Jakarta ee @TransactionAttribute有什么用途

在下面的MDB代码片段中，

@TransactionAttribute（TransactionAttributeType.NOT_SUPPORTED）

注释？为什么要保持班级水平

import javax.ejb.*;
import javax.jms.Message;
import javax.jms.TextMessage;
import javax.jms.JMSException;
import javax.ejb.MessageDriven;
import javax.jms.MessageListener;
import javax.ejb.ActivationConfigProperty;
import org.jboss.ejb3.annotation.ResourceAdapter;

@MessageDriven( name="MyMDB",
        activationConfig = 
        { 
            @ActivationConfigProperty(propertyName = "destinationType",propertyValue = "javax.jms.Queue"),
            @ActivationConfigProperty(propertyName = "useJNDI", propertyValue = "false"),
            @ActivationConfigProperty(propertyName = "hostName", propertyValue = "MQ.HOST.NAME"),
            @ActivationConfigProperty(propertyName = "port", propertyValue = "MQ.PORT"),
            @ActivationConfigProperty(propertyName = "channel", propertyValue = "MQ.CHANNEL.NAME"),
            @ActivationConfigProperty(propertyName = "queueManager", propertyValue = "MQ.QUEUE.MANAGER"),
            @ActivationConfigProperty(propertyName = "destination", propertyValue = "MQ.QUEUE.NAME"),
            @ActivationConfigProperty(propertyName = "transportType", propertyValue = "MQ.CLIENT")
        }) 
@ResourceAdapter(value = "wmq.jmsra.rar")
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)

public class MyMDB implements MessageListener{

    public void onMessage(Message message) {
        TextMessage textMessage = (TextMessage) message;
        try {
            System.out.println("nnt Message Received by MDB : "+ textMessage.getText());
        } catch (JMSException e) {
            e.printStackTrace();
        }
    }
}

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您包含的代码段表示MDB的声明性事务配置，它告诉容器应该如何管理此MDB的事务

我找不到比java transaction design strategy book中的引用更好的解释该属性的方法：

NotSupported属性（Spring中不支持传播）告诉容器所调用的方法不使用事务。如果事务已经启动，它将被挂起，直到方法完成。如果不存在任何事务，容器将调用该方法而不启动事务