This chapter discusses the types and JNDI default binding names of resources, for which a client container performs dependency injection. It also describes security and transaction services that can be used by application clients and clients that run without a client container.

If you execute a JEUS client without using a client container, the client cannot use the dependency injection service of the client container.

With security settings, you can execute JEUS's various services. With transaction functions, you can manage the resources and applications as global transactions.

This section describes injection details common to application clients, web applications, and EJB applications.

Injection can be performed for resources such as an environment variable, which can be mapped to an EJB object. In general, a resource's name can be found in java:comp/env context, a JNDI context of the application component. Because the actual resource is bound to the JNDI global context, you need to know the global binding name.

Resources have their own JNDI global binding names. The JNDI global binding name of an EJB application should be specified by one of the following methods:

To obtain an EJB through JNDI without a client container, it is necessary to understand the rules for setting the default JNDI name. Because it is hard for a developer to know to which name the EJB will be bound to, it is recommended to specify a JNDI binding name using either of the suggested ways.

To inject a resource, specify a JNDI global binding name in jeus-ejb-dd.xml, jeus-web-dd.xml, and jeus-client-dd.xml, which are JEUS DD files. You can also map the resource to the value specified by mapped-name in ejb-jar.xml, web.xml or application-client.xml, or to the mappedName in the annotation. If nothing is specified, use a name according to the basic rules of JEUS.

In the actual development, it is recommended to use XML in specifying the JNDI global binding name, rather than using the mappedName of the annotation. If the application will be executed in many places, XML should be used since it needs to use a global name according to the environment. Injection is normally done for annotated setter methods and variables. However, it is possible to perform injection for non-annotated setter methods and variables, if they are specified by XML descriptor.

The following example shows how a client injects an EJB application using a mappedName of the annotation. Since statelessEJB1 application uses 'MyEJB1' as its JNDI global binding name, the client specifies the same name for mappedName of the @EJB annotation. If the client uses JNDI Lookup instead of Injection, it is possible to directly use the JNDI global binding name for lookup. If the client runs in a client container, it is possible to use the name, java:comp/env/ejb/sless1, from the application context using the application-client.xml file.

import ejb1.RemoteSession;

@Stateless(name="StatelessEJB1", mappedName="MyEJB1") 
public class StatelessEJB1 implements RemoteSession, LocalSession {...
}
...
@EJB(name="sless1", beanName="StatelessEJB1", mappedName="MyEJB1") 
private RemoteSession sless1;
...
RemoteSession session = context.lookup("MyEJB1");
...
// with client container and application-client.xml descriptor
RemoteSession session = context.lookup("java:comp/env/ejb/sless1");  

application class + / + the property name of the setter method or the variable

package test;

class Client {
    @Resource(name="jdbc/DB2") // default mapping if no mapped-name private
    javax.sql.DataSource myDataSource3;
    ...
}

You can use JEUS resources and applications through JEUS JNDI, without using an application container. To do so, execute a client program whose class path is set to the jclient.jar file in the JEUS_HOME\lib\client directory.

Because it is impossible to use dependency injection in this case, you need to modify the sources as shown in the following example. In the example, a binding name of the EJB application should follow JEUS's default name binding rule. The client can run on a client container. This means that all clients which do not use a client container can run on a client container.

package helloejb;

import java.io.*;
import javax.ejb.EJB;
import javax.naming.Context;
import javax.naming.InitialContext;
import java.util.Hashtable;

/**
 * HelloEJB application client
 */
public class HelloClient {
    private static Hello hello;
    
    public static void main(String[] args) {
        try {
            Hashtable env = new Hashtable();
            env.put(Context.INITIAL_CONTEXT_FACTORY,"jeus.jndi.JNSContextFactory");
            Context context = new InitialContext(env);
            hello = (Hello) context.lookup("helloejb.Hello");

            System.out.println("EJB output : " + hello.sayHello());
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

Client packaging is not performed in a client container that processes XML files. Thus, you need to create a JAR file without the standard or JEUS XML file. For deployment, copy the JAR file to any location. For execution, execute the previous client class just like executing a general Java class.

The result is as follows:

$ java -cp /jeus/lib/client/jclient.jar;./hello-client.jar helloejb.HelloClient
[2012.05.23 22:45:51][2] [t-1] [Network-0405] [Endpoint] exporting Endpoint (0:192.168.0.16:9756:-1:0x79F24F28)
[2012.05.23 22:45:51][2] [t-1] [Network-0002] [Acceptor] start to listen NonBlockingChannelAcceptor: /192.168.0.16:9756
EJB output : Hello EJB!

To use JEUS's Java EE services, a client has to provide its username and password to the client runtime in order to verify authorization for using the services. The services include EJB applications and JMS resources. The following are three ways to specify a username and password:

UserTransaction is used to utilize EJB client applications, JDBC DataSource, JMS connection factory and destination, and more as one global transaction or an XA transaction.

The transaction manager used by a client is either a server transaction manager or client transaction manager depending on whether it has direct control over resources.