This section discusses EJB types and their DD configurations.

EJB Types

The following EJB types are supported in JEUS.

This chapter describes characteristics and configurations common to all bean types. In the previous list, you can find reference to additional information about each type.

Deployment Descriptor Configuration by EJB 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 more information about JEUS EJB DD, refer to "제3장 EJB Modules".

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

The previous table is partitioned as follows:

All the EJB settings are configured in the jeus-ejb-dd.xml file, the JEUS EJB DD file. The parent XML tag is <jeus-bean> for all bean types.

The next section will describe settings applicable to XML parent tags for the five EJB types. Other tags outside the <beanlist> have already been discussed in "제3장 EJB Modules". For more information about specific XML parent tags (bean type), refer to the next chapters in this guide.

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>

4.2.2. Configuring Thread Tickets

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

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

[Figure 4.1] TTP State Chart

As you can see in 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 ten minutes, it throws a RemoteException due to a timeout.

TTs are returned to TTP when the client gets disconnected after an 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. A bean pool, instead of a TTP, should be configured for an MDB.

Note

For more information about connection and bean pools, refer to "Chapter 7. Session Beans" and "Chapter 8. Entity Beans". For more information about using bean pool in MDBs, refer to "Chapter 9. Message Driven Beans (MDBs)".

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 ten minutes, it throws a RemoteException due to a timeout.

The following shows how to configure a BMP bean as above.

[Example 4.3] Configuring a BMP Bean: <<jeus-ejb-dd.xml>>

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

@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>

<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>

<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="3.2" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
              http://xmlns.jcp.org/xml/ns/javaee/ejb-jar_3_2.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>

JEUS does not provide a method to control each EJB included in the EJB module. However, you can monitor each bean with the jeusadmin or WebAdmin. It is recommended to use the WebAdmin.

In the console tool, each EJB information including bean name, export name, and status can be displayed using the application-info command. In the following example, we assume that an EJB called countermod is deployed.

As the result of the previous command, the name and export name of each bean registered to the EJB module are displayed.

[DAS]domain1.adminServer>application-info -server server1 -id countermod -detail
General information about the EJB module [countermod].
==============================================================
+-------------+----------------------------------------------+
| Module Name |              Unique Module Name              |
+-------------+----------------------------------------------+
| countermod  | countermod                                   |
+-------------+----------------------------------------------+
==============================================================

Beans
================================================================================

+-----------+-------------------------+-------------------+--------------------+
| Bean Name |           Type          | Local Export Name | Remote Export Name |
+-----------+-------------------------+-------------------+--------------------+
| Count     | StatelessSessionBean    |                   | Count              |
+-----------+-------------------------+-------------------+--------------------+

================================================================================

The status of each bean in EJB module can be monitored with the following command.

[DAS]domain1.adminServer>application-info -server server1 -id countermod -bean Count
Module name : countermod
Bean name : Count
================================================================================

+---------------+-----------+-------------------+--------------+---------------+
|      Name     |  (Count)  | WaterMark(High:Low| Bound(Upper:L| Time(Max:Min:T|
|               |           |       :Cur)       |    ower)     |     otal)     |
+---------------+-----------+-------------------+--------------+---------------+
| create        | times(0)  |                   |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| comitted      | transactio|                   |              |               |
|               |n(0)       |                   |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| total-remote-t|           |thread(100:100:100)|              |               |
|hread          |           |                   |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| timed-rb      | transactio|                   |              |               |
|               |n(0)       |                   |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| remove        | times(0)  |                   |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| active-bean   |           | bean(0:0:0)       |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| request       | request(0)|                   |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| total-bean    |           | bean(0:0:0)       |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| rolledback    | transactio|                   |              |               |
|               |n(0)       |                   |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| active-thread |           | thread(0:0:0)     |              |               |
+---------------+-----------+-------------------+--------------+---------------+
| MethodReadyCou|           | bean(0:0:0)       |              |               |
|nt             |           |                   |              |               |
+---------------+-----------+-------------------+--------------+---------------+

================================================================================

There are some settings that can be uniformly applied to all EJB types in order to enhance EJB operation performance (or to prevent system resources from being wasted):

There are many tuning tips for each bean type besides the already mentioned basic optimization options. Therefore, look up the corresponding chapter for optimization and tuning method recommended for each EJB type.