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This chapter provides you the basic knowledge about JNDI naming, such as, what it is, how it works and how it is used.
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.
Make sure you understand the Java Naming and Directory InterfaceTM (JNDI) concepts before using this service.
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)
and:
For default-properties: Check if this property
is already set as a System property
(System.getProperty(name)) and set this property if
it's not found. 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)
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.
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 don't share the objects by default like tomcat but unlike 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>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.
InitialContextInitalizer also provides feature of
references binding in runtime. References have bind in runtime will be
persisted and automatically rebinded on a next system start.
Service provides methods for binding reference.
public void bind(String bindName,
String className,
String factory,
String factoryLocation,
Map<String, String> refAddr)
throws NamingException, FileNotFoundException, XMLStreamException;bindName: name of binding.
className: the fully-qualified name of the class
of the object to which this Reference refers.
factory: the name of the factory class for
creating an instance of the object to which this Reference
refers.
factoryLocation: the location of the factory
class.
refAddr: object's properties map.
Example of usage:
// obtain InitialContextInitializer instance from ExoContainer (e.g. PortalContainer)
InitialContextInitializer initContext = (InitialContextInitializer)container.getComponentInstanceOfType(InitialContextInitializer.class);
Map<String, String> refAddr = new HashMap<String, String>();
refAddr.put("driverClassName", "oracle.jdbc.OracleDriver");
refAddr.put("url", "jdbc:oracle:thin:@oraclehost:1521:orcl");
refAddr.put("username", "exouser");
refAddr.put("password", "exopassword");
initContext.bind("jdbcexco", "javax.sql.DataSource", "org.apache.commons.dbcp.BasicDataSourceFactory", null, refAddr);
// try to get just bound DataSource
DataSource ds = (DataSource)new InitialContext().lookup("jdbcexo");