Fabric3 supports wiring services to Servlets and JSPs in a web application by treating web applications as components. In this chapter, we cover how to implement a web component and wire it to other services in a domain.

Implementing Web Components

Web components are web applications (WARs) with additional SCA artifacts that allow Servlets and JSPs to be wired to services in a domain.

Web components do not need to be explicitly defined - a WAR is sufficient for Fabric3 to deploy it as a web app. However, if you need to specify configuration such as the URL path, you must create a composite with an implementation.web:

<component name="calculator">
   <implementation.web/>
</component>

WAR contribution composites are typically placed under /WEB-INF although the may be located anywhere in the contribution archive. When deployed, the web application context for the above component will be <runtime ip>:<port>/calculator.

In the previous example, a reference to the CalculatorService was made available to the web application for injection onto servlets and JSPs. To inject the reference on a Servlet, use the @Reference annotation:

public class CalculatorServlet extends HttpServlet {

   @Reference
   protected CalculatorService calculatorService;

   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      // ...
   }
}

Configuring the Web Context Path

The web context URL is calculated by using the component URI. For example, a web component named "WebComponent" will be available from http://<server address>/WebComponent. It is good practice to specify a relative context path that differs from the component name. To do this, use the implementation.web/@uri attribute:

<component name="WebComponent">
   <implementation.web uri="webapp"/>
</component>

In the above example, the web context URL will be http://<server address>/webapp

Integrating Web UI Frameworks

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Enabling Web Component Support

Web component support is enabled by installing the web profile in any of the Fabric3 runtimes.