EJB Programmer's Guide: Defining the Deployment Descriptor

Target Audience and Content

The target audience for this guide is the Enterprise Bean provider, i.e. the person in charge of developing the software components on the server side. It describes how the bean provider should build the deployment descriptors of its components.

The content of this guide is the following:

Target Audience and Content
Principles
Example of Session Descriptors
Example of Container-managed Persistence Entity Descriptors (CMP1.1)
Tips

Principles

The bean programmer is responsible for providing the deployment descriptor associated with the developed Enterprise Beans. The Bean Provider's responsibilities and the Application Assembler's responsibilities is to provide an XML deployment descriptor that conforms to the deployment descriptor's XML DTD as defined in the EBJ specification version 2.0. (Refer to $JONAS_ROOT/xml/ejb-jar_2_0.dtd).

To deploy Enterprise JavaBeans on the EJB server, information not defined in the standard XML deployment descriptor may be needed. For example, this information may include the mapping of the bean to the underlying database for an entity bean with container-managed persistence. This information is specified during the deployment step in another XML deployment descriptor that is specific to JOnAS. The JOnAS-specific deployment descriptor's XML DTD is located in $JONAS_ROOT/xml/jonas-ejb-jar_X_Y.dtd. The file name of the JOnAS-specific XML deployment descriptor must be the file name of the standard XML deployment descriptor prefixed by 'jonas-'.

JOnAS interprets the <!DOCTYPE> tag at the parsing of the deployment descriptor XML files.
The parser first tries to get the specified DTD via the classpath, then it uses the specified URL (or path).

In the following two examples, the parser gets the jonas-ejb-jar_2_4.dtd DTD file in the JOnAS jar file.

    <!DOCTYPE jonas-ejb-jar PUBLIC "-//ObjectWeb//DTD JOnAS 2.4//EN" 
                                   "http://www.objectweb.org/jonas/dtds/jonas-ejb-jar_2_4.dtd">
    <!DOCTYPE jonas-ejb-jar SYSTEM "/usr/local/jonas/xml/jonas-ejb-jar_2_4.dtd">

The standard deployment descriptor should contain structural information for each enterprise bean that includes the following:

the Enterprise bean's name,
the Enterprise bean's class,
the Enterprise bean's home interface,
the Enterprise bean's remote interface,
the Enterprise bean's type,
a re-entrancy indication for the entity bean,
the session bean's state management type,
the session bean's transaction demarcation type,
the entity bean's persistence management,
the entity bean's primary key class,
container-managed fields,
environment entries,
the bean's EJB references,
resource manager connection factory references,
transaction attributes.

The JOnAS-specific deployment descriptor contains information for each enterprise bean including:

the JNDI name of the Home object that implement the Home interface of the enterprise bean,
the JNDI name of the DataSource object corresponding to the resource manager connection factory referenced in the enterprise bean's class,
the JNDI name of each EJB references,
the JNDI name of JMS administered objects,
information for the mapping of the bean to the underlying database, if it is an entity with container-managed persistence.

Example of Session Descriptors

<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN" 
                         "http://java.sun.com/dtd/ejb-jar_2_0.dtd">
<ejb-jar>
  <description>Here is the description of the test's beans</description>
  <enterprise-beans>
    <session>
      <description>... Bean example one ...</description>
      <display-name>Bean example one</display-name>
      <ejb-name>ExampleOne</ejb-name>
      <home>tests.Ex1Home</home>
      <remote>tests.Ex1</remote>
      <ejb-class>tests.Ex1Bean</ejb-class>
      <session-type>Stateful</session-type>
      <transaction-type>Container</transaction-type>
      <env-entry>
        <env-entry-name>name1</env-entry-name>
        <env-entry-type>java.lang.String</env-entry-type>
        <env-entry-value>value1</env-entry-value>
      </env-entry>
      <ejb-ref>
        <ejb-ref-name>ejb/ses1</ejb-ref-name>
        <ejb-ref-type>session</ejb-ref-type>
        <home>tests.SS1Home</home>
        <remote>tests.SS1</remote>
      </ejb-ref>
      <resource-ref>
        <res-ref-name>jdbc/mydb</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Application</res-auth>
      </resource-ref>
    </session>
  </enterprise-beans>
  <assembly-descriptor>
    <container-transaction>
      <method>
        <ejb-name>ExampleOne</ejb-name>
        <method-name>*</method-name>
      </method>
      <trans-attribute>Required</trans-attribute>
    </container-transaction>
    <container-transaction>
      <method>
        <ejb-name>ExampleOne</ejb-name>
        <method-inter>Home</ejb-name>
        <method-name>*</method-name>
      </method>
      <trans-attribute>Supports</trans-attribute>
    </container-transaction>
    <container-transaction>
      <method>
        <ejb-name>ExampleOne</ejb-name>
        <method-name>methodOne</method-name>
      </method>
      <trans-attribute>NotSupported</trans-attribute>
    </container-transaction>
    <container-transaction>
      <method>
        <ejb-name>ExampleOne</ejb-name>
        <method-name>methodTwo</method-name>
        <method-params><method-param>int</method-param></method-params>
      </method>
      <trans-attribute>Mandatory</trans-attribute>
    </container-transaction>
    <container-transaction>
      <method>
        <ejb-name>ExampleOne</ejb-name>
        <method-name>methodTwo</method-name>
        <method-params><method-param>java.lang.String</method-param></method-params>
      </method>
      <trans-attribute>NotSupported</trans-attribute>
    </container-transaction>
  </assembly-descriptor>
</ejb-jar>


<!DOCTYPE jonas-ejb-jar PUBLIC "-//ObjectWeb//DTD JOnAS 2.4//EN" 
                               "http://www.objectweb.org/jonas/dtds/jonas-ejb-jar_2_4.dtd">
<jonas-ejb-jar>
  <jonas-session>
    <ejb-name>ExampleOne</ejb-name>
    <jndi-name>ExampleOneHome</jndi-name>
    <jonas-ejb-ref>
      <ejb-ref-name>ejb/ses1</ejb-ref-name>
      <jndi-name>SS1Home_one</jndi-name>
    </jonas-ejb-ref>
    <jonas-resource>
      <res-ref-name>jdbc/mydb</res-ref-name>
      <jndi-name>jdbc_1</jndi-name>
    </jonas-resource>
  </jonas-session>
</jonas-ejb-jar>

Example of Container-managed Persistence Entity Descriptors (CMP 1.1)

<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN" 
                         "http://java.sun.com/dtd/ejb-jar_2_0.dtd">
<ejb-jar>
  <description>Here is the description of the test's beans</description>
  <enterprise-beans>
    <entity>
      <description>... Bean example one ...</description>
      <display-name>Bean example two</display-name>
      <ejb-name>ExampleTwo</ejb-name>
      <home>tests.Ex2Home</home>
      <remote>tests.Ex2</remote>
      <local-home>tests.Ex2LocalHome</local-home>
      <local>tests.Ex2Local</local>
      <ejb-class>tests.Ex2Bean</ejb-class>
      <persistence-type>Container</persistence-type>
      <prim-key-class>tests.Ex2PK</prim-key-class>
      <reentrant>False</reentrant>
      <cmp-version>1.x</cmp-version>
      <cmp-field>
        <field-name>field1</field-name>
      </cmp-field>
      <cmp-field>
        <field-name>field2</field-name>
      </cmp-field>
      <cmp-field>
        <field-name>field3</field-name>
      </cmp-field>
      <primkey-field>field3</primkey-field>
      <env-entry>
        <env-entry-name>name1</env-entry-name>
        <env-entry-type>java.lang.String</env-entry-type>
        <env-entry-value>value1</env-entry-value>
      </env-entry>
    </entity>
  </enterprise-beans>
  <assembly-descriptor>
    <container-transaction>
      <method>
        <ejb-name>ExampleTwo</ejb-name>
        <method-name>*</method-name>
      </method>
      <trans-attribute>Supports</trans-attribute>
    </container-transaction>
  </assembly-descriptor>
</ejb-jar>


<!DOCTYPE jonas-ejb-jar PUBLIC "-//ObjectWeb//DTD JOnAS 2.4//EN" 
                               "http://www.objectweb.org/jonas/dtds/jonas-ejb-jar_2_4.dtd">
<jonas-ejb-jar>
  <jonas-entity>
    <ejb-name>ExampleTwo</ejb-name>
    <jndi-name>ExampleTwoHome</jndi-name>
    <jndi-local-name>ExampleTwoLocalHome</jndi-local-name>
    <jdbc-mapping>
      <jndi-name>jdbc_1</jndi-name>
      <jdbc-table-name>YourTable</jdbc-table-name>
      <cmp-field-jdbc-mapping>
        <field-name>field1</field-name>
        <jdbc-field-name>dbf1</jdbc-field-name>
      </cmp-field-jdbc-mapping>
      <cmp-field-jdbc-mapping>
        <field-name>field2</field-name>
        <jdbc-field-name>dbf2</jdbc-field-name>
      </cmp-field-jdbc-mapping>
      <cmp-field-jdbc-mapping>
        <field-name>field3</field-name>
        <jdbc-field-name>dbf3</jdbc-field-name>
      </cmp-field-jdbc-mapping>
      <finder-method-jdbc-mapping>
        <jonas-method>
          <method-name>findByField1</method-name>
        </jonas-method>
        <jdbc-where-clause>where dbf1 = ?</jdbc-where-clause>
      </finder-method-jdbc-mapping>
    </jdbc-mapping>
  </jonas-entity>
</jonas-ejb-jar>

Tips

Although some characters, such as ">", are legal, it is good practice to replace them with XML entity references.

The following is a list of the predefined entity references for XML:

<	<	less than
>	>	greater than
&	&	ampersand
'	'	apostrophe
"	"	quotation mark