JavaTM 2 Platform
Std. Ed. v1.3
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|BindingIterator||The BindingIterator interface allows a client to iterate through the bindings using the next_one or next_n operations.|
|BindingIteratorOperations||org/omg/CosNaming/BindingIteratorOperations.java Generated by the IDL-to-Java compiler (portable), version "3.0" from nameservice.idl Wednesday, January 26, 2000 3:34:52 PM PST|
|NamingContext||A naming context is an object that contains a set of name bindings in which each name is unique.|
|NamingContextOperations||org/omg/CosNaming/NamingContextOperations.java Generated by the IDL-to-Java compiler (portable), version "3.0" from nameservice.idl Wednesday, January 26, 2000 3:34:53 PM PST|
Provides the naming service for Java IDL.
The package and all its classes and interfaces
were generated by running the tool
idltojava on the file
nameservice.idl, which is a module written in OMG IDL.
The interfaces are:
These two interfaces provide the means to bind/unbind names and object
references, to retrieve bound object references, and
to iterate through a list of bindings. The
interface supplies the main functionality for the naming service, and
BindingIterator provides a means of iterating through a list
of name/object reference bindings.
BindingIteratorare included here.
public final class NameComponent-- a building block for names. (Names are bound to object references in a naming context.)
A name is an array of one or more
A name with a single
NameComponent is called
a simple name; a name with multiple
objects is called a compound name.
NameComponent object consists of two fields:
Stringused as an identifier
Stringthat can be used for any descriptive purpose. Its importance is that it can be used to describe an object without affecting syntax. The C programming language, for example, uses the the syntactic convention of appending the extension ".c" to a file name to indicate that it is a source code file. In a
kindfield can be used to describe the type of object rather than a file extension or some other syntactic convention. Examples of the value of the
kindfield include the strings
"". It is not unusual for the
kindfield to be the empty string.
In a name, each
NameComponent object except the last denotes
NamingContext object; the last
object denotes the bound object reference.
This is similar to a path name, in which the last name is the
file name, and all names before it are directory names.
public final class Binding-- an object that associates a name with an object reference or a naming context. A
Bindingobject has two fields:
binding_name- an array of one or more
NameComponentobjects that represents the bound name
BindingTypeobject indicating whether the binding is between a name and an object reference or between a name and a naming context
NamingContext has methods for
binding/unbinding names with object references or naming contexts,
for listing bindings,
and for resolving bindings (given a name, the method
resolve returns the object reference bound to it).
public final class BindingType-- an object that specifies whether the given
Bindingobject is a binding between a name and an object reference (that is, not a naming context) or between a name and a naming context.
BindingType consists of two methods and
four constants. Two of these constants are
BindingType objects, and two are
can be passed to the constructor for the class
Binding or used as parameters or return values. These
BindingType objects are:
public static final BindingType nobject-- to indicate that the binding is with an object reference
public static final BindingType ncontext-- to indicate that the binding is with a naming context
int constants can be supplied to the method
from_int to create
or they can be return values for the method
These constants are:
public static final int _nobject
public static final int _ncontext
from_intis supplied with anything other than
_ncontext, it will throw the exception
Usage is as follows:
BindingType btObject = from_int(_nobject); BindingType btContext = from_int(_ncontext);The variable
btObjectrefers to a
BindingTypeobject initialized to represent a binding with an object reference. The variable
btContextrefers to a
BindingTypeobject initialized to represent a binding with a
value returns either
in the following line of code, the variable
int bt = BindingType.value();
valuefield. This allows it to perform the function of an OUT or INOUT parameter.
The following holder classes are generated for the package
Note that in the
there is a holder class for each of the basic Java types:
StringHolder, and so on.
Note also that there is a
NameHolder class even though
there is no
Name class; similarly, there is a
BindingListHolder class even though there is no
BindingList class. This is true because in the OMG IDL
typedefs. There is no mapping from an IDL
typedef to a Java construct, but holder classes
are generated if the
typedef is for a sequence or
an array. As mapped to the
Java programming language,
Name is an array of
NameComponent objects, and a
is an array of
All holder classes have at least two constructors and one field:
valuefield -- an instance of the type being used as an OUT or INOUT parameter. For example, the
valuefield of a
NamingContextHolderwill be a
BindingHolderobject created with the default constructor will have its
valuefield set to
nullbecause that is the default value for an object. Other defaults are
0for numeric and char types, and
nullfor object references.
valuefield is initialized with the instance supplied
A holder class for a user-defined type (a Java class) has three more methods, but application developers do not use them directly.
There is only one method in a helper class that an
application programmer uses: the
narrow. Only Java interfaces mapped from IDL
interfaces will have a helper class that includes a
method, so in the
CosNaming package, only the classes
public static NamingContext narrow(org.omg.CORBA.Object obj)-- converts the given CORBA object to a
public static BindingIterator narrow(org.omg.CORBA.Object obj)-- converts the given CORBA object to a
org.omg.CosNamingand also for the class
NotFoundReason, which supplies a reason for the exception
There are Helper and Holder classes for the following exceptions:
CosNamingpackage complies with the OMG
COSNamingspecification. In other words, the APIs in Sun's naming service are implemented according to the guidelines for a naming service provided by OMG. Therefore, if a third-party vendor has implemented a naming service that is OMG compliant, it is possible to switch between Sun's implementation of
CosNamingand the third-party vendor's implementation. However, it is important to understand that there can be minor variations in the way different vendors implement the naming service, such as differences in the exception strings.
COSNamingimplementation with Sun's RMI-IIOP ORB. Here are the steps to follow:
/tmp/servicesand put the following in it:
NameService with the Root Naming
Context of the
CosNaming implementation that you
want to use.
java -classpath $(CLASSPATH) com.sun.corba.ee.internal.CosNaming.BootstrapServer -InitialServicesFile "/tmp/services" [-ORBInitialPort port]
Note that the square brackets at the end of the command indicate that specifying a port number is optional.
Now when an application calls the method
processes will contact the Bootstrap Server to get the Root Naming
CosNamingAPI, please see:
For an overview of Java IDL, please see:
JavaTM 2 Platform
Std. Ed. v1.3
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