Java EE6 - POJO injection

Simplest Possible POJO Injection Example With Java EE 6
http://www.adam-bien.com/roller/abien/entry/simplest_possible_pojo_injection_example

Annotation Type Inject

http://download.oracle.com/javaee/6/api/javax/inject/Inject.html


Contexts and Dependency Injection for the Java EE Platform

http://www.oracle.com/technetwork/articles/javaee/javaee6overview-141808.html#webbeans


TestInject class

package testinject;

import javax.ejb.EJB;
import javax.inject.Named;

import testejb.BackendBeanLocal;
import testservice.MasterDataCacheLocal;

@Named("TestInject")
public class TestInject {
    
    
    public TestInject(){
        System.out.println("TestInject : constructor");
    }

    @EJB
    MasterDataCacheLocal masterDataCache;
    
    @EJB
    BackendBeanLocal service;
    
    public void callService(){
        
        if(masterDataCache.get("dave") == null){
            masterDataCache.store("dave","dave");
        }
        
        System.out.println("TestInject: callService" );
        service.runService();
        
    }

}

Inject POJO in Test Servlet

  @Inject
    TestInject testInject;

protected void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        
        out.println("testInject.callService()<br>");
        testInject.callService();

This file is necessary to force to injection
/testWEB/WebContent/WEB-INF/beans.xml
http://download.oracle.com/javaee/6/tutorial/doc/gjbnz.html

</beans>

TestServlet

package testWEB;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;

import javax.ejb.EJB;
import javax.inject.Inject;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import testinject.TestInject;
import testservice.TestServiceLocal;

/**
 * Servlet implementation class TestServlet
 */
@WebServlet("/TestServlet")
public class TestServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public TestServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    @EJB TestServiceLocal service;
    
    @Inject
    TestInject testInject;
    
    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        PrintWriter out = res.getWriter();
        res.setContentType("text/html");
        
        HttpSession session = req.getSession(true);

        String heading;
        Integer accessCount = new Integer(0);
        if (session.isNew()) {
            heading = "Welcome, Newcomer";
        } else {
            heading = "Welcome Back";
            Integer oldAccessCount = (Integer) session
                    .getAttribute("accessCount");
            if (oldAccessCount != null) {
                accessCount = new Integer(oldAccessCount.intValue() + 1);
            }
        }
        session.setAttribute("accessCount", accessCount);
        
        out.println("service.callService()<br>");
        service.callService();
        
        out.println("testInject.callService()<br>");
        testInject.callService();

        out.println("<H1>This is a password protected resource</H1>");
        out.println("<PRE>");
        out.println("User Name: " + req.getRemoteUser());
        String name = (req.getUserPrincipal() == null) ? null : req
                .getUserPrincipal().getName();
        out.println("Principal Name: " + name);
        out.println("Authentication Type: " + req.getAuthType());
        out.println("Is a Manager: " + req.isUserInRole("AppRole"));
        out.println("</PRE>");
        out.println(
                "<H1 ALIGN=\"CENTER\">" + heading + "</H1>\n" +
                "<H2>Update Servlet!!! Information on Your Session:</H2>\n" +
                "<TABLE BORDER=1 ALIGN=CENTER>\n" +
                "<TR BGCOLOR=\"#FFAD70\">\n" +
                "  <TH>Info Type<TH>Value\n" +
                "<TR>\n" +
                "  <TD>ID\n" +
                "  <TD>" + session.getId() + "\n" +
                "<TR>\n" +
                "  <TD>Creation Time is\n" +
                "  <TD>" + new Date(session.getCreationTime()) + "\n" +
                "<TR>\n" +
                "  <TD>Time of Last Access\n" +
                "  <TD>" + new Date(session.getLastAccessedTime()) + "\n" +
                "<TR>\n" +
                "  <TD>Number of Previous Accesses\n" +
                "  <TD>" + accessCount + "\n" +
                "</TABLE>\n");
        out.println("</BODY></HTML>");
        
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

Application Server log

[#|2011-11-06T22:49:45.979+0100|INFO|glassfish3.1.1|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=17;_ThreadName=Thread-2;|WEB0671: Loading application [testEAR#testWEB.war] at [testWEB]|#]

[#|2011-11-06T22:49:46.002+0100|INFO|glassfish3.1.1|javax.enterprise.system.tools.admin.org.glassfish.deployment.admin|_ThreadID=17;_ThreadName=Thread-2;|testEAR was successfully deployed in 911 milliseconds.|#]

[#|2011-11-06T22:50:30.394+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|TestInject : constructor|#]

[#|2011-11-06T22:50:30.401+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|principal=dave|#]

[#|2011-11-06T22:50:30.404+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|MasterDataCache.initCache|#]

[#|2011-11-06T22:50:30.409+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|MasterDataCache.get dave|#]

[#|2011-11-06T22:50:30.411+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|TestService: masterDataCache.store|#]

[#|2011-11-06T22:50:30.413+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|MasterDataCache.store dave|#]

[#|2011-11-06T22:50:30.413+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|TestService: callService|#]

[#|2011-11-06T22:50:30.415+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|BackendBean: runService|#]

[#|2011-11-06T22:50:30.417+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|MasterDataCache.get dave|#]

[#|2011-11-06T22:50:30.417+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|TestInject: callService|#]

[#|2011-11-06T22:50:30.418+0100|INFO|glassfish3.1.1|javax.enterprise.system.std.com.sun.enterprise.server.logging|_ThreadID=24;_ThreadName=Thread-2;|BackendBean: runService|#]

Dependency Injection (DI) and JNDI

EJB3 in action http://www.manning.com/panda/
Chapter 2.1.2 - Introducing dependency injection In a sense, injection is lookup reversed. As you can see, in the manual JNDI lookup model, the bean explicitly retrieves the resources and components it needs. As a result, component and resource names are hard-coded in the bean. With DI, on the other hand, the container reads target bean configuration, figures out what beans and resources the target bean needs, and injects them into the bean at runtime.

Inversion of Control Containers and the Dependency Injection pattern
http://www.martinfowler.com/articles/injection.html

Create EJBTimer On Weblogic 10.3 using resource injection

Programming the EJB Timer Service
http://edocs.bea.com/wls/docs103/ejb/implementing.html#wp1191405

EJB 3.0 Metadata Annotations Reference
http://edocs.bea.com/wls/docs103/ejb30/annotations.html#wp1425297

Interface TimerService.createTimer
http://java.sun.com/j2ee/1.4/docs/api/javax/ejb/TimerService.html#createTimer%28long,%20long,%20java.io.Serializable%29

@Local
@Remote
@Stateless(mappedName = "ejb/TestTimer")
public class TestTimerEJB implements TestTimer {


    // resources that the container will inject
    @Resource
    private TimerService timerService;
    
    //inject data source 
    @Resource(mappedName="jdbc/MyDataSource")
    private javax.sql.DataSource datasource;  

@Timeout
public void execute(Timer timer) {
    System.out.println("Hi from TestTimerEJB timer");
}