1.13. JNDI naming

This section provides you the basic knowledge about JNDI naming.

Make sure you understand the Java Naming and Directory InterfaceTM (JNDI) concepts before using this service.

Prerequisites

We need to configure JNDI environment properties and Reference binding with the eXo container standard mechanism.

The Naming service covers:

Configuring the current Naming Context Factory implemented as an ExoContainer Component org.exoplatform.services.naming.InitialContextInitializer.
Binding Objects (References) to the current Context using org.exoplatform.services.naming.BindReferencePlugin component plugin.

How it works

JNDI System property initialization

After the start time, the Context Initializer (org.exoplatform.services.naming.InitialContextInitializer) traverses all initial parameters (that concern the Naming Context) configured in default-properties and mandatory-properties (see Configuration examples) then:

For default-properties: Check if this property is already set as a System property (System.getProperty(name)) and if not, set it. Using those properties is recommended with a third party Naming service provider.
For mandatory-properties: Set the property without checking.

Standard JNDI properties:

java.naming.factory.initial
java.naming.provider.url

and others (see JNDI docs)

JNDI reference binding

Another responsibility of Context Initializer org.exoplatform.services.naming.InitialContextInitializer is binding of preconfigured references to the naming context. For this purpose, it uses a standard eXo component plugin mechanism and in particular the org.exoplatform.services.naming.BindReferencePlugin component plugin. The configuration of this plugin includes three mandatory value parameters:

bind-name: the name of binding reference.
class-name: the type of binding reference.
factory: the object factory type.

And also ref-addresses property parameter with a set of references' properties (see Configuration examples). Context Initializer uses those parameters to bind the neccessary reference automatically.

Configuration examples

The InitialContextInitializer configuration example:


  <component>

    <type>org.exoplatform.services.naming.InitialContextInitializer</type>

    <init-params>

      <value-param>.

        <name>bindings-store-path</name>.

        <value>bind-references.xml</value>.

      </value-param>.

      <value-param> 

        <name>overload-context-factory</name> 

        <value>true</value> 

      </value-param>

      <properties-param>

        <name>default-properties</name>

        <description>Default initial context properties</description>

        <property name="java.naming.factory.initial" value="org.exoplatform.services.naming.SimpleContextFactory"/>

      </properties-param>

      <properties-param>

        <name>mandatory-properties</name>

        <description>Mandatory initial context properties</description>

        <property name="java.naming.provider.url" value="rmi://localhost:9999"/>

      </properties-param>

    </init-params>

  </component>

where:

binding-store-path is file path which stores binded datasources in runtime.

overload-context-factory allows to overload the default initial context factory by a context factory that is ExoContainer aware and that is able to delegate to the original initial context factory if it detects that it is not in the eXo scope. By default the feature is disabled since it is only required on AS that does not share the objects by default like Tomcat and it is not the case of JBoss AS.

The BindReferencePlugin component plugin configuration example (for JDBC datasource):


  <component-plugins> 

    <component-plugin> 

      <name>bind.datasource</name>

      <set-method>addPlugin</set-method>

      <type>org.exoplatform.services.naming.BindReferencePlugin</type>

      <init-params>

        <value-param>

          <name>bind-name</name>

          <value>jdbcjcr</value>

        </value-param>

        <value-param>

          <name>class-name</name>

          <value>javax.sql.DataSource</value>

        </value-param>  

        <value-param>

          <name>factory</name>

          <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>

        </value-param>

        <properties-param>

          <name>ref-addresses</name>

          <description>ref-addresses</description>

          <property name="driverClassName" value="org.hsqldb.jdbcDriver"/>

          <property name="url" value="jdbc:hsqldb:file:target/temp/data/portal"/>

          <property name="username" value="sa"/>

          <property name="password" value=""/>

        </properties-param>     

      </init-params>    

  </component-plugin>

Recommendations for application developers

SimpleContextFactory is created for testing purposes only, do not use it for production.
In J2EE environment, use Naming Factory objects provided with the Application Server.