI can also have their dependencies injected. These can be scoped to the UI level or higher (e.g. Session scope or Singleton). UIScope essentially means "Browser window scope".