The following EJB types are supported in JEUS.

This chapter will describe all the shared characteristics and configurations that apply to all bean types. In the previous list, we have indicated the chapter where you can find additional information about the type.

JEUS EJB Deployment Descriptor (hereafter JEUS EJB DD) is a generic XML file named jeus-ejb-dd.xml, and it is placed in the META-INF directory of an EJB JAR file. For information on JEUS EJB DD, refer to "Chapter 3. EJB Module".

The following table offers a summary of all the functions and components that can be configured in JEUS EJB DD ("@" indicates that the entity can be configured using annotation). The items listed on the left column of the table represent the actual configurable XML tags of a JEUS EJB DD. The six columns to the right show whether the component is applicable to each of the EJB types.

The previous table is partitioned as follows:

The following settings are only for JEUS, and are defined in the jeus-ejb-dd.xml file. For more information on this file, refer to "Chapter 3. EJB Module".

The following examples show how the previous settings can be applied to the Session Bean classes and DDs. Elements of corresponding annotation and DDs are displayed in bold.

package ejb.basic.statefulSession;

@Stateful(name="counter", mappedName="counterEJB")
public class CounterEJB implements Counter, CounterLocal
{
   private int count = 0;

   public void increase()
   {
      count++;
   }
 ...
}

<jeus-ejb-dd>
    . . .
    <beanlist>
        <jeus-bean>
            <ejb-name>counter</ejb-name>
            <export-name>counterEJB</export-name>
            <local-export-name>counterEJB_Local</local-export-name>
            <export-port>7654</export-port>
            <export-iiop/>
             . . .
        </jeus-bean>
        . . .
    </beanlist>
    . . .
</jeus-ejb-dd>

The following figure illustrates the concept of EJB thread ticket pool (hereafter TTP).

If there is a client request, a new RMI thread is assigned to the client request. If the number of assigned threads is greater than the configured maximum value, the request waits for an available thread.

[Figure 4.1] TTP State Chart

As can be seen from the figure, a thread pool contains thread tickets (hereafter TT). One TT permits one client thread to access the EJB engine. When a client request arrives, one TT is drawn from the TP and assigned to the client. This implies that each client thread will be assigned to one EJB object that will relay the request to an actual EJB instance. An EJB object is thus an object that lives in the EJB engine and manages the connection between an EJB client and an actual EJB instance.

If more client requests arrive than there are TTs in the thread ticket pool, the new requests must wait until a TT is returned to the pool. If the waiting period exceeds 10 minutes, it throws a RemoteException due to a timeout.

TTs are returned to TTP when the client gets disconnected after EJB process terminates (for stateless session bean), or a connection timeout occurs. Each remote-call enabled EJB component contains a TTP. There are also connection and bean pools. Bean pool, instead of TTP, should be configured for MDB.

TT of EJB is configured in the <thread-max> element of the root XML tag of the bean. This value represents the maximum number of allowable threads that can operate in each EJB, in other words, the maximum number of TT. The default value is 100. If the number of client requests in a queue is larger than this value, new requests have to wait until a running job is finished and the TT is returned to the pool. If the waiting period exceeds 10 minutes, it throws a RemoteException due to a timeout.

The following shows how to apply the previous settings to a BMP bean.

<jeus-ejb-dd>
    . . .
    <beanlist>
        <jeus-bean>
            . . .
            <thread-max>200</thread-max>
            . . .
        </jeus-bean>
        . . .
    </beanlist>
    . . .
</jeus-ejb-dd>

External references that the bean uses can be configured through annotation or JNDI export name in jeus-ejb-dd.xml, which is mapped to the reference name used in ejb-jar.xml. In the actual system, all defined external references must be mapped to JNDI export name.

Annotations or all the external references defined in ejb-jar.xml must be mapped to relevant tags in jeus-ejb-dd.xml using the JNDI export-name used in the actual system.

Reference tags of ejb-jar.xml and JEUS EJB DD files are as follows:

Every <env> tag has the following child tags:

Other three tags (<ejb-ref>, <res-ref>, and <res-env-ref>) have several <jndi-info> child tags. These tags, in turn, have to set the following child tags to map JNDI export name to reference.

The following is an example of annotation and XML that illustrates how to map external references to JNDI.

@Stateful

@EJB(name="AccountEJB", beanInterface=ejb.Account.class, mapppedName="ACCEJB")
@Resource(name="jdbc/DBDS", type=javax.sql.DataSource.class, mappedName="ACCOUNTDB")
public class CounterEJB implements Counter{
    @Resource(name="minAmount")
    private int minAccount = 100;

 . . .
}

<ejb-jar.xml>
    . . .
    <enterprise-beans>
        <session>
            . . .
            <env-entry>
                <env-entry-name>minAmount</env-entry-name>
                <env-entry-type>java.lang.Integer</env-entry-type>
            </env-entry>
            <ejb-ref>
                <ejb-ref-name>AccountEJB</ejb-ref-name>    
                <ejb-ref-type>Session<ejb-ref-type>
                <remote>ejb.Account</remote>
            </ejb-ref>
            <resource-ref>
                <res-ref-name>jdbc/DBDS</res-ref-name>
                <res-ref-type>javax.sql.DataSource</res-ref-type>
            </resource-ref>
            . . .
        </session>
    </enterprise-beans>
    . . .
</ejb-jar.xml>

<jeus-ejb-dd>
    . . .
    <beanlist>
        <jeus-bean>
            . . .
            <env>
                <name>minAmount</name>
                <type>java.lang.Integer</type>
                <value>100</value>
            </env>
            <ejb-ref>
                <jndi-info>
                    <ref-name>AccountEJB</ref-name>
                    <export-name>ACCEJB</export-name>
                </jndi-info>
            </ejb-ref>
            <res-ref>
                <jndi-info>
                    <ref-name>jdbc/DBDS</ref-name>
                    <export-name>ACCOUNTDB</export-name>
                </jndi-info>
            </res-ref>
            . . .
        </jeus-bean>
        . . .
    </beanlist>
    . . .
</jeus-ejb-dd>

In order to set up HTTP invocation on a specific EJB module, <invoke-http> needs to be configured inside the <jeus-bean> element of jeus-ejb-dd.xml. If an EJB engine needs HTTP invocation, add the <invoke-http> tag to the ejb-engine in the jeus-ejb-dd.xml file. (mentioned in "Chapter 2. EJB Engine"). Settings in the domain.xml file will be applied to all the modules, but if the DD of each module contains the <invoke-http> setting, the setting in DD file is used.

The following example configures the HTTP invoke environment properties in jeus-ejb-dd.xml.

<jeus-ejb-dd>
    . . .
    <beanlist>
        <jeus-bean>
            . . .
            <invoke-http>
                <url>
                    /mycontext/RMIServletHandler
                </url>
                <http-port>
                    80
                </http-port>
            </invoke-http>
            . . .
        </jeus-bean>
    </beanlist>
    . . .
</jeus-ejb-dd>

<invoke-http> tag has the following two child tags.

JEUS provides JEUS RMI communication that helps improve its performance. This RMI is useful especially when there are many clients, because it can also use Non-blocking IO to communicate. In order to use JEUS RMI, you only need to configure JEUS_HOME/lib/client/jclient.jar, the client library file, to the classpath.

Specify whether to use JEUS RMI in the jeus-ejb-dd.xml file of each bean, or use the system property (-Djeus.ejb.rmi.jeus=true) for the entire JEUS system. DD configuration has higher priority than the latter.

Communication layer details, such as whether to use Blocking IO or Non-blocking IO and whether to use channel or socket for JEUS RMI, can be configured through the system property. For more information, refer to "JEUS Reference Book".

This section describes how to configure security for EJB in JEUS. Here security refers to certification and authorization.

The following issues are covered by JEUS EJB security settings.

<jeus-ejb-dd>
    <module-info>
        <role-permission>
            <role>manager</role>
            <principal>peter</principal>
        </role-permission>
    </module-info>
    <beanlist>
       . . .
    </beanlist>
    . . .
</jeus-ejb-dd>

<jeus-ejb-dd>
    . . .
    <beanlist>
        <jeus-bean>
            . . .
            <run-as-identity>
                <principal-name>peter</principal-name>
            </run-as-identity>
            . . .
        </jeus-bean>
        . . .
    </beanlist>
    . . .
</jeus-ejb-dd>

@Stateless(name="CustomerEJB")
@RolesAllowed("CUSTOMER")
public class CustomerBean implementes Customer {
    ...
}

@Stateful(name="EmployeeService")
@RunAs("ADMIN")
public class EmployeeServiceBean implements EmployService{
    ...
}

<?xml version="1.0"?>
<ejb-jar version="3.1" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
        http://java.sun.com/xml/ns/javaee/ejb-jar_3_0.xsd">
    <enterprise-beans>
        <session>
            <ejb-name>CustomerEJB</ejb-name>
            . . .
            <security-role-ref>
                <role-name>CUSTOMER</role-name>
            </security-role-ref>
            <security-identity>
                <use-caller-identity />
            </security-identity>
        </session>
        <session>
            <ejb-name>EmployeeService</ejb-name>
            . . .
            <security-identity>
                <run-as>
                    <role-name>ADMIN</role-name>
                </run-as>
            </security-identity>
        </session>
        . . .
    </enterprise-beans>
    <assembly-descriptor>
       <security-role>
           <role-name>CUSTOMER</role-name>
       </security-role>
       <method-permission>
           <role-name>CUSTOMER</role-name>
           <method>
               <ejb-name>CustomerEJB</ejb-name>
               <method-name>*</method-name>
               <method-params />
           </method>
       </method-permission>
        . . .
    </assembly-descriptor>
    . . .
</ejb-jar>

<?xml version="1.0" encoding="UTF-8"?>
<jeus-ejb-dd xmlns="http://www.tmaxsoft.com/xml/ns/jeus">
    <module-info>
        . . .
        <role-permission>
            <principal>customer</principal>
            <role>CUSTOMER</role>
        </role-permission>
    </module-info>
    <beanlist>
        <jeus-bean>
            <ejb-name>EmployeeService</ejb-name>
            <run-as-identity>
                <principal-name>peter</principal-name>
            </run-as-identity>
        </jeus-bean>
        . . .
    </beanlist>
    . . .
</jeus-ejb-dd>

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<accounts xmlns="http://www.tmaxsoft.com/xml/ns/jeus">
    <users>
        <user>
            <name>customer</ name>
            <password>{SHA}blSUPYpdjb8QDcq+ozfbIEZx5oY=</name>
            <group>test</group>
        </user>
       <user>
            <name>peter</ name>
            <password>{SHA}McbQlyhI3yiOG1HGTg8DQVWkyhg=</name>
            <group>test</group>
        </user>
    </users>
</accounts>

The TTP should be configured correctly for an EJB to exhibit the best performance. You can apply the following principles for this.

TTP setting acts as a valve that controls the volume of accesses to a certain EJB.