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tnameserv - Java IDL name server starter script
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 name server process halts and restarts.
For an applet or application to use COS naming, its ORB must know the name and port of a host running a naming service or have access to a stringified initial naming context for that name server. The naming service can either be the Java IDL name server or another COS-compliant name service.
If you do not specify otherwise, the Java IDL name server listens on port 900 for the bootstrap protocol used to implement the ORB resolve_initial_references() and list_initial_references() methods. Specify a different port, for example, 1050, as follows:
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.
Initial
Naming Context
/ \
/ \
plans personal
/\
/ \
calendar schedule
In this example, "plans"
is an object reference and
"personal"
is a naming context that contains 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 Name Server,
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 and assigns it to
ctx.
The second line copies
ctx
into a dummy object reference,
objref,
that we will attach to various names and add into the namespace.
NamingContext ctx = NamingContextHelper.narrow
(orb.resolve_initial_references("NameService"));
NamingContext objref = ctx;
The following code creates a
name "plans" of type "text" and binds it to our dummy
object reference.
"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 would get from using
bind.
NameComponent nc1 = new NameComponent("plans", "text");
NameComponent[] name1 = {nc1};
ctx.rebind(name1, objref);
System.out.println("plans rebind sucessful!");
The following 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 sucessful!");
NameComponent nc4 = new NameComponent("calender", "text");
NameComponent[] name4 = {nc4};
ctx2.rebind(name4, objref);
System.out.println("calender rebind sucessful!");
} catch (Exception e) {
e.printStackTrace(System.err);
}
}
}
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 Name Server,
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 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 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);
}
}
}
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