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tnameserv(1) - phpMan
tnameserv(1) General Commands Manual tnameserv(1)
Name
Java IDL: Transient Naming Service - tnameserv
This document discusses using the Java IDL Transient Naming Service, tnameserv. Java IDL
also includes the Object Request Broker Daemon (ORBD). ORBD is a daemon process containing
a Bootstrap Service, a Transient Naming Service, a Persistent Naming Service, and a Server
Manager. The Java IDL tutorials all use ORBD, however, you can substitute tnameserv for
orbd in any of the examples that use a Transient Naming Service. For documentation on the
orbd tool, link to its orbd(1) or the Java IDL Naming Service Included with ORBD @
http://docs.oracle.com/javase/7/docs/technotes/guides/idl/jidlNaming.html topic.
Topics in this section include:
o Java IDL Transient Naming Service
o Starting the Java IDL Transient Naming Service
o Stopping the Java IDL Transient Naming Service
o Sample Client: Adding Objects to the Namespace
o Sample Client: Browsing the Namespace
Java IDL Transient Naming Service
The CORBA COS (Common Object Services) Naming Service provides a tree-like directory for
object references much like a filesystem 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 namespace by name and each object reference-name pair
is called a name binding. Name bindings may be organized under naming contexts. Naming
contexts are themselves 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 namespace; the rest of the namespace
is lost if the Java IDL naming service process halts and restarts.
For an applet or application to use COS naming, its ORB must know the port of a host run‐
ning a naming service or have access to a stringified initial naming context for that nam‐
ing service. The naming service can either be the Java IDL naming service or another
COS-compliant naming service.
Starting the Java IDL Transient 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 (Solaris: tnameserv)
or executable file (Windows NT: tnameserv.exe) that starts the Java IDL naming service.
Start the naming service so it runs in the background.
If you do not specify otherwise, the Java IDL naming service listens on port 900 for the
bootstrap protocol used to implement the ORB resolve_initial_references() and list_ini‐
tial_references() methods, as follows:
tnameserv -ORBInitialPort nameserverport&
If you do not specify the name server port, port 900 is used by default. When running
Solaris software, you must become root to start a process on a port under 1024. For this
reason, we recommend 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
a UNIX 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 creating the ORB
object.
Running 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, it is likely that the
client and server will run on different host machines than 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.
An example of this is shown in The Hello World Example Using RMI-IIOP @
http://docs.oracle.com/javase/7/docs/technotes/guides/rmi-iiop/rmiiiopexample.html. You
could also use the command line options -ORBInitialPort nameserverport# and -ORBInitial‐
Host nameserverhostname to tell the client and server where to find the Naming Service.
Java IDL: Running the Hello World Example on TWO Machines @
http://docs.oracle.com/javase/7/docs/technotes/guides/idl/tutorial/jidl2machines.html
shows one way of doing this using the command line option.
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.
o Start tnameserv on the host nameserverhost, as follows:
tnameserv -ORBInitialPort 1050
o Start the server on the serverhost, as follows:
java Server -ORBInitialPort 1050 -ORBInitialHost nameserverhost
o Start the client on the clienthost, as follows:
java Client -ORBInitialPort 1050 -ORBInitialHost nameserverhost
The -J option
This command-line option is available for use with tnameserve:
-Joption
Pass option to the Java virtual machine, where option is one of the options
described on the reference page for java(1). For example, -J-Xms48m sets the startup
memory to 48 megabytes. It is a common convention for -J to pass options to the
underlying virtual machine.
Stopping the Java IDL Transient Naming Service
To stop the Java IDL naming service, use the relevant operating system command, such as
kill for a Unix process, or Ctrl-C for a Windows process. The naming service will continue
to wait for invocations until it is explicitly shutdown. Note that names registered with
the Java IDL naming service disappear when the service is terminated.
Sample Client: Adding Objects to the Namespace
The following sample program illustrates how to add names to the namespace. It is a
self-contained Transient Naming Service client that creates the following simple tree.
o Initial Naming Context
* plans
* Personal
- calendar
- schedule
In this example, plans is an object reference and Personal is a naming context that con‐
tains two object references: calendar and schedule.
import java.util.Properties;
import org.omg.CORBA.*;
import org.omg.CosNaming.*;
public class NameClient
{
public static void main(String args[])
{
try {
In the above section, Starting the Java IDL Transient Naming Service, the nameserver was
started on port 1050. The following code 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);
This code obtains the initial naming context and assigns it to ctx. The second line copies
ctx into a dummy object reference objref that we'll attach to various names and add into
the namespace.
NamingContext ctx =
NamingContextHelper.narrow(orb.resolve_initial_references("NameService"));
NamingContext objref = ctx;
This code creates a name "plans" of type "text" and binds it to our dummy object refer‐
ence. "plans" is then added under the initial naming context using rebind. The rebind
method allows us to run this program over and over again without getting the exceptions
we'd get from using bind.
NameComponent nc1 = new NameComponent("plans", "text");
NameComponent[] name1 = {nc1};
ctx.rebind(name1, objref);
System.out.println("plans rebind successful!");
This code 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("calender", "text");
NameComponent[] name4 = {nc4};
ctx2.rebind(name4, objref);
System.out.println("calender rebind successful!");
} catch (Exception e) {
e.printStackTrace(System.err);
}
}
}
Sample Client: Browsing the Namespace
The following sample program illustrates how to browse the namespace.
import java.util.Properties;
import org.omg.CORBA.*;
import org.omg.CosNaming.*;
public class NameClientList
{
public static void main(String args[])
{
try {
In the above section, Starting the Java IDL Transient Naming Service, the nameserver was
started on port 1050. The following code 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 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 bind‐
ings 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);
This code gets the array of bindings out of the returned BindingListHolder. If there are
no bindings, 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 out.
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);
}
}
}
16 Mar 2012 tnameserv(1)
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