package example; import javax.inject.Inject; import javax.enterprise.inject.Any; import javax.enterprise.inject.Instance; import javax.servlet.*; import javax.servlet.http.*; import java.io.*; public class SetServlet extends HttpServlet { // service pattern private @Inject MyService _service; // resource pattern private @Inject @Blue MyResource _blueResource; private @Inject @Red MyResource _redResource; // plugin/extension pattern private @Inject @Any Instance _resources; // startup pattern private @Inject StartupResourceBean _startupResource; @Override public void service(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html; charset=utf-8"); PrintWriter out = response.getWriter(); String color = request.getParameter("color"); // service and resource patterns if ("red".equals(color)) _service.setMessage(_redResource.getMessage()); else if ("blue".equals(color)) _service.setMessage(_blueResource.getMessage()); writeHeader(out); // service pattern out.println("

Service Pattern

"); out.println(""); out.println("
BindingValue"); out.println("
@Inject MyService" + _service); out.println("
"); // resource pattern out.println("

Resource Pattern

"); out.println(""); out.println("
BindingValue"); out.println("
@Red MyResource" + _redResource); out.println("
@Blue MyResource" + _blueResource); out.println("
"); // plugin/extension pattern out.println("

Plugin/Extension Pattern

"); out.println("
    "); for (MyResource resource : _resources) { out.println("
  1. " + resource); } out.println("
"); // startup pattern out.println("

Startup Pattern

"); out.println(""); out.println("
BindingValue"); out.println("
@Inject StartupResourceBean" + _startupResource); out.println("
"); writeFooter(out); } private void writeHeader(PrintWriter out) throws IOException { out.println("CanDI Pattern Tutorial: SetServlet"); out.println(""); out.println("
"); out.println(" docs"); out.println(" / examples"); out.println(" / CanDI pattern tutorial"); out.println("
"); out.println("

CanDI Pattern Tutorial: SetServlet

"); out.println("

The SetServlet demonstrates the four Java Injection"); out.println("patterns by injecting the services and resources and"); out.println("displaying their values in tables."); out.println("

Click on the 'SetServlet blue' link, the"); out.println("'SetServlet red' link, and the 'SetServlet' link "); out.println("to check that both servlets share the same MyService"); out.println("instance"); out.println("

Demo Links

"); out.println(""); } private void writeFooter(PrintWriter out) throws IOException { out.println("

Demo Architecture

"); out.println(""); out.println("

SetServlet Code

"); out.println("
");
    out.println("public class SetServlet extends HttpServlet {");
    out.println("  // service pattern");
    out.println("  private @Inject MyService _service;");
    out.println();
    out.println("  // resource pattern");
    out.println("  private @Red MyResource _redService;");
    out.println("  private @Blue MyResource _blueService;");
    out.println();
    out.println("  // plugin/extension pattern");
    out.println("  private @Any Instance<MyResource> _resources;");
    out.println();
    out.println("  // startup pattern");
    out.println("  private @Inject StartupResourceBean _startupResource;");
    out.println();
    out.println("  ...");
    out.println("}");
    out.println("
"); } }