THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Sample of a Stateless Session Bean in EJB 3.0
This sample will demonstrate the following new features from EJB 3.0
- Elimination of the requirement for EJB component interfaces for session beans. The required business interface for a session bean can be a plain Java interface rather than an EJBObject, EJBLocalObject, or java.rmi.Remote interface.
- Elimination of the requirement for home interfaces for session beans.
- Encapsulation of environmental dependencies and JNDI access through the use of annotations, dependency injection mechanisms, and simple lookup mechanisms.
- Introduction of Java metadata annotations to be used as an alternative to deployment descriptors.
Calculator Implementation
Calculator.java: A stateless session bean that implements a simple java interface instead of an EJB component interface like EJBObject, EJBLocalObject or java.rmi.Remote. By annotating this class as a @Stateless session there is no need for a deployment descriptor to describe it separately. This class implements both a local and remote business interface, namely CalculatorLocal and CalculatorRemote.
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package org.apache.geronimo.samples.calculator;
import java.io.IOException;
import javax.ejb.EJB;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.geronimo.samples.slsb.calculator.CalculatorLocal;
public class CalculatorServlet extends HttpServlet {
@EJB
private CalculatorLocal calc = null;
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
try {
String firstNumber = req.getParameter("firstNumber");
String secondNumber = req.getParameter("secondNumber");
String operation = req.getParameter("operation");
int firstInt = (firstNumber == null) ? 0 : Integer.valueOf(firstNumber).intValue();
int secondInt = (secondNumber == null) ? 0 : Integer.valueOf(secondNumber).intValue();
if ( "multiply".equals(operation) ) {
req.setAttribute("result", calc.multiply(firstInt, secondInt));
}
else if ( "add".equals(operation) ) {
req.setAttribute("result", calc.sum(firstInt, secondInt));
}
System.out.println("Result is " + req.getAttribute("result"));
getServletContext().getRequestDispatcher("/sample-docu.jsp").forward(req, resp);
}
catch ( Exception e ) {
e.printStackTrace();
throw new ServletException(e);
}
}
}
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Deployment Plans
The structure of the deployable should look like the following:
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