~~Title: Addressing the Server via JNDI~~

The server for JVx clients is instantiated either at the current JVM or at the application server (e.g., Tomcat, JBoss). In the current VM, the call

<file java>
Server server = new Server();
</file>

is sufficient to create a server instance. However, this creates that risk that multiple server instances are created (which may well be desirable). The following method is available to treat the server as a singleton:

<file java>
Server server = Server.getInstance();
</file>

In doing so, we additionally attempt to address a server instance via JNDI.

A new instance of the server is created at the application server using ServletServer. This is accomplished by the following call:

<file java>
Server server = Server.getInstance();
</file>

If the server is available as a JNDI resource, the application server handles the instantiation of the server. This way one server instance could be used for all applications of an application server.
\\ \\ 
A global JNDI resource for the application server Tomcat is configured as follows:

**conf/server.xml**:

<file xml server.xml>
<GlobalNamingResources>
  ...
  ...
  ...
  <Resource auth="Container" 
            factory="org.apache.naming.factory.BeanFactory" 
            name="globalserver" 
            type="com.sibvisions.rad.server.Server"/>
    
</GlobalNamingResources>

<DefaultContext>
  <ResourceLink name="jvx/server" 
                global="globalserver" 
                type="com.sibvisions.rad.server.Server" />
</DefaultContext>
</file>

The ResourceLink in the DefaultContext can also be defined in the META-INF/context.xml of the respective web application. This always depends on the configuration of the server or the web application. One possible example:

<file xml context.xml>
<?xml version="1.0" encoding="UTF-8"?>
<Context>
   <ResourceLink name="jvx/server" 
                 global="globalserver" 
                 type="com.sibvisions.rad.server.Server" />          
</Context>
</file>

To only make the server available for single web applications via JNDI, it should be configured as follows:

**META-INF/context.xml**:

<file xml context.xml>
<?xml version="1.0" encoding="UTF-8"?>

<Context>
  <Resource name="jvx/server" auth="Container"
            type="com.sibvisions.rad.server.Server"
            factory="org.apache.naming.factory.BeanFactory"/>
</Context>
</file>

We always recommend the configuration of the deployment descriptor, whether the server is provided for all applications or only for single web applications:

<file xml web.xml>
<web-app ...>
  ...
  ...
  ...
  <resource-ref>
   <description>Object factory for Server instances.</description>
   <res-ref-name>jvx/server</res-ref-name>
   <res-ref-type>com.sibvisions.rad.server.Server</res-ref-type>
   <res-auth>Container</res-auth>
  </resource-ref>

</web-app>
</file>

In the case of a global server, the deployment descriptor would not have to be adapted, although it is recommended to better manage the utilized resources.

\\ 
**<fs 20px>Note</fs>**

If the server is configured globally, we have to provide all of the application data -- such as the rad directory, .class files, etc. -- also globally since the applications class loader is not used!