Coding the Enterprise Bean

The enterprise bean in this example needs the following code:

• Remote business interface

• Enterprise bean class

Coding the Business Interface

The business interface defines the business methods that a client can call. The business methods are implemented in the enterprise bean class. The source code for the Converter remote business interface follows.

package com.sun.tutorial.javaee.ejb;

import java.math.BigDecimal;
import javax.ejb.Remote;

@Remote
public interface Converter {
    public BigDecimal dollarToYen(BigDecimal dollars);
    public BigDecimal yenToEuro(BigDecimal yen);
}

Note the @Remote annotation decorating the interface definition. This lets the container know that ConverterBean will be accessed by remote clients.

Coding the Enterprise Bean Class

The enterprise bean class for this example is called ConverterBean. This class implements the two business methods (dollarToYen and yenToEuro) that the Converter remote business interface defines. The source code for the ConverterBean class follows.

package com.sun.tutorial.javaee.ejb;

import java.math.BigDecimal;
import javax.ejb.*;

@Stateless
public class ConverterBean implements Converter {
    private BigDecimal yenRate = new BigDecimal("115.3100");
    private BigDecimal euroRate = new BigDecimal("0.0071");

    public BigDecimal dollarToYen(BigDecimal dollars) {
        BigDecimal result = dollars.multiply(yenRate);
        return result.setScale(2, BigDecimal.ROUND_UP);
    }

    public BigDecimal yenToEuro(BigDecimal yen) {
        BigDecimal result = yen.multiply(euroRate);
        return result.setScale(2, BigDecimal.ROUND_UP);
    }
}

Note the @Stateless annotation decorating the enterprise bean class. This lets the container know that ConverterBean is a stateless session bean.