Download Building a CORBA Server - technicalsymposium.com

Building a CORBA Server
Basic Steps for Building a CORBA
Server
1. Define the server's interfaces using IDL.
2. Choose an implementation approach for the server's
interfaces.
3. Use the IDL compiler to generate client stubs and
server skeletons for the server interfaces.
4. Implement the server interfaces.
5. Compile the server application.
6. Run the server application.
1. Defining the Server Interfaces





// StockMarket.idl
module StockMarket
{
typedef string StockSymbol;
typedef sequence<StockSymbol> StockSymbolList;







};
interface StockServer
{
float getStockValue(in StockSymbol symbol);
StockSymbolList getStockSymbols();
};
2. Choosing an Implementation
Approach

Implementation by inheritance


consists of a base class that defines the interfaces of a
particular object and a separate class, inheriting from
this base class, which provides the actual
implementations of these interfaces
Implementation by delegation

consists of a class that defines the interfaces for an
object and then delegates their implementations to
another class or classes.
3. Using the IDL Compiler


Sun's Java IDL product is this:
idltojava -fno-cpp -fclient -fserver StockMarket.idl
IDL Compiler generate number of files




Helper classes
Client Stub classes
Server Stub classes
The names of the files generated by the IDL compiler are
dependent on the language mapping used and sometimes on
command-line arguments passed to the IDL compiler.
Using the IDL Compiler (Cont)

For each IDL interface compiler generate



a source file and header file for the client stub
a source file and header file for the server
skeleton
IDL Compiler can create separate
directories for IDL module.
4. Implementing the Server
Interfaces

To keep the example as simple Java is
used as implementation language.
i) Using Server Skeletons


The server skeleton, as you have learned,
provides a framework upon which to build
the server implementation.
In Java, a server skeleton combines a set
of helper classes with an interface, for
providing the implementation.

After Compilation within StockMarket
directory are a number of files containing
client stub and server skeleton definitions:
StockSymbolHelper.java
StockSymbolListHolder.java
StockSymbolListHelper.java
StockServer.java
StockServerHolder.java StockServerHelper.java
_StockServerStub.java
_StockServerImplBase.java
StockServer.java






package StockMarket;
public interface StockServer extends
org.omg.CORBA.Object
{
float getStockValue(String symbol);
String[] getStockSymbols();
}