AmbiguousDependenciesServlet.java

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import java.io.IOException;
import java.io.PrintWriter;

import javax.inject.Inject;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import test.artifacts.Asynchronous;
import test.artifacts.AsynchronousPaymentProcessor;
import test.artifacts.MockPaymentProcessor;
import test.artifacts.PaymentProcessor;
import test.artifacts.Synchronous;
import test.artifacts.SynchronousPaymentProcessor;
import test.beans.BeanToTestAmbiguousDependencies;

@WebServlet(name = "mytest", urlPatterns = { "/myurl" }, initParams = {
        @WebInitParam(name = "n1", value = "v1"),
        @WebInitParam(name = "n2", value = "v2") })
public class AmbiguousDependenciesServlet extends HttpServlet {

    @Inject
    BeanToTestAmbiguousDependencies tb;

    @Inject
    @Synchronous
    PaymentProcessor synchronousPaymentProcessor;
    @Inject
    @Asynchronous
    PaymentProcessor asynchronousPaymentProcessor;

    public void service(HttpServletRequest req, HttpServletResponse res)
            throws IOException, ServletException {
        PrintWriter writer = res.getWriter();
        writer.write("Hello from Servlet 3.0. ");
        String msg = "n1=" + getInitParameter("n1") + ", n2="
                + getInitParameter("n2");

        if (!tb.testInjection())
            msg += "Alternatives injection and test for availability of other beans via @Any Failed";

        //In the case of ambiguous dependencies such as synchronous and asynchronous payment processors
        //the enabled alternative wins
        boolean qualifierTestSuccess = synchronousPaymentProcessor instanceof MockPaymentProcessor
                && asynchronousPaymentProcessor instanceof MockPaymentProcessor;
        if (!qualifierTestSuccess)
            msg += "Qualifier based injection into Servlet Failed";

        writer.write("initParams: " + msg + "\n");
    }
}