You use the tnameserv command as a substitute for Object Request Broker Daemon (ORBD).
Synopsis
tnameserve -ORBInitialPort [ nameserverport ]
Description
Java Interface Definition Language (IDL) includes the Object Request Broker Daemon (ORBD). ORBD is a daemon process that contains a Bootstrap Service, a Transient Naming Service, a Persistent Naming Service, and a Server Manager. The Java IDL tutorials all use ORBD, but you can substitute the tnameserv command for the orbd command in any of the examples that use a Transient Naming Service.
The CORBA Common Object Services (COS) Naming Service provides a tree-structure directory for object references similar to a file system that provides a directory structure for files. The Transient Naming Service provided with Java IDL, tnameserv, is a simple implementation of the COS Naming Service specification.
Object references are stored in the name space by name and each object reference-name pair is called a name binding. Name bindings can be organized under naming contexts. Naming contexts are name bindings and serve the same organizational function as a file system subdirectory. All bindings are stored under the initial naming context. The initial naming context is the only persistent binding in the name space. The rest of the name space is lost when the Java IDL naming service process stops and restarts.
For an applet or application to use COS naming, its ORBD must know the port of a host running a naming service or have access to an initial naming context string for that naming service. The naming service can be either the Java IDL naming service or another COS-compliant naming service.
Start the Naming Service
You must start the Java IDL naming service before an application or applet that uses its naming service. Installation of the Java IDL product creates a script (Oracle Solaris, Linux, and OS X: tnameserv) or executable file (Windows: tnameserv.exe) that starts the Java IDL naming service. Start the naming service so that it runs in the background.
If you specify otherwise, then the Java IDL naming service listens on port 900 for the bootstrap protocol used to implement the Object Request Broker (ORB) resolve_initial_references and list_initial_references methods, as follows:
tnameserv -ORBInitialPort nameserverport&
If you don’t specify the name server port, then port 900 is used by default. When running Oracle Solaris software, you must become the root user to start a process on a port below 1024. For this reason, it’s recommended that you use a port number greater than or equal to 1024. To specify a different port, for example, 1050, and to run the naming service in the background, from an Oracle Solaris, Linux, or OS X command shell, enter:
tnameserv -ORBInitialPort 1050&
From an MS-DOS system prompt (Windows), enter:
start tnameserv -ORBInitialPort 1050
Clients of the name server must be made aware of the new port number. Do this by setting the org.omg.CORBA.ORBInitialPort property to the new port number when you create the ORB object.
Run the Server and Client on Different Hosts
In most of the Java IDL and RMI-IIOP tutorials, the naming service, server, and client are all running on the development machine. In real-world deployment, the client and server probably run on different host machines from the Naming Service.
For the client and server to find the Naming Service, they must be made aware of the port number and host on which the naming service is running. Do this by setting the org.omg.CORBA.ORBInitialPort and org.omg.CORBA.ORBInitialHost properties in the client and server files to the machine name and port number on which the Naming Service is running.
You could also use the command-line options -ORBInitialPort nameserverport# and -ORBInitialHost nameserverhostname to tell the client and server where to find the naming service.
For example, suppose the Transient Naming Service, tnameserv is running on port 1050 on host nameserverhost. The client is running on host clienthost, and the server is running on host serverhost.
Start tnameserv on the host nameserverhost:
tnameserv -ORBInitialPort 1050
Start the server on the serverhost:
java Server -ORBInitialPort 1050 -ORBInitialHost nameserverhost
Start the client on the clienthost:
java Client -ORBInitialPort 1050 -ORBInitialHost nameserverhost
Stop the Naming Service
To stop the Java IDL naming service, use the relevant operating system command, such as kill for an Oracle Solaris, Linux, or OS X process or Ctrl+C for a Windows process. The naming service continues to wait for invocations until it’s explicitly shut down. Note that names registered with the Java IDL naming service disappear when the service is terminated.
Options
-JoptionPasses option to the JVM, where option is one of the options described on the reference page for the Java application launcher. For example, -J-Xms48m sets the startup memory to 48 MB. See Overview of Java Options.
Example of Adding Objects to the Name Space
This example shows how to add names to the following simple tree:
Initial Naming Context
plans
Personal
calendar
schedule
In the tree, plans is an object reference and Personal is a naming context that contains two object references: calendar and schedule.
The following sample program is a self-contained Transient Naming Service client that creates the tree:
import java.util.Properties;
import org.omg.CORBA.*;
import org.omg.CosNaming.*;
public class NameClient {
public static void main(String args[]) {
try {
In Start the Naming Service, the nameserver was started on port 1050. The following code example ensures that the client program is aware of this port number.
Properties props = new Properties();
props.put("org.omg.CORBA.ORBInitialPort", "1050");
ORB orb = ORB.init(args, props);
The following code example obtains the initial naming context and assigns it to ctx. The second line copies ctx into a dummy object reference objref that is attached to various names and added into the name space.
NamingContext ctx =
NamingContextHelper.narrow(
orb.resolve_initial_references("NameService"));
NamingContext objref = ctx;
The following code example creates a name plans of type text and binds it to the dummy object reference. The plans is then added under the initial naming context using the rebind method. The rebind method enables you to run this program over and over again without getting the exceptions from using the bind method.
NameComponent nc1 = new NameComponent("plans", "text");
NameComponent[] name1 = {nc1};
ctx.rebind(name1, objref);
System.out.println("plans rebind successful!");
The following code example creates a naming context called Personal of type directory. The resulting object reference, ctx2, is bound to the name and added under the initial naming context.
NameComponent nc2 = new NameComponent("Personal", "directory");
NameComponent[] name2 = {nc2};
NamingContext ctx2 = ctx.bind_new_context(name2);
System.out.println("new naming context added..");
The remainder of the code binds the dummy object reference using the names schedule and calendar under the Personal naming context (ctx2).
NameComponent nc3 = new NameComponent("schedule", "text");
NameComponent[] name3 = {nc3};
ctx2.rebind(name3, objref);
System.out.println("schedule rebind successful!");
NameComponent nc4 = new NameComponent("calendar", "text");
NameComponent[] name4 = {nc4};
ctx2.rebind(name4, objref);
System.out.println("calendar rebind successful!");
} catch (Exception e) {
e.printStackTrace(System.err);
}
}
}
Example of Browsing the Name Space
The following sample program shows how to browse the name space:
import java.util.Properties;
import org.omg.CORBA.*;
import org.omg.CosNaming.*;
public class NameClientList {
public static void main(String args[]) {
try {
In Start the Naming Service, the nameserver was started on port 1050. The following code example ensures that the client program is aware of this port number:
Properties props = new Properties();
props.put("org.omg.CORBA.ORBInitialPort", "1050");
ORB orb = ORB.init(args, props);
The following code example obtains the initial naming context:
NamingContext nc =
NamingContextHelper.narrow(
orb.resolve_initial_references("NameService"));
The list method lists the bindings in the naming context. In this case, up to 1000 bindings from the initial naming context will be returned in the BindingListHolder; any remaining bindings are returned in the BindingIteratorHolder.
BindingListHolder bl = new BindingListHolder();
BindingIteratorHolder blIt= new BindingIteratorHolder();
nc.list(1000, bl, blIt);
The following code example gets the array of bindings out of the returned BindingListHolder. If there are no bindings, then the program ends.
Binding bindings[] = bl.value;
if (bindings.length == 0) return;
The remainder of the code loops through the bindings and prints the names.
for (int i=0; i < bindings.length; i++) {
// get the object reference for each binding
org.omg.CORBA.Object obj = nc.resolve(bindings[i].binding_name);
String objStr = orb.object_to_string(obj);
int lastIx = bindings[i].binding_name.length-1;
// check to see if this is a naming context
if (bindings[i].binding_type == BindingType.ncontext) {
System.out.println("Context: " +
bindings[i].binding_name[lastIx].id);
} else {
System.out.println("Object: " +
bindings[i].binding_name[lastIx].id);
}
}
} catch (Exception e) {
e.printStackTrace(System.err)
}
}
}