7.7.4. Transaction Behavior of EJB Invocations

Transaction attributes for distributed EAP applications need to be handled in a way as if the application is called on the same server. To discontinue a transaction, the destination method must be marked REQUIRES_NEW using different interfaces.

To invoke EJB session beans with an EAP 6 standalone client, the client must have a reference to the InitialContext object while the EJB proxies or UserTransaction are used. It is also important to keep the InitialContext object open while EJB proxies or UserTransaction are being used. Control of the connections will be inside the classes created by the InitialContext with the properties.

package org.jboss.as.quickstarts.ejb.multi.server;

import java.util.Date;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.naming.Context;
import javax.naming.InitialContext;

import org.jboss.as.quickstarts.ejb.multi.server.app.MainApp;
import org.jboss.ejb.client.ContextSelector;
import org.jboss.ejb.client.EJBClientConfiguration;
import org.jboss.ejb.client.EJBClientContext;
import org.jboss.ejb.client.PropertiesBasedEJBClientConfiguration;
import org.jboss.ejb.client.remoting.ConfigBasedEJBClientContextSelector;

public class Client {

/**
* @param args no args needed
* @throws Exception
*/
    public static void main(String[] args) throws Exception {
        // suppress output of client messages
        Logger.getLogger("org.jboss").setLevel(Level.OFF);
        Logger.getLogger("org.xnio").setLevel(Level.OFF);
        
        Properties p = new Properties();
        p.put("remote.connectionprovider.create.options.org.xnio.Options.SSL_ENABLED", "false");
        p.put("remote.connections", "one");
        p.put("remote.connection.one.port", "4447");
        p.put("remote.connection.one.host", "localhost");
        p.put("remote.connection.one.username", "quickuser");
        p.put("remote.connection.one.password", "quick-123");

        EJBClientConfiguration cc = new PropertiesBasedEJBClientConfiguration(p);
        ContextSelector<EJBClientContext> selector = new ConfigBasedEJBClientContextSelector(cc);
        EJBClientContext.setSelector(selector);

        Properties props = new Properties();
        props.put(Context.URL_PKG_PREFIXES, "org.jboss.ejb.client.naming");
        InitialContext context = new InitialContext(props);

        
        final String rcal = "ejb:jboss-ejb-multi-server-app-main/ejb//" + ("MainAppBean") + "!" + MainApp.class.getName();
        final MainApp remote = (MainApp) context.lookup(rcal);
        final String result = remote.invokeAll("Client call at "+new Date());

        System.out.println("InvokeAll succeed: "+result);
    }

}

The following example shows how to get UserTransaction reference on a standalone client:

import org.jboss.ejb.client.EJBClient;
import javax.transaction.UserTransaction;
.
.
    Context context=null;
    UserTransaction tx=null;
    try {
      Properties props = new Properties();
      // REMEMBER: there must be a jboss-ejb-client.properties with the connection parameter
      //           in the clients classpath
      props.put(Context.URL_PKG_PREFIXES, "org.jboss.ejb.client.naming");
      context = new InitialContext(props);  
      System.out.println("\n\tGot initial Context: "+context);
      tx=EJBClient.getUserTransaction("yourServerName");
      System.out.println("UserTransaction = "+tx.getStatus());
      tx.begin();
      // do some work
      ...
    }catch (Exception e) {
      e.printStackTrace();
      tx.rollback();
    }finally{
      if(context != null) {
        context.close();
      }
    }