Basic Example

The following is a Bank example that demonstrates a simple CORBA application. Included is the README, the IDL, the server code, and the client code. Refer to the demo/corba/basic directory for the Makefile.

README

bank demonstrates:

This is an Oracle8i-compatible version of the VisiBroker Bank
example. The major differences from the Vb example are:

(1) There is no server main loop. For Oracle8i the
"wait-for-activation" loop is part of the IIOP presentation (MTS
server).

(2) _boa.connect(object) is used instead of the less portable
 _boa_obj_is_ready(object) in the server object implementation to
register the new Account objects.

(3) The client program contains the code necessary to lookup the
AccountManager object (published under /test/myBank) and activate it,
and to authenticate the client to the server. (Note that object
activation and authentication, via NON_SSL_LOGIN, happen "under the
covers" so to speak on the lookup() method invocation.)

(4) There is also a tie implementation of this example, with the
server being AccountManagerImplTie.java.

Bank.IDL

// Bank.idl

module Bank {
  interface Account {
    float balance();
  };
  interface AccountManager {
    Account open(in string name);
  };
};

Server

The server code is implemented in the following:

AccountManagerImpl.java

package bankServer;

import java.util.*;

public class AccountManagerImpl
  extends Bank._AccountManagerImplBase {

  public synchronized Bank.Account open(String name) {

    // Lookup the account in the account dictionary.
    Bank.Account account = (Bank.Account) _accounts.get(name);

    // If there was no account in the dictionary, create one.
    if(account == null) {

      // Make up the account's balance, between 0 and 1000 dollars.
      float balance = Math.abs(_random.nextInt()) % 100000 / 100f;

      // Create the account implementation, given the balance.
      account = new AccountImpl(balance);

      _orb().connect(account);

      // Print out the new account.
      // This just goes to the system trace file for Oracle 8i.
      System.out.println("Created " + name + "'s account: " + account);

      // Save the account in the account dictionary.
      _accounts.put(name, account);
    }
    // Return the account.
    return account;
  }

  private Dictionary _accounts = new Hashtable();
  private Random _random = new Random();

}

AccountImpl.java

package bankServer;

public class AccountImpl extends Bank._AccountImplBase {
  public AccountImpl(float balance) {
    _balance = balance;
  }
  public float balance() {
    return _balance;
  }
  private float _balance;
}

AccountManagerImplTie.java

package bankServer;

import java.util.*;
import oracle.aurora.AuroraServices.ActivatableObject;

public class AccountManagerImplTie
  implements Bank.AccountManagerOperations, 
  ActivatableObject {

  public synchronized Bank.Account open(String name) {

    // Lookup the account in the account dictionary.
    Bank.Account account = (Bank.Account) _accounts.get(name);

    // If there was no account in the dictionary, create one.
    if(account == null) {

      // Make up the account's balance, between 0 and 1000 dollars.
      float balance = Math.abs(_random.nextInt()) % 100000 / 100f;

      // Create the account implementation, given the balance.
      account = new AccountImpl(balance);

      org.omg.CORBA.ORB.init().BOA_init().obj_is_ready(account);

      // Print out the new account.
      // This just goes to the system trace file for Oracle 8i.
      System.out.println("Created " + name + "'s account: " + account);

      // Save the account in the account dictionary.
      _accounts.put(name, account);
    }
    // Return the account.
    return account;
  }

  public org.omg.CORBA.Object _initializeAuroraObject () {
    return new Bank._tie_AccountManager(this);
  }

  private Dictionary _accounts = new Hashtable();
  private Random _random = new Random();

}

Client.java

// Client.java opens the account through the AccountManager class and manages 
// the account through the Account class */

import bankServer.*;
import Bank.*;

import oracle.aurora.jndi.sess_iiop.ServiceCtx;

import javax.naming.Context;
import javax.naming.InitialContext;
import java.util.Hashtable;

public class Client
{
  public static void main (String[] args) throws Exception {
    if (args.length != 5) {
      System.out.println("usage: Client serviceURL objectName user password "
			 + "accountName");
      System.exit(1);
    }
    String serviceURL = args [0];
    String objectName = args [1];
    String user = args [2];
    String password = args [3];
    String name = args [4];

    Hashtable env = new Hashtable();
    env.put(Context.URL_PKG_PREFIXES, "oracle.aurora.jndi");
    env.put(Context.SECURITY_PRINCIPAL, user);
    env.put(Context.SECURITY_CREDENTIALS, password);
    env.put(Context.SECURITY_AUTHENTICATION, ServiceCtx.NON_SSL_LOGIN);

    Context ic = new InitialContext(env);

    AccountManager manager =
      (AccountManager)ic.lookup (serviceURL + objectName);

    // Request the account manager to open a named account.
    Bank.Account account = manager.open(name);

    // Get the balance of the account.
    float balance = account.balance();

    // Print out the balance.
    System.out.println
      ("The balance in " + name + "'s account is $" + balance);
  }
}

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